# Behavior of the dull (?) blade (bevel up vs. bevel down?)



## adrian (24 May 2010)

At risk of duplicating the question in another recent thread, I ask the question. How sharp does an edge need to be and how can you tell when it's not sharp enough? And do different woods behave differently in terms of how sharp the edge needs to be? 

I surfaced about 40 square feet of rough sawn American cherry with my hand planes. I'm not sure how often I sharpened tools, but I went several hours (ten? fifteen?) between sharpenings without noticing a problem. (Maybe I'm oblivious.) 

Lately I have been working in canarywood. It is surfaced already, but badly, and is not flat. I was working with two planes, a bevel down plane (45 degree cut angle) and a bevel up plane. The bevel down is sharpened at 30 degrees with a 32 deg microbevel and set for a thicker shaving (maybe .004 inch). The bevel up plane is sharpened at 45 deg (microbevel at 47), effective pitch 59 and set a thin shaving (about .001 inch). Both planes are Veritas witih A2 irons. Both blades are cambered. 

At a certain point the bevel up plane just stopped taking a shaving. It wouldn't cut. I usually blame this sort of event on the shape of the wood. But at a certain point I decided I needed another explanation, so I inspected the blade. It had an accumulation of fine dust from the wood on the edge. When I stroked the edge with a fingernail it felt smooth. It would bit into the face of my fingernail reasonably well at an acute angle, though not quite as well as when the plane was freshly sharp. But I wouldn't have considered it dull. I sharpened the edge and went back to work and the plane would cut again. For 20 minutes or so. Then it again stopped cutting completely. 

Meanwhile, I can't even remember the last time I sharpened the bevel down plane. After I finish surface jointing a board I figure it must need some attention. I remove its blade and inspect the edge. It's clearly in far worse condition than the other blade. The fingernail stroked along the edge reveals a lot of roughness. I can see some micronicks with the naked eye. It flunks the test for biting into the fingernail. This is clearly a dull blade. But this blade was still cutting when I took it out of the plane. This plane is sharpened at 30 degrees with a microbevel of about 32. 

When working with the cherry I sometimes suspected that my finish surface was suffering due to the blades getting dull, but I don't recall noticing this phenomenon even though I went far, far, longer without sharpening. 

Presumably my sharpening procedure isn't to blame, since it's the same for both blades. So what explains this difference in behavior?


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## Racers (24 May 2010)

Hi,

You need sharper tool to cut soft wood, think soft tomato and a blunt knife.

Pete


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## adrian (24 May 2010)

Canary wood is *harder* than American cherry. The latter is fairly soft, as hard woods go. Janka hardness for canarywood is 2200. For the cherry is 950.


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## Racers (24 May 2010)

Hi,

Sorry I thought is was soft stuff  

Pete


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## Paul Chapman (24 May 2010)

adrian":3lasm5kw said:


> I'm not sure how often I sharpened tools, but I went several hours (ten? fifteen?) between sharpenings without noticing a problem.



Sounds to me like you are not sharpening your planes often enough. Furthermore, if you can plane for ten or fifteen hours without noticing a problem, then possibly you don't know what a really sharp plane feels like.

It's difficult to say how often you need to sharpen because woods vary so much - but I think you need to sharpen a lot more frequently.

Cheers :wink: 

Paul


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## woodbloke (24 May 2010)

Paul Chapman":pcvm48r9 said:


> adrian":pcvm48r9 said:
> 
> 
> > I'm not sure how often I sharpened tools, but I went several hours (ten? fifteen?) between sharpenings without noticing a problem.
> ...


Beat me to it  I sharpen the iron, bevel up, bevel down whatever every twenty minutes or so, sometimes sooner. If your planing teak, it needs to be done every 5 minutes and that's pushing it! - Rob


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## adrian (24 May 2010)

Paul Chapman":37xns5ir said:


> adrian":37xns5ir said:
> 
> 
> > I'm not sure how often I sharpened tools, but I went several hours (ten? fifteen?) between sharpenings without noticing a problem.
> ...



Well, I'd like to think that the blades are sharp right after I sharpen them, in which case I have a period of time where I feel a reall sharp blade. If they aren't sharp at that point...then sharpening more often isn't going to help a lot. 

The only thing I can offer as evidence of sharpness is that I can get a smooth surface, free from tear out, on curly maple and with grain reversals in the cherry and canary wood. 



> It's difficult to say how often you need to sharpen because woods vary so much - but I think you need to sharpen a lot more frequently.
> 
> Paul



I agree that more frequent sharpening wouldn't be a bad thing. In the past I could expect to spend 45 minutes sharpening one plane. This doesn't encourage frequent sharpening. If everything is going well I have been able to do it in something like 5-10 minutes lately, but things don't always go well. In the latest case I've started experimenting with only going back to the polishing stone, and that seems to work OK and is quite fast. But is that good enough? 

And so far the replies have focused on this problem with my work practice. But I'd like to understand why I'm observing such different behavior with the two different planes. Why will my bevel down plane still cut when it's really quite dull and the bevel up plane stops cutting entirely when the edge is much sharper?


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## Paul Chapman (24 May 2010)

adrian":37lg93as said:


> In the past I could expect to spend 45 minutes sharpening one plane. This doesn't encourage frequent sharpening. If everything is going well I have been able to do it in something like 5-10 minutes lately, but things don't always go well.



When a plane gets blunt, the end of the blade becomes rounded over. If you go on planing as long as you do, it will get more and more blunt and more rounded. Re-honing a blade shouldn't be taking 45 minutes but by leaving it so long between honings you are probably having to remove a lot of metal. Re-honing a blade should only take a couple of minutes at most, but that requires you to re-hone as soon as the sharpness starts to wear off.

If I were you I'd review your honing regime - I think that's where the problem is.

Hope this helps.

Cheers :wink: 

Paul


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## Steve Maskery (24 May 2010)

adrian":3tnpxrdp said:


> Canary wood is *harder* than American cherry. The latter is fairly soft, as hard woods go. Janka hardness for canarywood is 2200. For the cherry is 950.



Well that doesn't accord with my experience. Canary whitewood (AKA Poplar, tulipwood) is much softer than cherry. Yes, cherry is not the hardest of hardwoods, but it's noticeably harder than Canary. Just hit a piece of each with a hammer and see which has the biggest ding. You can easily dent Canary with your fingernail.

I wonder if there is more than one type of canary whitewood?

S


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## adrian (24 May 2010)

Steve Maskery":2unvu08l said:


> adrian":2unvu08l said:
> 
> 
> > Canary wood is *harder* than American cherry. The latter is fairly soft, as hard woods go. Janka hardness for canarywood is 2200. For the cherry is 950.
> ...



Canary whitewood sounds like something else. The canary wood I'm talking about is an exotic from Central and South America in the genus Centrolobium. http://curiouswoods.com/wood--Canary-Wood--CW. It's clearly a lot heavier than the cherry, and I doubt I could dent it easily by fingernail (though I don't have it handy at the moment to check).


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## adrian (24 May 2010)

Paul Chapman":zxdn8cvc said:


> If I were you I'd review your honing regime - I think that's where the problem is.



Since I honed the two blades using exactly the same method, my honing regime (or lack thereof) cannot explain the difference between the blades. One blade cuts for 15 minutes and then stops completely while still sharp enough that the edge is smooth and it bites into my fingernail. The other one cuts for hours even after the edge is ragged and the edge skitters across the fingernail surface without biting. The dull blade still cuts and the sharper one does not.

Why?


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## Mike H (24 May 2010)

Cherry is really fairly soft as temperate hardwoods go, but it is not totally the strength of the wood wich dictates how long the blade will last.

For example a long stored air dried piece of english oak will often plane better that a brittle over kiln dried softer import. I had a batch of American Ash 2 years ago wich resisted most attempts with the plane, I reckon they had it in the oven too long and too hot.

Also some woods plane fine one one face, but the figured face, even ignoring tearout, is really hard on the blade. Try for example Silky Oak on the lovely but deadly show face.

If you are not sure when to sharpen, then try this experiment with two blades equally well sharpened. Plane away for a tad too long with the first one, then change to the fresh blade. At the first stroke you will probably fall off the end of the bench and realise why you were dripping with sweat before! Suddenly the planing turns back from chore to shear pleasure. That is my yardstick.

With a heavy plane, say a 5 and a half, resting it on the wood and just pushing should produce a good shaving, if not the blade is getting blunt or the shaving is too thick for one pass.

I purchase quite a few blades for my main planes and gang sharpen. With one blade I would be likely to go less than 30 minutes. Less with end grain or to get a high angle bevel up to sing.


Mike 

8)


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## adrian (24 May 2010)

Mike H":3ltojnxm said:


> With a heavy plane, say a 5 and a half, resting it on the wood and just pushing should produce a good shaving, if not the blade is getting blunt or the shaving is too thick for one pass.



So you mean without any downward pressure (except the weight of the plane)? 



> With one blade I would be likely to go less than 30 minutes. Less with end grain or to get a high angle bevel up to sing.



A high angle bevel up would get dull faster?


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## lwilliams (24 May 2010)

adrian":3f7jl8mu said:


> ...The bevel up plane is sharpened at 45 deg (microbevel at 47), effective pitch 59 and set a thin shaving (about .001 inch). Both planes are Veritas witih A2 irons.
> 
> At a certain point the bevel up plane just stopped taking a shaving. It wouldn't cut. ... I sharpened the edge and went back to work and the plane would cut again. For 20 minutes or so. Then it again stopped cutting completely.
> 
> ...



What you're experiencing is the accelerated wear caused by too small a clearance angle. The 12º clearance angle is marginal at best and then for a relatively acute bevel angle and very light cuts in a relatively soft wood or for end grain work. Increasing the bevel angle to 47º only increases the difficulty in cutting the wood. This increases deflection of wood fibers ahead of the cutting edge and the resulting spring back of the fibers which rub on the back of the iron and increase dulling wear. 

You can verify this by using a more acute 30º bevel angle and you'll see the edge life is greater. If you had an O-1 iron you could go to a 25º bevel and increase edge life even more.

The best approach though is to go to a plane that offers 15º or more of clearance behind the iron. The steeper the pitch, the more resistance to cutting and more deflection so you need even more clearance with steeper pitch planes.


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## adrian (24 May 2010)

lwilliams":yzgpbcp3 said:


> What you're experiencing is the accelerated wear caused by too small a clearance angle. The 12º clearance angle is marginal at best and then for a relatively acute bevel angle and very light cuts in a relatively soft wood or for end grain work. Increasing the bevel angle to 47º only increases the difficulty in cutting the wood. This increases deflection of wood fibers ahead of the cutting edge and the resulting spring back of the fibers which rub on the back of the iron and increase dulling wear.
> 
> You can verify this by using a more acute 30º bevel angle and you'll see the edge life is greater. If you had an O-1 iron you could go to a 25º bevel and increase edge life even more.



Of course I raised the bevel angle quite intentionally, as the wood has some grain reversals that tend to give tear out with a 45 degree cutting angle. So I don't want to go to a more acute bevel angle. I'd rather not deal with adding a back bevel to increase the clearance angle if it can be avoided. 

Another observation is that the blade doesn't seem to have worn at a faster rate, but to have stopped cutting at a faster rate. Is it possible that the dust that sticks to the bevel is decreasing the clearance and interfering with the cut? (I have noticed that with the canary wood the blade tends to accumulate a layer of dust around the edge that cannot be removed with just a dry cloth.) 



> The best approach though is to go to a plane that offers 15º or more of clearance behind the iron. The steeper the pitch, the more resistance to cutting and more deflection so you need even more clearance with steeper pitch planes.



Veritas sell a high angle blade for their plane with a 12 degree bed angle. Is this not a combination that can be expected to work well? I don't think I've seen a bevel up plane with a 15 degree bed angle.


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## Steve Maskery (24 May 2010)

adrian":2ldrjl46 said:


> Canary whitewood sounds like something else. The canary wood I'm talking about is an exotic from Central and South America in the genus Centrolobium. http://curiouswoods.com/wood--Canary-Wood--CW. It's clearly a lot heavier than the cherry, and I doubt I could dent it easily by fingernail (though I don't have it handy at the moment to check).



Hmm OK, well at least we agree we are not talking about the same thing.

But do yo know what I think has happened? I think that the person resposible for that web entry is confused. Or at least, there is general confusion.

OK. AFAIK< there is only one commercially available Canary wood inthe UK. Canary whitewood, tulipwood, Americam Poplar. It's all the same. I don't have a botanical reference.

BUT. There is another timber, with all the characteristics of that described, called TULIPWOOD. It's botanically very different, it just shares the same name. I think I have a piece somewhere. Now that IS harder than cherry. I've only ever come across it as turnery blanks from Craft Supplies.

So, I would suggest, either Craft SUpplies got confused between Tulipwood/ Tulipwood or Canary/canary. about 15 years ago (which I dare say is entirely possible), or these people have now.
But the picture and description in that link bears no resemblance to Canary that you would find in any commercial timberyard.

I know that this a bit of distraction from the main thrust of the thread, I just want to be sure about what we are talking about.

Anyway, back to the point.....
S


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## Wiley Horne (24 May 2010)

Hi Adrian,

My experience is that if a plane 'just stops cutting'--meaning downward pressure won't hold it in the cut--then you're out of clearance angle.

With the bevel up plane (unless it's a Holtey 98), the plane will be bedded at 12 degrees, which means you have a max. of 12 degrees of clearance. According to Leonard Lee's results in his sharpening book, you need a minimum of 5 degrees in hardwood, or else the plane will not work. If you are not sharpening frequently, it's pretty easy to lose the cushion of 7 degrees of clearance to accumulated wear on the lower blade surface, or rounding due to stropping on the back of the blade. Others have reported (sorry, I don't have the links to hand right now) that planing with a high attack angle, like 59 degrees, will accelerate the wear noticeably, compared to the same plane at, say, 50 degrees. 

Some combination of infrequent sharpening, high attack angle, stropping of the blade back, etc--may be causing you to lose your 7 degrees of available clearance rapidly. It's not sufficient, when clearance is limited, to have the blade feeling sharp. It can be fairly sharp to the touch, yet the plane won't cut, if the blade back has in the ballpark of 7 degrees of rounding or wear at the microlevel.

Here's a suggestion: Do you have a grinder? Or a belt sander? If so, get a fresh start on the bevel up blade by removing some metal. Take a square and mark the blade back about 1mm up from the current edge, and grind back to that line. That should get rid of any rounding or excessive wear on the blade back near the edge. Then, going forward, sharpen more frequently so that you are removing the wear and not allowing it to accumulate over sharpenings. And to control what your sharpening may be doing do to the blade back, use David Charlesworth's ruler trick (and no other stropping or microbevels) to limit the clearance loss to 1 degree.

Wiley


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## David C (24 May 2010)

I think Wiley has given an excellent answer.

If the timber is remotely hard or abrasive, I would be sharpening every 15 minutes or so.

best wishes

David Charlesworth


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## Steve Elliott (24 May 2010)

adrian":1vnpf9g2 said:


> I'd like to understand why I'm observing such different behavior with the two different planes. Why will my bevel down plane still cut when it's really quite dull and the bevel up plane stops cutting entirely when the edge is much sharper?



The difference in clearance angles between the two planes is only one degree and that's not the entire cause of the difference in performance. I've found when I'm using a very dull blade that taking a thicker shaving will keep it working longer. With a thick shaving there's downward pressure from the wood hitting the front of the blade that helps counteract the upward pressure due to loss of clearance. The plane will be hard to push for three reasons: increased force to push the rounded edge into the wood, more force needed to take a thick shaving, and increased downward pressure needed to keep the blade in the cut. But it's still possible to take a thick shaving. If the same blade is retracted to take a very thin shaving it becomes harder to keep the blade in the cut at all. This is where the plane just stops cutting.

Since your bevel-up plane blade has a 47 degree bevel angle it might be hard to take a .004" thick shaving even if the blade was sharp.

My block planes are among my favorites and of course they're bevel-up. Even with the low angle block bedded at 12 degrees I've been able to use blades that were fairly dull for fitting work, typically taking a thick but narrow shaving. A bevel-up smoother would be used for taking thinner shavings so it would need a sharper blade.


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## adrian (24 May 2010)

Steve Maskery":2c86oibq said:


> adrian":2c86oibq said:
> 
> 
> > Canary whitewood sounds like something else. The canary wood I'm talking about is an exotic from Central and South America in the genus Centrolobium. http://curiouswoods.com/wood--Canary-Wood--CW. It's clearly a lot heavier than the cherry, and I doubt I could dent it easily by fingernail (though I don't have it handy at the moment to check).
> ...



Perhaps it's significant that I'm not in the UK. 


> But the picture and description in that link bears no resemblance to Canary that you would find in any commercial timberyard.



The picture is a bit bland, but looks reasonable. The description seems reasonable. My first experience with this timber was from a mail order supplier who claimed it weighed 31 lbs/ft^3. But the board felt heavy so I weighed it and the actual density was 45 lb/ft^3. This supplier seemed to have mixed up this wood with tulip wood. 

I tried pressing my thumbnail into it. If I press as hard as possible it leaves a very faint mark. On American cherry the thumbnail leaves a clear indentation. The cherry is definitely softer. 

More pictures of the wood I have can be seen here: http://www.hobbithouseinc.com/personal/woodpics/canary.htm


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## adrian (25 May 2010)

Wiley Horne":osyghn4c said:


> Hi Adrian,
> 
> My experience is that if a plane 'just stops cutting'--meaning downward pressure won't hold it in the cut--then you're out of clearance angle.



This is very helpful to know. It explains why the bevel up and bevel down planes behave differently. 



> With the bevel up plane (unless it's a Holtey 98 ), the plane will be bedded at 12 degrees



Little beyond my budget, I fear. 



> Here's a suggestion: Do you have a grinder? Or a belt sander? If so, get a fresh start on the bevel up blade by removing some metal. Take a square and mark the blade back about 1mm up from the current edge, and grind back to that line. That should get rid of any rounding or excessive wear on the blade back near the edge. Then, going forward, sharpen more frequently so that you are removing the wear and not allowing it to accumulate over sharpenings. And to control what your sharpening may be doing do to the blade back, use David Charlesworth's ruler trick (and no other stropping or microbevels) to limit the clearance loss to 1 degree.


I don't understand how this procedure would change anything. If I hone until a burr is raised and then work the back (with the ruler trick) until a burr is raised then haven't I removed any worn area? 

(Note that I've never stropped and I currently use the ruler trick on the back. I've been attempting the sharpening method described by Charlesworth where I sharpen at 45 degrees on the 1000 grit stone and then at 47 degrees on the 8000 grit stone.)


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## lwilliams (25 May 2010)

adrian":1chitc2z said:


> Of course I raised the bevel angle quite intentionally, as the wood has some grain reversals that tend to give tear out with a 45 degree cutting angle. So I don't want to go to a more acute bevel angle. I'd rather not deal with adding a back bevel to increase the clearance angle if it can be avoided.
> 
> Another observation is that the blade doesn't seem to have worn at a faster rate, but to have stopped cutting at a faster rate. Is it possible that the dust that sticks to the bevel is decreasing the clearance and interfering with the cut? (I have noticed that with the canary wood the blade tends to accumulate a layer of dust around the edge that cannot be removed with just a dry cloth.)



A back bevel of any type will reduce your clearance angle. I have no doubt you were using the steeper cutting geometry intentionally. I was only offering a way you could verify the issue is indeed the clearance angle. I think you're missing the wear bevel that appears on the back of the iron quickly in a configuration like you're using.


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## lwilliams (25 May 2010)

Wiley Horne":pdppfk47 said:


> According to Leonard Lee's results in his sharpening book, you need a minimum of 5 degrees in hardwood, or else the plane will not work. If you are not sharpening frequently, it's pretty easy to lose the cushion of 7 degrees of clearance to accumulated wear on the lower blade surface, or rounding due to stropping on the back of the blade. Others have reported (sorry, I don't have the links to hand right now) that planing with a high attack angle, like 59 degrees, will accelerate the wear noticeably, compared to the same plane at, say, 50 degrees.



Results? What results? I've read and reread Lee's stuff ( http://tinyurl.com/3abjmbs ) and I don't see any experiments. No research, just a few statements and I can't find where he says what everyone has been reporting.

I believe you have a couple middle pitch bevel-down planes. Hone one at 37º and give it a try. You'll find you're experiencing exactly what Adrian is reporting. You're plane will quickly start balking not working like you're used to it working. Set up this way, you'll be working with an 18º clearance angle and a 55º cutting angle. If an 18º clearance angle with a 55º cutting angle isn't adequate for a bevel down plane, why would an 11º clearance angle with a 59º cutting angle be perfectly fine in a bevel-up plane? What is different?


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## Steve Elliott (25 May 2010)

lwilliams":2m7r6hy2 said:


> Results? What results? . . .
> I believe you have a couple middle pitch bevel-down planes. Hone one at 37º and give it a try. You'll find you're experiencing exactly what Adrian is reporting. You're plane will quickly start balking not working like you're used to it working. Set up this way, you'll be working with an 18º clearance angle and a 55º cutting angle. If an 18º clearance angle with a 55º cutting angle isn't adequate for a bevel down plane, why would an 11º clearance angle with a 59º cutting angle be perfectly fine in a bevel-up plane? What is different?



I've done a large number of carefully controlled experiments using planes bedded at 45 degrees with blades honed to a final bevel angle of 34 degrees. This leaves exactly 11 degrees of clearance when the blade is fresh. In none of my tests did the plane balk. While I usually stopped the tests after about 600 lineal feet of planing it wasn't because the plane was balking, but rather because I'd passed the point where I would expect a competent woodworker would resharpen. I did a few tests that went to 1,000 lineal feet or more and was still able to keep the blade in the cut.

Given that my results with 11 degrees of clearance were so good, I do not believe that a bevel-up plane with 12 degrees of clearance will show inherent clearance problems. My own experience with low angle block planes bears this out.


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## lwilliams (25 May 2010)

Steve Elliott":3s7gbjbl said:


> ...Given that my results with 11 degrees of clearance were so good, I do not believe that a bevel-up plane with 12 degrees of clearance will show inherent clearance problems. My own experience with low angle block planes bears this out.



And the accelerated dulling and wear bevel to the back of the iron so many like Adrian report in these 12º bevel-up planes is the result of? The problems I experience with my own middle pitch planes on those occasions where I got lazy and increased honing angle rather than spend a minute or two regrinding resulted from? In one way or another, I deal with clearance angles almost every day in my work. They're all too real and critical.

on edit: I'm having trouble equating your 600 lineal feet to real world at the bench. I have no idea of how many feet of a single pass I expect to take with a plane. I think more in terms of hours of use and I expect to get at least an hour or two of steady use from a sharpening. I also don't know what you expect in terms of surface quality or how much extra work you're willing to exert. 

I can give a good example from history where the structurally flawed wooden miter plane eventually replaced the strike block which cost only 1/3 as much and I can show that inadequate clearance angles were the most likely contributing factor.

It's also really easy to demonstrate burnished surfaces that result from inadequate clearance angles. Burnished surfaces inhibit adhesive, finish and especially stain penetration. Burnished surfaces are a problem in most Western style woodworking applications.


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## Steve Elliott (25 May 2010)

lwilliams":yp46bjoj said:


> And the accelerated dulling and wear bevel to the back of the iron so many like Adrian report in these 12º bevel-up planes is the result of? The problems I experience with my own middle pitch planes on those occasions where I got lazy and increased honing angle rather than spend a minute or two regrinding resulted from? In one way or another, I deal with clearance angles almost every day in my work. They're all too real and critical.



I've been reading reviews of bevel-up planes since their emergence as smoothers and I've followed a number of hand tool messageboards for ten years without hearing much about "accelerated dulling and wear bevel to the back of the iron so many like Adrian report in these 12º bevel-up planes." During the same time I've been using a microscope to examine the wear that forms on the lower surface of the cutting edge. I don't consider myself an expert on many phases of traditional woodworking, having used power tools for the most part in my professional career, but in the area of blade geometry and wear I think I've done enough careful work that I know what I'm saying and can back it up.

After reading your dismissive comments about jigs I've started to wonder how closely you know what the bevel angle is at the tip of your freehand-honed blades. Your recent description of a strike block plane bedded at 40 degrees that left a burnished surface on the wood with a freshly honed blade "at 30 degrees" made me wonder whether that angle was just a guess. Do you have a way of measuring the angle at the very tip of a blade? Even a little bit of rocking will leave the tip at a higher angle than the overall bevel. I'm not trying to criticize, but rather to understand how the performance you describe could be so different from my own experience.

One correction I'd like to make to my previous post is that the 34 degree bevel was the result of a 31-1/2 degree main bevel and a 2-1/2 degree back bevel. This means that the clearance angle was 13-1/2 degrees rather than the 11 degrees I described. I stand by my good experience with block planes bedded at 12 degrees. These clearance angles are still much less than the 18 degrees you suggest will cause a plane to balk.


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## lwilliams (25 May 2010)

Steve Elliott":37bg343e said:


> ...I've started to wonder how closely you know what the bevel angle is at the tip of your freehand-honed blades. Your recent description of a strike block plane bedded at 40 degrees that left a burnished surface on the wood with a freshly honed blade "at 30 degrees" made me wonder whether that angle was just a guess. Do you have a way of measuring the angle at the very tip of a blade? Even a little bit of rocking will leave the tip at a higher angle than the overall bevel. I'm not trying to criticize, but rather to understand how the performance you describe could be so different from my own experience.
> 
> One correction I'd like to make to my previous post is that the 34 degree bevel was the result of a 31-1/2 degree main bevel and a 2-1/2 degree back bevel. This means that the clearance angle was 13-1/2 degrees rather than the 11 degrees I described. I stand by my good experience with block planes bedded at 12 degrees. These clearance angles are still much less than the 18 degrees you suggest will cause a plane to balk.



Actually, I try to keep the honed bevel at the edge small enough that it would be incredibly difficult to measure it. Am I working to within a 1/2º? I seriously doubt it, I freehand hone. Frankly, if I had to use a honing guide I'd be in trouble because there isn't a honing guide made that can handle a large percentage of the profiled irons I sharpen. Let me point out that you don't know yours either. Unless you're also abrading away your honing guide, your angle changes with each pass on the stone. In the case of the acute 2 1/2º back bevel, that change becomes very significant in a hurry.


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## Steve Elliott (25 May 2010)

lwilliams":3ld4ugkw said:


> Actually, I try to keep the honed bevel at the edge small enough that it would be incredibly difficult to measure it. Am I working to within a 1/2º? I seriously doubt it, I freehand hone. Frankly, if I had to use a honing guide I'd be in trouble because there isn't a honing guide made that can handle a large percentage of the profiled irons I sharpen. Let me point out that you don't know yours either. Unless you're also abrading away your honing guide, your angle changes with each pass on the stone. In the case of the acute 2 1/2º back bevel, that change becomes very significant in a hurry.



My secondary bevels are also very narrow but I've made a device using a laser pointer that allows me to measure the bevels to well less than a half a degree. Here's a picture of a freshly sharpened Hock high carbon blade in the device:







This shows the back bevel (on the left) at about 2.6 degrees and the main bevel at about 29.1 deg.

I've been using this laser thing to calibrate my honing jig, not that it's important to be within .1 degree of anything. I can put a freehand-honed blade in it and get a very accurate result for the angle at the tip.

To keep things in perspective, let me say that I have great respect for your ability to make profiled blades that perform well in your planes. Your specialty is in the mainstream of traditional woodworking and my experiments are more like a high school science project on steroids. But as a hobby it's been a lot of fun and I think my results may be of use to others.


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## Wiley Horne (25 May 2010)

adrian":1qeb9ipm said:


> Wiley Horne":1qeb9ipm said:
> 
> 
> > Hi Adrian,
> ...


I don't understand how this procedure would change anything. If I hone until a burr is raised and then work the back (with the ruler trick) until a burr is raised then haven't I removed any worn area? 

Adrian,

I should have mentioned this before, but we are comparing a plane attacking at 45 degrees with one attacking at 59 degrees--the 59 degree plane is approaching a scraping angle, and will have a shorter blade life. Especially against a wood with 2200 Janka hardness, which is way harder than sugar maple. A better comparison would be to grind the BU blade to 33 degrees or so (as Larry Willliams suggested), so that both planes are attacking at 45 degrees.

However, let's set the comparison of planes aside and focus on the bevel up plane. Here's what may be happening….This analysis is based on your observation that the plane stops cutting prematurely; it stops cutting even though it is sharp enough that it should continue with enough applied force.

A couple preliminaries. The high angle, bevel up set up, in A2, creates a demanding sharpening situation. Compare sharpening the 30 degree primary angle BD blade with the 47 degree BU blade. The overall problem in sharpening the two blades is the same--to remove the lower wear bevel. But here the similarities end. When you work the bevel of a BU plane, you are trying to grind the lower wear bevel off the opposite face--the back of the blade. This is different than working the bevel of a BD plane, where you are removing the lower wear bevel from the same face you are working. Just because of blade geometry, it takes a lot more metal removal from the BU blade than the BD blade--I would say about twice as much--to achieve the same degree of lower wear bevel removal. The large included angle of 47 degrees accentuates this effect, compared to the 30 degree (primary angle) BD blade. Draw a scale picture of this, and you can see how the geometry makes a tougher problem of the high-angle BU blade. 

Plus, A2 is a wear-resistant steel. It resists metal removal, even though you need to remove more metal from the BU blade.

So we're up against 3 things--an abrasive-resistant steel, a large included angle on the blade, and the fact that we are trying to remove a wear bevel on the opposite side of the blade. This latter fact means that you could roll up a burr, and still have wear bevel left untouched. What could be happening is that, even though you are generating a burr on the bevel side of the BU blade, it is not a large enough burr to have fully rolled up the wear bevel on the blade back. Then you flip the blade over and 'back off'--remove the primary burr with the ruler trick--but still there is some wear bevel down there just under the blade edge which is hiding from you. The blade is not quite sharp, still a bit ragged and rounded at the edge. So even after sharpening, it's halfway on the path to dull, and sure enough the lower wear bevel sets up more quickly than it should, and soon the plane can't be held in the cut. [In this situation, reasonable people can debate whether the lower wear bevel has grown to the point where clearance is limiting, or whether you just have a rounded dull edge which can't get a bite.] 

Anyway, you can test this proposition by grinding back about a millimeter, to where you know you're into virgin metal and beyond any wear bevel. And sharpen that edge. See if you get a longer planing run. If you do, then the original problem was incomplete sharpening due to the factors discussed. If not, then either live with it or try a more acute blade angle. 

Final thought: I have never planed canary wood, but it looks to me like 20 minutes of planing a Janka 2200 wood at a 59 degree attack is about what is possible.

Wiley


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## Paul Chapman (25 May 2010)

Great analysis, Wiley - it's all about getting rid of the rounded over portion of the edge which develops as the blade blunts. Quite easy to see with a low-power magnifying glass whether the roundness has been removed.

Cheers :wink: 

Paul


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## bugbear (25 May 2010)

adrian":1lbx4jmq said:


> In the past I could expect to spend 45 minutes sharpening one plane. This doesn't encourage frequent sharpening. If everything is going well I have been able to do it in something like 5-10 minutes lately, but things don't always go well.



OK, this is odd. Even David Charlesworth, known for his (ahem) "methodical" approaches sharpens a plane blade quicker than that on his video, including all the exposition.

45 minutes is long enough to recondition a fairly knackered "car boot" blade!

BugBear


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## woodbloke (25 May 2010)

bugbear":3lgbpctw said:


> adrian":3lgbpctw said:
> 
> 
> > In the past I could expect to spend 45 minutes sharpening one plane. This doesn't encourage frequent sharpening. If everything is going well I have been able to do it in something like 5-10 minutes lately, but things don't always go well.
> ...


Agreed...if you're spending 45 mins to hone a blade, something is drastically wrong! - Rob


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## adrian (25 May 2010)

Wiley Horne":wnmt41yh said:


> I should have mentioned this before, but we are comparing a plane attacking at 45 degrees with one attacking at 59 degrees--the 59 degree plane is approaching a scraping angle, and will have a shorter blade life. Especially against a wood with 2200 Janka hardness, which is way harder than sugar maple. A better comparison would be to grind the BU blade to 33 degrees or so (as Larry Willliams suggested), so that both planes are attacking at 45 degrees.



I agree that if I want to focus on the bevel up vs. bevel down issue that getting the cutting angle the same makes sense. I think my other BU blade is sharpened at 35 which is closer, at least, so maybe I can try comparing that one. 



> However, let's set the comparison of planes aside and focus on the bevel up plane. Here's what may be happening….This analysis is based on your observation that the plane stops cutting prematurely; it stops cutting even though it is sharp enough that it should continue with enough applied force.
> 
> A couple preliminaries. The high angle, bevel up set up, in A2, creates a demanding sharpening situation. Compare sharpening the 30 degree primary angle BD blade with the 47 degree BU blade. The overall problem in sharpening the two blades is the same--to remove the lower wear bevel. But here the similarities end. When you work the bevel of a BU plane, you are trying to grind the lower wear bevel off the opposite face--the back of the blade. This is different than working the bevel of a BD plane, where you are removing the lower wear bevel from the same face you are working. Just because of blade geometry, it takes a lot more metal removal from the BU blade than the BD blade--I would say about twice as much--to achieve the same degree of lower wear bevel removal. The large included angle of 47 degrees accentuates this effect, compared to the 30 degree (primary angle) BD blade. Draw a scale picture of this, and you can see how the geometry makes a tougher problem of the high-angle BU blade.



Is most of the wear on the underside? It's not evenly split between the top side and bottom side of the edge? 

I drew some pictures and tried to understand the statements you made above. I agree that if the goal is to remove a wear bevel from the underside then things are much worse in the case of the bevel up plane. I do not agree that a large angle (47 deg) is worse than a smaller angle. It would be worse at 33 degrees. In fact, the larger the bevel angle the less metal needs to be removed in this case. (The same result is true for the bevel down case.) 

Details aside, it is clear that you have to remove more metal in the bevel up case. This would seem to be a major advantage to the bevel down configuration. 



> So we're up against 3 things--an abrasive-resistant steel, a large included angle on the blade, and the fact that we are trying to remove a wear bevel on the opposite side of the blade. This latter fact means that you could roll up a burr, and still have wear bevel left untouched. What could be happening is that, even though you are generating a burr on the bevel side of the BU blade, it is not a large enough burr to have fully rolled up the wear bevel on the blade back. Then you flip the blade over and 'back off'--remove the primary burr with the ruler trick--but still there is some wear bevel down there just under the blade edge which is hiding from you. The blade is not quite sharp, still a bit ragged and rounded at the edge.



What if I actually raise a burr from the back side rather than just cutting off the burr that was produced by working the bevel side? Wouldn't this guarantee that any wear bevel has been removed? 

Do you think I should be able to see these things under a 10X loupe? I imagine that if I can detect the wear bevel it will show up as a line of reflection at the edge. 



> Anyway, you can test this proposition by grinding back about a millimeter, to where you know you're into virgin metal and beyond any wear bevel. And sharpen that edge. See if you get a longer planing run. If you do, then the original problem was incomplete sharpening due to the factors discussed. If not, then either live with it or try a more acute blade angle.



I'll admit that I'm reluctant to do this because it'll probably take me a couple hours once I get my camber re-established and everything...and the benefit remains unclear. 

One other observation. Since people keep saying I'm supposed to be able to sharpen in the blink of an eye, I tried a less thorough sharpening approach the last time the blade quit cutting. Normally I've been sharpening at 45 until I get a burr (which means the 47 deg bevel is removed). Remove burr on the back. Then I do 5 strokes in each position (cambered blade) on the polishing stone, and a few strokes on the back again. (All strokes on the back are with the ruler trick.)

But getting the burr at 45 deg takes about 50 strokes (which I then have to do in 5 positions to get all along my cambered edge.) So instead I just did about 10 strokes in each position on the polishing stone and a few strokes on the back. After doing this the plane started cutting again. I didn't closely monitor how long it cut for, but it was at least 15-20 minutes. In other words, it wasn't dramatically shorter than the lifespan I got with a full resharpening. But it doesn't sound like this procedure is adequate to remove a wear bevel on the back. 



> Final thought: I have never planed canary wood, but it looks to me like 20 minutes of planing a Janka 2200 wood at a 59 degree attack is about what is possible.



Does hardness directly relate to edge longevity? This wood is typically described as being easy to work with hand tools despite being hard. (Teak is softer, but worse, from what I understand, due to abrasive extractives.)


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## adrian (25 May 2010)

woodbloke":1eygcekb said:


> bugbear":1eygcekb said:
> 
> 
> > adrian":1eygcekb said:
> ...



In the past my stones weren't flat and I would work for ever to try to get the burr to reach the edges of the blade because the bevels (and the backs) weren't flat. Fixed that, I think. 

I did say that the 45 minutes case occurs when things aren't working properly. One example is the blade slips in the honing guide and I take strokes with it crooked at too high and angle. 

Now David seems to get by with a lot fewer strokes than I need. I'm not sure exactly why that is. If it's his stones, or the size of my secondary bevel. I usually seem to require 50-100 strokes at each position along the camber.

I've been sharpening some blades (including this one) by methods based on his video. Before I spent a lot more time on the polishing stone. I'm not sure if stinting on the polishing is OK...though the blades do seem to cut. I just read recently somewhere (maybe in Hock's book?) that a greater understanding of the metallurgy leads one to polish more.


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## bugbear (25 May 2010)

adrian":7vu9gywe said:


> But getting the burr at 45 deg takes about 50 strokes (which I then have to do in 5 positions to get all along my cambered edge.)



I don't understand this at all. I simply can't visualise what you're doing.

50 strokes is a LOT. To me it means you're either removing too much metal, or using too fine an abrasive.

How cambered is your edge? (i.e. what's the "sagitta" of the curved edge).

When you say "5 positions", are you trying to approximate a curve by multiple straight lines?

Are you using a honing guide?

Are you re-locating the blade in the guide (if used) for each "position"?

BugBear


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## adrian (25 May 2010)

I started a new topic at https://www.ukworkshop.co.uk/forums/post495251.html#495251 to talk about basic sharpening in the hopes of keeping this one for talk about relief angles and blade geometry. In my new post I answer Bugbear's questions about my sharpening technique.


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## bugbear (25 May 2010)

Paul Chapman":21wue0jo said:


> Great analysis, Wiley - it's all about getting rid of the rounded over portion of the edge which develops as the blade blunts. Quite easy to see with a low-power magnifying glass whether the roundness has been removed.
> 
> Cheers :wink:
> 
> Paul



Hmm. Actually a good loupe (say 8x or 10x) might be a wise investment for Adrian. And anyone else, for that matter!

BugBear


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## Derek Cohen (Perth Oz) (25 May 2010)

Hi Adrian

I am late to the thread, and there is little I can add to the excellent information you have received from Steve, Wiley and Larry. I am not going to go there, but will instead make a couple of observations and suggestions.

First of all I do think that your expectations of 59 degrees versus 45 degree cutting angles needs to be revisited - there is no way that they will perform the same. The edges do not enter the wood (cut) in the same way, and the abrasive properties of the wood act differently upon them. 

From your description I would argue that you can significantly improve your sharpening of a BU blade. 

Question - On the BU blade, are you honing a full face or a secondary bevel?

The length of time (45 minutes or 50 strokes) it takes you to hone an edge suggests that you are honing a full face, or a wide secondary bevel, or using too fine a grit. A wide bevel is very inefficient. I take about 2 minutes from start to finish (just a couple of strokes on each stone). I only work a micro secondary bevel. I only use a 25 degree primary bevel. Anything over that will create more metal to remove, especially if you add a camber. Cambering a micro secondary bevel takes very little time.

Secondly, while the Ruler Trick is generally an excellent strategy for users of honing guides or on BD blades, I avoid it on BU blades. The reason is that I want to strop the back of the BU blade as I work. I do this freehand. The micro back bevel of the RT makes this strategy very difficult, if not impossible. Although the back bevel angle is so small that I doubt it decreases the clearance angle significantly, the back of the blade is now no longer coplanar and I will not be able to reach the back of the blade by running it on the strop. Stropping likely minimises the incusion of a wear bevel, and the edge can be maintained for at least 3 times as long. I might add that I have never experienced the efffects that you described earlier. 

What I am also trying to be clear on is that the problem is not with the wood you are using, but very likely with the way the blade is prepared. 

Regards from Perth

Derek


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## David C (25 May 2010)

Do I remember correctly. Did Adrian say that he was resharpening on a polishing stone only?

This would not remove enough metal to get past the roundness caused by wear.

I like to get a significant wire edge on an 800 stone before moving to the polishing stone.

I also find with an 8 or 10 thousand grit waterstone that there is no need to strop as the wire edge floats off on the stone or the sponge cloth.

Best wishes,
David Charlesworth


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## adrian (25 May 2010)

David C":3gpxsg1m said:


> Do I remember correctly. Did Adrian say that he was resharpening on a polishing stone only?
> 
> This would not remove enough metal to get past the roundness caused by wear.



That's not what I normally do, but I tried it in this case. The puzzling thing is that it seemed to work and the various posts here suggest it shouldn't have.


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## Karl (25 May 2010)

adrian":ytp8dmqq said:


> David C":ytp8dmqq said:
> 
> 
> > Do I remember correctly. Did Adrian say that he was resharpening on a polishing stone only?
> ...



It clearly isn't working if it's taking you 45 minutes to sharpen one blade!!!


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## adrian (25 May 2010)

It took about a minute instead of the normal 10 minutes. Then the blade resumed cutting and cut for at least another 15 minutes.


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## Wiley Horne (25 May 2010)

adrian":yq9trlso said:


> Wiley Horne":yq9trlso said:
> 
> 
> > However, let's set the comparison of planes aside and focus on the bevel up plane. Here's what may be happening….This analysis is based on your observation that the plane stops cutting prematurely; it stops cutting even though it is sharp enough that it should continue with enough applied force.
> ...



No, hardness does not correlate 1:1 with longevity. Abrasive inclusions like silica, as you have said, are a bigger factor. But hardness does matter--note difference between American cherry and canary wood. And it particularly matters when you're attacking at a high angle. As you go from an attack angle of, say, 40 degrees, up to, say, 65 degrees, the mix of penetration versus scraping heavily favors penetration at 40 degrees. But the closer you get to 65 degrees, the more the mix is shifting toward scraping, and especially so as the blade begins to lose a little of its edge off the stone. At 59 degrees, I feel hardness matters quite a bit. You could check this by testing your 59 degree plane on cherry vs. canary wood--does the edge last longer on cherry? 

Wiley


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## adrian (25 May 2010)

Derek Cohen (Perth said:


> Hi Adrian
> 
> First of all I do think that your expectations of 59 degrees versus 45 degree cutting angles needs to be revisited - there is no way that they will perform the same. The edges do not enter the wood (cut) in the same way, and the abrasive properties of the wood act differently upon them.



I wasn't aware of such a big difference in performance with the previous timber I worked (cherry). So I was surprised. If the answer is simply that high angle cutting requires more frequent sharpening that's a fine answer. 



> Question - On the BU blade, are you honing a full face or a secondary bevel?
> 
> The length of time (45 minutes or 50 strokes) it takes you to hone an edge suggests that you are honing a full face, or a wide secondary bevel, or using too fine a grit. A wide bevel is very inefficient. I take about 2 minutes from start to finish (just a couple of strokes on each stone). I only work a micro secondary bevel. I only use a 25 degree primary bevel. Anything over that will create more metal to remove, especially if you add a camber. Cambering a micro secondary bevel takes very little time.



I'm honing a secondary bevel and then applying a tertiary bevel. The secondary bevel has grown kind of large, I observe. It's about 3mm. I tried to estimate the size of the camber. It looks about 1/3 mm, which is smaller than my intention. I'm not sure if that means the camber has been vanishing in use. (I think my target was 0.8 mm, equivalent to the 1/4 mm recommended by Charlesworth taking into acount the different bed angles.) This kind of limits how small the cambered bevel can be. 



> Secondly, while the Ruler Trick is generally an excellent strategy for users of honing guides or on BD blades, I avoid it on BU blades. The reason is that I want to strop the back of the BU blade as I work. I do this freehand. The micro back bevel of the RT makes this strategy very difficult, if not impossible. Although the back bevel angle is so small that I doubt it decreases the clearance angle significantly, the back of the blade is now no longer coplanar and I will not be able to reach the back of the blade by running it on the strop. Stropping likely minimises the incusion of a wear bevel, and the edge can be maintained for at least 3 times as long. I might add that I have never experienced the efffects that you described earlier.



I don't understand. Are you applying a back bevel by stropping? (And didn't someone else say stropping was bad in this case?) How does stropping prevent the wear bevel from causing problems?


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## lwilliams (26 May 2010)

Steve Elliott":m8jz6r9m said:


> My secondary bevels are also very narrow but I've made a device using a laser pointer that allows me to measure the bevels to well less than a half a degree. Here's a picture of a freshly sharpened Hock high carbon blade in the device:
> 
> 
> 
> ...



Steve,

I've found your information on cap irons useful and informative but I haven't gone that deeply into your information and don't know much about it. This is mostly because I approach this kind of information with a view tainted by the pseudoscience one finds on sites like Brent Beech's. Brent, Derek and others, IMO, drape their stuff in all the trappings of scientific inquiry but skip the inconvenience of actually following anything close to the scientific method. 

An example is Brent Beech's use of information about the cutting action of diamonds used for lapidary polishing: http://www3.telus.net/BrentBeach/Sharpen/grinding.html#crystal. While the information is probably accurate for lapidary work, it has nothing to do with the cutting action of diamonds in steel. When cutting steel the edges formed by the facets actually take tiny shavings as do the tiny cutting edges of the abrasives of a grinding wheel. Go to your grinder and pick up a pinch of swarf and you'll see what I'm talking about. You won't get a pinch of powder, you'll get a clump of a stringy almost fibrous material almost like a little pad of steel wool. Brent also seems to base most everything on two assumptions--first one can't manage the wear on the flat face of the iron and the other is than one can't keep a sharpening medium flat. I think both are wrong.

Right now we're going through a few days of tuning and sharpening tools before a workshop. Don sharpened a favored rabbet plane that had seen a lot of use since its last sharpening. Because we had discussed this thread this morning he noticed a pretty significant wear bevel on the face and what it took to remove it. Removing that wear took only four strokes on a medium India stone. This stuff is really easy if you pay attention to maintaining everything flat and keeping your stones in good shape.

What happens with all this is that people like Adrian get led down a blind alley trying to achieve sharpness with a blunt faceted edge. It's just not a good approach. I don't have time to retrieve him and all the others from that alley, maybe Wiley can help him. I am curious how many failed corpses lie at the end of the alley but I don't care to go looking.

The other thing is this thread caused me to go borrow one of my partners' copy of Leonard Lee's book. I read it a number of years ago but with it in my hands I can say that Lee's information has been misrepresented in nearly every forum thread I've participated in concerning clearance angles. While the claimed content of Lee's book has been often used as an argument as to why what I've said about clearance angles is wrong, I'm finding it's one of the strongest supporting sources around.

Some of what I found there were the macro-photographs in Appendix 1 dealing with classification of chip formation. In these, one can easily see the cutting edge is below the surface of the surface left by the cut. One can see the spring-back of the wood fibers swarming behind the cutting edge like water behind an oar. It appears as if the clearance angle of the tool used is a pretty constant 15º while the cutting angle varies. It's clear from the photos that even a 15º clearance angle isn't enough with steep cutting angles.


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## bugbear (26 May 2010)

adrian":2gwk32gj said:


> Note that I've never stropped and I currently use the ruler trick on the back.



Since Lee Valley blades have always been "fairly flat", and many of them are now lapped flat, why are you using the ruler?

The ruler trick is a fine way of avoiding the labour of bringing a large, rough area to full polish (I'll call this "blade preparation", in contradistinction to "sharpening"). This can be very laborious if the blade is old, pitted, distorted, or simply very roughly ground (or a combination!).

In these circumstances the ruler trick provides a method of performing repeatable, localised polishing. The repeatability is importantly, since you need to work the back during normal sharpening, if only to remove the burr.

Without the consistancy provided by the ruler trick it would be harder to avoid either leaving some burr, or having the back bevel thicken and grow, in the same way that hand bevels tend to.

BugBear


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## Ikisumu (26 May 2010)

lwilliams":wymdqi03 said:


> What happens with all this is that people like Adrian get led down a blind alley trying to achieve sharpness with a blunt faceted edge. It's just not a good approach. I don't have time to retrieve him and all the others from that alley, maybe Wiley can help him. I am curious how many failed corpses lie at the end of the alley but I don't care to go looking.



Heh, you are very much right in very many ways. Then again, so much of those things you point out are more or less food for thought, if not plain fun for both those who brought them up and for those who read about them. The richness lies within diversity of things as well. 

I can see why you pick up Mr. Beach's assumption as an example. His assumption is nothing more than an assumption on his behalf for he has no actual scientific methods within his reach to transform his assumption into a well-founded conclusion. And certainly in this case the assumption would cease to exist. It does not work that way with useful states of different steels, and seemingly in his case he needs to see it by himself. 

Ok, there is certainly a kind of a problem if merely something of an assumption will suddenly grow a body for itself, only to start squirming along the freeways of the internet. It will be killed out there in the end, but I admit it can take time, too. 



If getting back to the topic, it has already been quite clear for a while now that member Adrian would have use for an actual accomplished live tutor, who would guide him to choose a logical set of sharpening accessories and to apply those in a manner where it consumes the least of time and energy versus sharp enough blade. That kind of crash course would become a nice starting point to keep on developing skills further. 

Samu


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## Derek Cohen (Perth Oz) (26 May 2010)

I wrote ...


> Stropping likely minimises the incusion of a wear bevel, and the edge can be maintained for at least 3 times as long.



Adrian wrote ...


> I don't understand. Are you applying a back bevel by stropping? (And didn't someone else say stropping was bad in this case?) How does stropping prevent the wear bevel from causing problems?



Hi Adrian

I do strop - not to remove a wire edge after sharpening, as I suspect David was suggesting - but instead between sharpenings to maintain the sharp edge. Just remove the blade and run it over a leather strop with green rouge ...






It is not reasonable to strop the microbevel on the bevel face, and so I choose a second best alternative, this being to strop the back of the BU blade. As it happens, however, that is the side where half (or more - if the research is accepted) of the wear occurs with BU blades. 

You ask a good question whether this is equivalent to a back bevel of sorts. I do not know - I am in the process of building my electron microscope and so I shall soon be able to say. In the meantime all I can add is that it works. My BU blades stay sharp a long time and are no more effort to re-sharpen.

Larry wrote of Steve's post:


> I've found your information on cap irons useful and informative but I haven't gone that deeply into your information and don't know much about it. This is mostly because I approach this kind of information with a view tainted by the pseudoscience one finds on sites like Brent Beech's. Brent, Derek and others, IMO, drape their stuff in all the trappings of scientific inquiry but skip the inconvenience of actually following anything close to the scientific method.



Larry, it is amazing how little actual scientific research you can quote of your own. Any at all? Guys like Steve and Brent make an effort to provide _reproducible_ experiments. Now that is a good definition of scientific methodology is my book. What we get from you is rhetoric, which is hardly scientific in any one's book. Stop your usual strategy - when you are struggling to win a point - by going for the person and not the ball. 

Regards from Perth

Derek


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## Ikisumu (26 May 2010)

Hello Mr. Cohen,



Derek Cohen (Perth said:


> You ask a good question whether this is equivalent to a back bevel of sorts. I do not know - I am in the process of building my electron microscope and so I shall soon be able to say.



That certainly sounds like a fun project. If it is based on a commercial frame, there is still a lot of spare parts available for very old models as well. 

Or are you making the frame as well with a special size chamber with rotating crossfeed table with holder for large parts? I so, I think the best source and advice would be found from classic JEOL formats for special SEMs for manufacturing quality control. Furthermore, if it was me into this kind of project, I would seriously consider adding up an EDS/WDS analyzer in it as well. 

However for to examine just surface topographies, I have a reason to propose that an AFM with a mapping software would be perhaps more definitive method in this sense. 


********

As an academic technical research scientist and materials developer in materials sciences (that has really been my dayjob for past 15 years), methods producing repeatable results are in such a simple cases often not that difficult to achieve _locally_ at all. One just needs to be systematic (which is certainly an art in itself). 

But then, to transfer those results of one's research into universal use of others without essential/significant loss of process information can be truly painful to work through. Especially when the issues are based on dynamical interaction of materials, like it is in the case of successful sharpening. 

The first issue is dynamical interaction of interfaces, which is often already a difficult concept to visualize. Then there are essential materials (steel, stone, fluid), which are always reflecting their performance based on their inherent properties and general quality. 

Dynamics, properties, quality. It is a kind of holy trinity, each of them demanding special attention. If attention is paid sufficiently, there will occur developmet of skills. Otherwise there will be only development of experience.

Of course I do know that most people will never have an access to a situation where they could see and try out all of this on their own, instead all what they can do is to only hear about them. In that situation, the best favour what can be done is to explain the thing at hand without any coloration of opinions without foundation. Another challenge in this task is to learn how to connect the necessary terms and idioms with the target audience. The main point after all is to transfer the results. Further development and validation of methods and materials will be then much easier.

Sorry for this off topic. 

Samu


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## Paul Chapman (26 May 2010)

This has now become so over-complicated it's almost embarrassing :shock: How hard can it be to hone a blade :? It takes most normal people a couple of minutes..........

Cheers :wink: 

Paul


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## Ikisumu (26 May 2010)

Paul Chapman":zwv48n13 said:


> This has now become so over-complicated it's almost embarrassing :shock:



It _is_ embarrassing. 

In addition, I still can't believe I felt such an urge to write such a rant I did. That is very embarrassing as well. 

Samu


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## Derek Cohen (Perth Oz) (26 May 2010)

> Derek Cohen (Perth, Oz) wrote:
> 
> You ask a good question whether this is equivalent to a back bevel of sorts. I do not know - I am in the process of building my electron microscope and so I shall soon be able to say.
> 
> ...



Hi Samu

It was a joke. 

However I do have an interest in exploring this area, and I do have a computer-microscope. Not a serious one by your standards - it's a QX3 - but with Steve's help I shall set it up and take a few pics of the dastardly wear bevel in BU planes!  

Regards from Perth

Derek


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## lwilliams (26 May 2010)

Derek Cohen (Perth said:


> Larry, it is amazing how little actual scientific research you can quote of your own. Any at all? Guys like Steve and Brent make an effort to provide _reproducible_ experiments. Now that is a good definition of scientific methodology is my book. What we get from you is rhetoric, which is hardly scientific in any one's book. Stop your usual strategy - when you are struggling to win a point - by going for the person and not the ball.



LOL, do you really believe all this stuff is "scientific research?" Can I suggest you Google "scientific method" and refresh your memory as to what it is?

I've never represented what I write to be anything other than my own knowledge or opinion. I've never dressed my stuff up to be anything other than that and hope I don't ever feel the need to enhance my information by using pseudo-science for credibility.

I do try to offer easy ways for people to confirm what I say as I did in this thread here:



lwilliams":3165ijd6 said:


> ../You can verify this by using a more acute 30º bevel angle and you'll see the edge life is greater. If you had an O-1 iron you could go to a 25º bevel and increase edge life even more....



and here:



lwilliams":3165ijd6 said:


> ...I believe you have a couple middle pitch bevel-down planes. Hone one at 37º and give it a try. You'll find you're experiencing exactly what Adrian is reporting. You're plane will quickly start balking not working like you're used to it working...



and here:



lwilliams":3165ijd6 said:


> ... Go to your grinder and pick up a pinch of swarf and you'll see what I'm talking about. You won't get a pinch of powder, you'll get a clump of a stringy almost fibrous material almost like a little pad of steel wool....



When I have an outside source that backs up what I'm saying, I cite the source and quote it. For instance each time I've quoted _Machinery's Handbook_ on the clearance angles for metal working I've gone back and retyped all the information for the quote. In this case, I've done it so many times that the last time I did it I just typed into my word processor and saved the file. It's real easy to quote now, want to see it again? You've never replied and said just why you think wood requires less clearance than metal.


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## Ikisumu (26 May 2010)

Hello Derek



Derek Cohen (Perth said:


> It was a joke.



Haha, I see.  

Forgive me not catching a good one, for I indeed happen to know a couple of guys who have actually refurbished old SEM frames for their personal uses. They have equipped those with many kind of extra features, too.



> However I do have an interest in exploring this area, and I do have a computer-microscope. Not a serious one by your standards - it's a QX3 - but with Steve's help I shall set it up and take a few pics of the dastardly wear bevel in BU planes!



There is absolutely nothing wrong with QX3. With it, the scratch patterns and the general idea of the topography of the bevel will be presented nicely. All the way down to significant levels, I believe.

However, if possible at all, including a scale in the picture would be the most welcome. For example so many honing stone salesmen tend to present their scratch pattern pictures without a proper scale included, and it just makes the content of the presentation kind of... well, you know.

Samu


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## Derek Cohen (Perth Oz) (26 May 2010)

Thanks Samu, those are good points you raise, and you are a good sport.

Regards from Perth

Derek


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## adrian (26 May 2010)

bugbear":1nw6pob3 said:


> adrian":1nw6pob3 said:
> 
> 
> > Note that I've never stropped and I currently use the ruler trick on the back.
> ...



I'm a little puzzled by this. It looks like first I'm asked why I use the ruler and then the answer is supplied. :?: 



Wiley Horne":1nw6pob3 said:


> If you treat the blade back just like the bevel side, and raise a heavy primary burr on both sides, yes, you will have removed the wear from both sides. But is that actually what is happening?



Well, when I sharpen as suggested by Charlesworth, no. However before I adopted his methods I used to attempt to raise a burr from the back on each stone. I'm not sure how successful I was in general at doing so, especially on the polish stone where the blade would stick....and my stones weren't always (ever?) flat back then. In Harrelson's video on sharpening he recommends flattening the back and then only using the polishing stone thereafter. But I got other advice to the contrary, that the back should be worked each time with a coarser stone to remove wear on the back. And to be honest, I always feel a bit uncertain when I work the back without raising a burr: how do I know if I've worked it the right amount? 

Note that for the topic at hand, I figured that raising a burr on each side would be a quicker alternative to grinding off the bevel of ensuring that any worn regions are removed. 



> Adrian, here is where you're putting your finger on the real problem. As a number of others have said, an efficient method of sharpening is your top priority--then the rest of this bother will go away. My advice, for plane blades and most chisels, is learn to hollow grind. This will change your life for the better in so many ways. Learn to hollow grind right to the edge. Honing becomes trivially easy, and you will embrace sharpening, rather than needing to work around it.



Right to the edge? I have seen people recommend staying away from the edge to avoid overheating it. If I want to hollow grind I'll have to buy a grinder....



lwilliams":1nw6pob3 said:


> What happens with all this is that people like Adrian get led down a blind alley trying to achieve sharpness with a blunt faceted edge.
> 
> Some of what I found there were the macro-photographs in Appendix 1 dealing with classification of chip formation. In these, one can easily see the cutting edge is below the surface of the surface left by the cut. One can see the spring-back of the wood fibers swarming behind the cutting edge like water behind an oar. It appears as if the clearance angle of the tool used is a pretty constant 15º while the cutting angle varies. It's clear from the photos that even a 15º clearance angle isn't enough with steep cutting angles.



I'm wondering what is meant by "achieve sharpness with a blunt faceted edge"? Does this mean I'm not removing the wear bevels? 

Regarding this issue of clearance angles, I'm a bit puzzled by the claim that a clearance angle of 15 deg is required when everybody is using 12 deg planes...and they do seem to cut. Surely this is clearcut experimental evidence that 15 deg is not required. 



Derek Cohen":1nw6pob3 said:


> I do strop - not to remove a wire edge after sharpening, as I suspect David was suggesting - but instead between sharpenings to maintain the sharp edge. Just remove the blade and run it over a leather strop with green rouge ...



How would this procedure be functionally different from doing the ruler trick on the polish stone a stroke or two every so often? Also, if the problem is that I need to remove a wear bevel from the bottom, and everyone says the polish stone can't do the job...why would this? Or to turn it around, is this evidence that the wear bevel isn't as much of a problem as claimed?


So, let me try to focus things a little bit. There are a few different questions circulating in the discussion:

Sharpening:

1. Does my sharpening procedure (however flawed or misguided it might otherwise be) produce a sharp blade or am I producing blades that are somehow defective (not sharp)?

2. What might I change about my sharpening procedure to make it faster, more effective, better, etc., particularly to decrease my reluctance to sharpen sooner rather than later. 

Clearance Angle:

3. What is the clearance angle required for effective work? How does it depend on cutting angle? What happens if it is insufficient? 

Blade performance and expectations:

4. How long should a blade cut for? How does this depend on the cutting angle? 


Now on this list, question 2 is a kind of open ended question that could draw out everyone's personal sharpening scheme. The other questions are of a more theoretical or focused nature. But I'm not sure I detect a consensus in the answers. 

Next my observations and experimental evidence. I have observed that the bevel down 45 deg plane cuts even when it is dull. The bevel up plane at 59 deg cut angle stops cutting when still somewhat sharp, and certainly much sharper than the other blade. Three explanations seem to be available: it has to do with shaving thickness, it relates to loss of clearance angle resulting from a wear bevel, or it is due to the higher cutting angle. 

Tests I can attempt: try to cut a thin shaving with a dull bevel down plane. (Unfortunately I sharpened it...) Use a 47 deg cut angle blade in the bevel up plane and observe edge longevity---clearance angle is the same. 

How big are these wear bevels? I cite some evidence that they must be pretty small. One is that I was able to bring the edge back to life with just a few strokes of the polishing stone. What does this mean? It means that if the wear bevel is responsible for the loss of cut then it must be pretty small, because I must have removed it in 10 strokes on the polish stone. Another observation is that Derek says stropping keeps his edge going for longer. Does this mean stropping removes the wear bevel? (What other explanation could there be?)

If a few strokes of the polishing stone suffice to make the edge cut again, is there a reason to perform a more thorough sharpening? 

I inspected my blade with a 10X loupe. I found it very difficult to draw conclusions. I thought that _maybe_ I could see a bevel on the back side of the blade showing up as a fine line of reflection. I didn't feel like I had much certainty in the observation. If I hadn't been looking for it I wouldn't have seen it. This seems to indicate that the wear bevel must be extremely small. How big does it need to be to show up clearly? On the other hand, the edge did not look to be in great shape. The loupe revealed a few small nicks. The back surface polish has scratches from a coarser grit not fully removed. 

I've stated that I get 15-20 minutes or so of use out of the blade. Several people have said that this is _normal_ for work in a hard timber with a high cutting angle. In that case, everything is as expected, and maybe there is no need to talk about clearance angles or wear bevels. 

I have ground the secondary bevel back to about 1/2 mm and am ready to resharpen.


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## Derek Cohen (Perth Oz) (26 May 2010)

Hi Adrian

If you get 15-20 minutes of planing hardwood, at 59 degrees, then I would say that you are doing just fine. 

What I would suggest, as an experiment, is to return to your original method of polishing the back up to your finishing grit, and thereafter not touching it with anything less (ala Harrelson Stanley) but not add a Ruler Trick. See if there is any difference. Then experience stropping the back of the blade - do so before you begin to experience any dullness. Compare the three set ups you have used. Let us know what you find.

Regards from Perth

Derek


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## woodbloke (26 May 2010)

Paul Chapman":21396rau said:
 

> This has now become so over-complicated it's almost embarrassing :shock: How hard can it be to hone a blade :? It takes most normal people a couple of minutes..........
> 
> Cheers :wink:
> 
> Paul


Paul has salient point. Good grief...sharpen the blade for God's sake and plane some wood! (also meant in jest) - Rob


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## adrian (26 May 2010)

woodbloke":1a5ll20g said:


> Paul has salient point. Good grief...sharpen the blade for God's sake and plane some wood! (also meant in jest) - Rob



I like to understand what I'm doing. If I observe things I don't understand and I just keep working...then I won't learn and my skills won't improve. That is why I ask these sorts of theoretical questions. Yesterday I didn't have much time in the shop (not unusual) and grinding back the blade consumed it all. Today I hope for better things.


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## Sgian Dubh (26 May 2010)

Paul Chapman":3p8rku52 said:


> This has now become so over-complicated it's almost embarrassing. How hard can it be to hone a blade.



With the intent of offering a completely unscientific approach to sharpening, just a hand-me-down technique quite possibly used in thousands of workshops for generations, and for the education of no-one, posting a link to this hoary old chestnut at this point seems apposite. Slainte.


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## Paul Chapman (26 May 2010)

Thanks Richard - some sanity at last :lol: 

Cheers :wink: 

Paul


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## woodbloke (26 May 2010)

Paul Chapman":1oqw7r5m said:


> Thanks Richard - some sanity at last :lol:
> 
> Cheers :wink:
> 
> Paul


Fabulous...a good read as always :wink: :lol: - Rob


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## Mike H (26 May 2010)

I don't believe it, what a palaver!

I have just been to touch up a blade that I blunted a bit this afternoon.

Including making sure the plane was perfectly adjusted, (LN 5 1/2), I just timed it at 2 minutes 40 seconds! 

Most of the time was taking off and putting back, about 30 seconds on 2 grit sizes and a quick flat back.

We live in complicated times!

Mike

8)


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## Derek Cohen (Perth Oz) (27 May 2010)

Well I commend Adrian for discussing his experiences and raising his concerns on this forum. It takes a great deal of courage to admit when one does not understand something, and I respect him for doing so. There are members here who are being less than helpful, in fact downright rude and discouraging. Do you believe that your disparaging remarks will further Adrian's (or other readers) knowledge in any way, or motivate them to risk posting their questions on the forum? 

The issue that Adrian raised is an extremely important one, and I emphasise this for those that lack the insight to recognise what this thread has been about. It is not simply about "sharpening" a dull blade. It is about what happens at the bevel when you use a BU plane blade. 

There has been much theoretical analyses and too little practical investigation in this area to date. While some may argue that this endeavour is only for those with an enquiring mind, and that one should just use the plane, it is the results of enquiry that produces the fruits we serve up in the workshop in the way of improved methodology.

We need guys like Adrian around here. I think that some of you owe him an apology. 

Regards from Perth

Derek


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## Paul Chapman (27 May 2010)

Blimey, Derek, get down off your high horse :wink: The original question has been more than adequately answered and explained, although after five pages of opinions it's probably quite difficult to find now......

Going round in ever-decreasing circles is not helpful, IMHO.

Cheers :wink: 

Paul


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## woodbloke (27 May 2010)

Derek - your input on all matters on the forum is highly valued by myself and others, but these sorts of theoretical threads examining the minutia surrounding sharpening and honing etc simply do my head in. I know that you'll probably say ..."We'll don' t read them then" but I do, unfortunately. 
At the end of the jour, the process ain't difficult and as has been said countless times hereabouts, we all need to find a way that works for the individual...if one doesn't, try something else that does and get planing wood. 
No disrespect was intended to Aidrian (I did say my post was in jest) but after two threads and five pages I'm losing the will to live. 

I'd be a lot more interested to see exactly what Adrian is trying to achieve with the timber - Rob


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## bugbear (27 May 2010)

woodbloke":73v8czid said:


> I'd be a lot more interested to see exactly what Adrian is trying to achieve with the timber - Rob



He's just trying to get it flat (he said so in his first post).

I think the least helpful advice I've ever seen on sharpening was "just rub it on the stones until it's sharp, then use it"

BugBear


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## Ikisumu (27 May 2010)

Yeah I agree it went quite far. The scientific part especially. On the other hand, sometimes common sense needs to be supported by uncommon approaches. 

If someone has a problem in something I see as clear thing as a Finnish vodka, the best way to start solving it is to make him write a list of things and methods he uses, in detail. If it is still not clear, make him chop down the listed details even further.

It's essentially his challenge and he needs to do his own part of his homework by himself. If the problem is real, the reason will eventually appear at least by trial and error. If not, I will personally start to think the poster is either a common troll, or he is really one of those very rare guys who really should have no business with tools and sharp edges whatsoever. However I think member Adrian is neither.

I have followed various discussion threads in different forums where some guy seems to be quite coherent all the way, but still nothing seems to work. Finally after several posts (and picking and whatnot) it was revealed that all of the stages of the work were conducted in proper order, but then one or two of those stages were taken a just bit too far or was done insufficiently, anyway just enough to ruin the entire thing. A beginner guy had no touch-feely on the thing at all, only tried to just follow some method. 

I think member Adrian has/had problem with this that he just honed his microbevel way too far. A microbevel is indeed something like a 30 ... 500 micron wide region at the edge. Making this takes really only a few pushes, some tens of seconds maybe and that's it.

An uncommon sense is quite common after all, isn't it.  

Samu


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## Derek Cohen (Perth Oz) (27 May 2010)

Paul wrote:


> Going round in ever-decreasing circles is not helpful, IMHO.



Paul, we cannot have you getting dizzy. You'll do yourself a mischief! So just don't read the posts  


Rob wrote:


> these sorts of theoretical threads examining the minutia surrounding sharpening and honing etc simply do my head in. I know that you'll probably say ..."We'll don' t read them then" but I do, unfortunately.



Rob, this type of compulsive behaviour is treatable. In the meantime, just don't read them  

Regards from Perth

Derek


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## bugbear (27 May 2010)

(I wonder if Jacob is reading this, and wanting to "contribute")

BugBear


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## woodbloke (27 May 2010)

Derek Cohen (Perth said:


> Rob, this type of compulsive behaviour is treatable. In the meantime, just don't read them
> 
> Regards from Perth
> 
> Derek


Derek, you're spot again...it's called retirement :wink: - Rob


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## adrian (27 May 2010)

Derek Cohen (Perth said:


> The issue that Adrian raised is an extremely important one, and I emphasise this for those that lack the insight to recognise what this thread has been about. It is not simply about "sharpening" a dull blade. It is about what happens at the bevel when you use a BU plane blade.



Many people clearly don't recognize this, but Derek has it right. The question was about why these planes seemed to behave so differently. And the various answers have clarified my thoughts and given me ideas for things I might try to further my understanding. 



ikisumu":1aptvx0a said:


> It's essentially his challenge and he needs to do his own part of his homework by himself. If the problem is real, the reason will eventually appear at least by trial and error.



Trial an error, completely undirected, is a slow way to learn. I'd prefer to at least limit the scope of trials by using the knowledge of others. And when it comes to understanding things that happen at a microscopic level, perhaps it's not effective at all as a learning technique. If all I wanted to do was make more shavings, then I don't have a real problem because I know that if I sharpen the blade it will make shavings again. The problem is more one of an intellectual character. _Why_ do I observe such a big difference between my tools? And does this in the end suggest a way I should change my work practice?

There are some immediate implications for my method of work. In following the Charlesworth method for flattening timber, you're supposed to plane stop shavings until the plane stops cutting. So what am I to think when the plate stops cutting but the straight edge reveals a pronounced bump? It doesn't cut badly, tearing the work, or leaving lines. It just doesn't cut. As far as I can tell it went from nice shavings to no shavings. Understanding that the plane can stop cutting for other reasons that surface concavity is _very_ useful. 

Another implication concerns tool choice. If I can plane for 15 minutes with a bevel up plane or 4 hours with a bevel down plane before I have to sharpen, and I'm satisfied with the quality of the planed surface in either case, then I'd really prefer the 4 hours. (This would be true even if I can sharpen in 2 minutes because sharpening interrupts my flow.) This would present a strong reason to favor the bevel down. Maybe it would be worth double beveling to get higher cutting angles. If it's rather about cutting angle then maybe I need to carefully consider my need for the 59 degree cutting angle, or at least understand the trade off. 

For those who want to hear about actual shavings, I'll report that I sharpened the blade. It took 10 minutes to work past the microbevel and I did more loupe inspections than I normally would to see if I could identify any residual wear bevels anywhere. As far as I could tell the edge looked good without a bevel on either side. I started with a 0.001" shaving and then raised it to 0.002" and finished flattening the board I've been working on. This took somewhere in the vicinity of 15 minutes and if the plane performance changed during that time, I was oblivious to the changes. 

I'm making a side table and this board will be part of the apron. I need two short pieces more and then I'll have the stock preparation completed, and I can begin the joinery. I expected to start in on planing another board for the two short pieces, but the board had a rather large amount of twist, and I ended up getting caught up in the question of whether to cross cut it (to preserve thickness) or use different stock, or forge ahead. (I do also have the problem of planing the table top. It has some scary looking tear out and is 63" x 22".)


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## Harbo (27 May 2010)

I have been far too busy doing some actual woodworking so in a way have followed the advice given and not read it  
Well not fully - but reading the last bit I think a scraper plane needs to be got ready  

Back to the wood 

Rod


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## adrian (27 May 2010)

I must admit that I haven't had much success with my scraper plane in general. I got it to actually cut by following Charlesworth's directions, but it didn't cut for long and I haven't really gotten the feel for adjusting it. What makes the tearout scary, by the way, is that it looks *deep*. There isn't much of it as the boards are generally well behaved except around a few tiny knots where the grain swirls.


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## big soft moose (31 May 2010)

bugbear":z6f3xwmf said:


> (I wonder if Jacob is reading this, and wanting to "contribute")
> 
> BugBear



he is, if you look on the tother side, hes even started a thread about this thread.

mind you i agree with him (oh god is treatment available), and with paul and rob, its a plane blade - just sharpen it and then get on with working the wood.

I suspect that for some here the woodwork is fast becoming an excuse to work up these incredibly complex sharpening methodologies and theories.

my take is the old saw that good enough is good enough, but perfect is always a pain in the ass.


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