# The secret to cambering Bevel Up plane blades



## Derek Cohen (Perth Oz)

My friend Larry is adamant that bevel up planes cannot be cambered as easily as bevel down planes

_“… for the low angle blade profile to have the same projection as the common pitch plane it would have to have more than three times as much camber…”_

Larry has a point. My own experiments have shown that BU planes require more camber than BD planes. It is for this reason that cambering BU planes has been considered a weakness in the design. Hopefully we can put an end to this view now. The fact is it is dead easy to camber a BU blade … it still will require a larger camber, but this is not a significant issue as long as you follow one simple rule. Let me show you how it is done.

*The Way to Camber Bevel Up Blades.*

Here it is in a nut-shell … grind the primary bevel on all plane blades to 25 degrees. Don’t try to camber any blade that is greater than this, such as one with a 38- or 50 degree primary bevel (such as those available as optional purchases through Veritas). The latter blades are perceived to be a shortcut to honing, but this is an illusion. 

BU planes blades are best prepared with a microbevel. There is no difference if this is added to a 25-, 35, or 45 degree primary bevel. However, the steeper the primary bevel, the more steel to remove when honing/grinding a camber. With a 25 degree primary bevel there is relatively little waste to remove. With a 50 degree bevel … well, you’ll drive yourself insane trying to do so..


*What kind of camber do you want?*

Cambers vary from a .001” thin shaving on a finish smoother to that of the “traditional fore/jack plane used for roughing would have about 1/16" of camber”, as Larry notes. Mmm … can a BU Jack produce a cambered shaving that thick? Easy-peasy!

To illustrate that there is very little extra effort in preparing the camber on a (bevel up) Veritas Low Angle Jack compared to, say, a (bevel down) Stanley #5 ½, I prepared the following tutorial.

*What I do*

The first step is to start with a blade with a 25 degree primary bevel. I do my flat grinding on a belts sander on which I built a jig similar to a Tormek (this was published in a past FWW magazine). If I have to remove a lot of metal, I will use a 40 or 60 grit belt. This runs quite cool.








Here is an example of a 25 degree straight grind on the belt sander …






The second step is to construct a template for grinding the camber. 

Prepare a block of wood the same width as the blade and mark off 1/16” at each end, then draw an arc across this. Remove the waste, so ….








Mmmm… I think I took off a bit more than 1/16”. Looks like 5/64”.

The completed template looks like this ..







and







Adjusted to grind a 25 degree bevel, it works like this …







The result is a cambered 25 degree primary bevel ….







And, yes Bugbear, the camber does indeed match the template! Look …







*Honing the Secondary Bevel*

The aim is now to add a secondary microbevel of 35 degrees. This will create an included angle of 47 degrees, which is close to the 45 degrees of the typical bevel down cutting angle. 

To do this I used a Veritas Honing Guide Mk II (with camber roller) and Shapton waterstones.

The honing guide requires a little modification. Draw a line at the blade stop to help determine the 35 degree setting. Users of this honing guide will understand this instruction. 








The Shapton waterstones used were, in order, 1000/5000/8000/12000.







Here is the microbevel that was produced …







And here is the camber as seen from the mouth of the LA Jack …








Soooo .. what about the shavings? None of this means anything without any shavings ..

Here is a thinnish shaving …







… and a thickish one …







It is possible to go thicker still, but I did not do so here.

Instead, I took some pictures of cambered shavings on other BU planes….

This is one on the Veritas BU Jointer on the edge of a pine board. Look at the thick center and the tapered edges. The shavings are identical to those taken by a cambered Stanley #7. I am sure that David Charlesworth would be proud.








And here is a finely cambered smoother shaving…. Tasmanian Oak planed by the Veritas BU Smoother. 









What is relevant to note about these last two shavings is that the secondary bevel on each is 50 degrees. Further, these were created without a template – simply by extra pressure on the edge of the blade. 

Following the 25 degree primary bevel preparation on the belt sander, the honing guide was set for a 50 degree micro secondary bevel. Ten strokes on the 1000 were enough to create a wire edge across the bevel face. An extra 5 strokes each side was sufficient to create the camber for the smoother, and 10 strokes for the jointer. The 5000 followed with 10 strokes to center, left and right. Ditto 8000 and 12000 ‘stones. The wire edge was removed on the 12000. 


*In conclusion*

I agree with friend Larry that the camber on a BU plane needs to be steeper than on a BD plane. However I do not view this to be a negative factor. It is just a difference in honing, and one that one just accepts as part of the honing method when using these planes. When the secondary microbevel is added to a 25 degree primary bevel, the effort level is low. Camber away without fear.

Regards from Perth

Derek Cohen
October 2007


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## Chris Knight

Nice job Derek. It is a fearsome looking camber I must say (practically a scrub plane) and the shot of the mouth makes it look even more pronounced - although that might just be a shadow effect.

Still the shavings speak for themselves - especially the last picture of Tasmanian oak.

Thanks for the useful guide.


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## Philly

Excellent -thanks for taking the time to document this, Derek!
There has been quite a debate recently on bevel up planes, some folks writing them off as the Devils' Planes! :roll: Needless to say, the results speak for themselves, though.
Best regards
Philly


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## Wiley Horne

Derek,

Excellent method! And fine exposition and photos, too. Would work well for any blade, BU or BD, it appears.

I have one question. When it comes time to resharpen, what do you recommend....just regrind the primary bevel enough to get past the wear on the back side? Or do you operate directly on the back side to deal with the wear?

Thanks, Wiley


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## Paul Kierstead

Excellent illustration and article! I am glad someone is addressing this and making straightforward and accessible.



> Here it is in a nut-shell … grind the primary bevel on all plane blades to 25 degrees. Don’t try to camber any blade that is greater than this, such as one with a 38- or 50 degree primary bevel (such as those available as optional purchases through Veritas). The latter blades are perceived to be a shortcut to honing, but this is an illusion.



It is very nice to see this re-enforced. I really think people get too caught up on the primary bevel.


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## Derek Cohen (Perth Oz)

> When it comes time to resharpen, what do you recommend....just regrind the primary bevel enough to get past the wear on the back side? Or do you operate directly on the back side to deal with the wear?



Hi Wiley

You have asked the Big Question. The short answer is that I am not certain, and I have two areas to explore.

When it comes to sharpening, I much prefer a hollow grind on a grinder, followed by freehanding on waterstones. This is clearly very different to the above process but it is my preferred method for BD blades and chisels. Further, I would like to avoid a micro back bevel (such as the Ruler Trick) - not because I disaprove of it. I think it an excellent technique under other circumstances - because I like to strop blades as I work, and this is difficult to do with backbevels, both front and back. 

So my first impulse is to follow this with BU blades. That is, hone the back of the blade sans micro backbevel. The trouble is that BU planes create wear on the back of the blade, and the question is how does one get rid of it?

One could just regrind the primary bevel and add a new microbevel. But this seems a lot of work and wasteful of steel. 

One could flatten the back of the blade, for example, by regular stropping as one works. This is what I am doing at present, but I am still evaluating how well it works. My concern here is that one may inadvertantly over time be creating a curved back.

The other alternative is to deliberately add a micro backbevel (using DC's Ruler Trick), as this will circumvent the wear bevel. I have done this in the past, and it works, but it means that I cannot strop the back of the blade (to refresh the edge). 

So sorry no definite answer as yet. All the above work. The question is which one works to provide the greatest efficiency. I hate sharpening and all I want is to find a simple and efficient method.

Regards from Perth

Derek


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## David C

Derek,

Nice shavings, proud indeed ~;-)#.

For resharpening I would suggest you have a look at my plane sharpening dvd. Your method above is getting very close to my sharpening routine except I use a £5 guide and only two stones, 
Coarse 800 king and polishing 8,000 or 10,000 grit King.

The use of 2 stones only is made possible by the two degree lift when moving from coarse to polishing on bevel.

Re sharpening is just a case of how many strokes does it take to get a tiny wire edge in the centre, where most wear will have taken place. And then applying same number of strokes to the four other points across the blade.

Shaping and resharpening get even easier if you grind at 23 degrees.

Wiley,

When regrinding, leave a sliver of the previous honing as this contains the shape or squareness of the edge. There is no reason to grind up to the edge unless you have a big chip. This just shortens life of blade.

Despite the fact that so many are suspicious of it, the ruler trick works for all edge tools except bench mortice & paring chisels.

*Please forgive a small rant here. * I am fed up with the few rude and obnoxious people on knots forum who mock and misrepresent my methods without even taking the trouble to understand them.
The intellectual effort required seems to be beyond them?

*This forum is generally a much pleasanter place to post *~#

best wishes,
David


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## Philly

David C":3q8ga7gp said:


> *This forum is generally a much pleasanter place to post *~#
> 
> best wishes,
> David



That's just how we like it, David!  
Philly


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## Derek Cohen (Perth Oz)

Hi David

Thank you for the vote of confidence. And, yes, this is a much more civilized and friendly atmosphere than some others! Do not go There (you know where) if you suffer HBP. 

Incidentally, the reason I have used 4 stones is more a case of "new stones and getting to know them". I previously would do a 1200 and 8000 King. These Shaptons are just great for the feedback they provide. I am indeed familiar with your sharpening video - own it and have watched it many times. Where do you think I learned to hone cambers by numbers?  

I took a few more shavings with the LA Jack (my previous effort there was to demonstrate the process and I stopped short of deep, fore-plane-type shavings). These now were about 1 1/4" - 1 1/2" wide and 1/32" thick. 






Regards from Perth

Derek


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## dchenard

Derek Cohen (Perth said:


> Here it is in a nut-shell … grind the primary bevel on all plane blades to 25 degrees. Don’t try to camber any blade that is greater than this, such as one with a 38- or 50 degree primary bevel (such as those available as optional purchases through Veritas). The latter blades are perceived to be a shortcut to honing, but this is an illusion.
> 
> BU planes blades are best prepared with a microbevel. There is no difference if this is added to a 25-, 35, or 45 degree primary bevel. However, the steeper the primary bevel, the more steel to remove when honing/grinding a camber. With a 25 degree primary bevel there is relatively little waste to remove. With a 50 degree bevel … well, you’ll drive yourself insane trying to do so..



Not sure I understand here... 

It seems to me that if you put a heavy camber on a 25 degree iron, you will have a lot more steel to grind away than with a 50 degree blade. Just look at the length of the bevel... Not that one would want to put a heavy camber on a high angle iron (after all a plane using that heavy a camber is for roughing anyway), these are for final smoothing and therefore should have minimal camber.

As for irons with a high primary bevel (38 and 50 degrees), these are not a shortcut to honing if you do it freehand. But if you want to put a 35 degree micro-bevel on a 25 degree blade, you have no choice but to use a honing jig... Wouldn't you know, I've found one advantage of using a honing jig! :shock: :mrgreen:

Still, I prefer honing freehand (not the topic here, so I'll keep it at that) :wink:

The other DC


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## Derek Cohen (Perth Oz)

Denis

Trying to camber a 50 degree full face bevel is very hard work. There is considerably more steel to remove than when the primary bevel is a low 25 degrees and a 50 degree secondary bevel is added.

I spent a long time fighting with this area. I much prefer honing freehand on a hollow grind. This is fine for bevel down planes and for most chisels. It is also still the method I employ for low angle bevels on BU planes, such as the LA Jack when used on a shooting board (straight bevel) and across grain for flattening panels (slightly cambered bevel). An example of the latter is below:






On the other hand I use high cutting angles - 50 degrees bevels for a 62 degree included angle - when smoothing or jointing as the timber I work is hard and has much interlinked grain. It is simply impractical to freehand these blades, and so I have come to accept that these must be created with microbevels using a honing guide. 

If you want to freehand a 50 degree bevel, go ahead - it can be done (I have done it) - but you are essentially restricted to a straight edge. Adding a camber to a 50 degree bevel face would take you hours to do freehand, and then you are faced with the "fun" of maintaining it. 

Regards from Perth

Derek (one of the DC club)


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## dchenard

Derek Cohen (Perth said:


> Denis
> 
> Trying to camber a 50 degree full face bevel is very hard work. There is considerably more steel to remove than when the primary bevel is a low 25 degrees and a 50 degree secondary bevel is added.



This is the part that I don't get... A 3/16" thick iron has a bevel that's 0.443" long at a 25 degree angle, and 0.245" with a 50 degree angle. Seems to me there's nearly twice as much steel to remove on a 25 degree bevel iron compared to a 50 degree one, for a given camber angle. Either your statement is incorrect, or I'm missing something... 



Derek Cohen (Perth said:


> I spent a long time fighting with this area. I much prefer honing freehand on a hollow grind. This is fine for bevel down planes and for most chisels. It is also still the method I employ for low angle bevels on BU planes, such as the LA Jack when used on a shooting board (straight bevel) and across grain for flattening panels (slightly cambered bevel). An example of the latter is below:
> 
> On the other hand I use high cutting angles - 50 degrees bevels for a 62 degree included angle - when smoothing or jointing as the timber I work is hard and has much interlinked grain. It is simply impractical to freehand these blades, and so I have come to accept that these must be created with microbevels using a honing guide.



Impractical? Not really, how is that so? Is it more difficult to put a microbevel freehand on a steep beveled iron than on a low bevel one? Yes, but it can be done without too much trouble.



Derek Cohen (Perth said:


> If you want to freehand a 50 degree bevel, go ahead - it can be done (I have done it) - but you are essentially restricted to a straight edge. Adding a camber to a 50 degree bevel face would take you hours to do freehand, and then you are faced with the "fun" of maintaining it.
> 
> Regards from Perth
> 
> Derek (one of the DC club)



Why is it that one is restricted to a straight edge if doing a 50 degree iron freehand? Not trying to start an argument, just trying to understand, as I do use a gentle camber on my 50 degree iron, and do the micro-bevel freehand... Not as easy as with a lower beveled iron, but doable, the technique is the same...

Cheers,

DC-C (for Canada)


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## Wiley Horne

Hi Denis,

I believe Derek's point about grinding camber on the steeper-angled blade is that you're getting far more quickly into the meat of the blade. In other words, this is solid geometry, not plane geometry. You're grinding the same linear distance, say 1/16", regardless of bevel angle. But with a 25 degree blade, the camber takes you ankle deep into steel; with a 50-degree blade, you get up to your knees, and quickly.

However, I like where you're going with your inquiry. Caution: opinion follows......It strikes me that the best compromise on dealing with 12-degree BU blades is simply to take enough metal off the primary bevel each time to remove the wear mark on the blade back. In the overall tradeoff--with 12 degree blades--I would prefer to maintain as much clearance as possible, and sacrifice metal to do it. Now if it were a 22.5 degree Holtey BU, I think I would prefer to work the back directly, because of the greater clearance available. 

I think Derek is almost there in his method. The key is to remove steps from the resharpening procedure. One way to do this would be, as Derek says, to make the first grinding at 25 degrees. And do the microbevel thing. But on the first resharpening, go back to the grinder and grind to 35 degrees, skip the microbevel, and freehand hone. On subsequent resharpenings, go back to the grinder and remove enough metal (est. approx. 0.001" of primary bevel) to clean up the blade back, and freehand hone. 

The belt sander is a good procedure, and Derek's setup looks to be very fast. In my case, I hollow grind cambered blades freehand on a simple vertical bench grinder, and that will work also.

I agree with you that freehand honing cambered blades and gouges is simply a matter of practice. You develop the feel and the rhythm, and it goes quickly once you've done that.

In short, I think Derek is about there, and that he need only rely more on grinding in subsequent resharpenings, after the initial setup.

Wiley


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## AHoman

David C":3osyi2r5 said:


> *Please forgive a small rant here. * I am fed up with the few rude and obnoxious people on knots forum who mock and misrepresent my methods without even taking the trouble to understand them.
> The intellectual effort required seems to be beyond them?



David, 
One of the primary objectors to the ruler trick is the same fellow who a few months ago deplored the use of shooting boards, claiming that if one couldn't just put a board in a vise and plane to a line, then one should probably just use power tools before resorting to a shooting board.

Some of these people who object so strongly to shooting boards and the ruler trick are borderline trolls who have never posted pictures of their work to back up the notion that anyone should take their opinion any more seriously than mine (I am a rank amateur).

In my recent adventures in woodworking, I have enjoyed again and again the accuracy that I get from the use of shooting boards as outlined in your books. I've used the ruler trick on occasion, but I've also learned to prepare the backs of irons in a more traditional manner. 

It is invaluable to my continued search for ways to make the most of my brief woodworking time that I can occasionally read posts by you on these forums. Please don't leave! For every close-minded soul there are probably 10 or 15 who admire your contributions and just read the posts but don't get mixed into the fray by posting, especially on Knots. 

I'd like to tell a story about the influence that your publishing has had in the world. 

I started reading your books in January 2006. I teach (humanities and German) at a school that has a woodworking component to its sculptural arts program. In tenth grade the students usually make some kind of project with dovetails, usually a small stool or box. I showed your books to my colleague who teaches sculptural arts, and he almost immediately decided to build shooting boards for the students, and to tune up our fleet of Stanleys with Hock irons. Just for fun, during my free periods I've assisted him twice with this six week lesson -- the second one is 3/4 of the way through and we are having a blast. The students use the shooting boards to prepare their boards to make small dovetailed boxes out of cherry and walnut. They love using the shooting boards, and we feel that it is a safe way of letting them prepare their own boards for the project. Someday, we're hoping that a particularly inspired group of students will want to take a special elective and make something with twisted dovetails! At any rate, your publications have been an inspiration for our tiny little school in rural Vermont, thousands of miles away. We have one student who is interested in furniture design and would like to take a gap year (that is a year between high school and college) in England to explore this passion -- he is looking into a variety of programs.

Sorry for going on for so long, but when I read the discouraged note in your email, I felt that I had to pipe in some encouragement.
Best regards,
Andy


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## dchenard

Wiley Horne":2ym596kb said:


> Hi Denis,
> 
> I believe Derek's point about grinding camber on the steeper-angled blade is that you're getting far more quickly into the meat of the blade. In other words, this is solid geometry, not plane geometry. You're grinding the same linear distance, say 1/16", regardless of bevel angle. But with a 25 degree blade, the camber takes you ankle deep into steel; with a 50-degree blade, you get up to your knees, and quickly.



Hi Wiley,

Pardon me for being insistent, but the statement that one will remove more steel on a 50 degree bevel than on a 25 degree bevel just plain doesn't work. Do the geometry: in an ideal world one will remove nothing at the middle of the iron, and go gradually to a camber of say, 1/16", same for both irons. Except at the middle where one removes nothing, at every other point on the curve you will remove more steel with the 25 degree bevel than with the 50 degree bevel iron. Compute the cross-section of the metal to be removed, you will see for yourself, the 25 degree iron needs 0.00277" of cross-section removed at the edges of the iron, whereas the 50 degree bevel one will require 0.00153" removed, or just a tad more than half as much as for the 25 degree bevel. And at any point on the camber more metal will need be ground off from the 25 degree bevel. 

I have no qualms about the rest of the post, I do actually like it. I use a different approach in honing my irons, which I think is more efficient, but to each his own. It's just the statement that more steel is removed from a 50 degree bevel compared to a 25 degree bevel one just doesn't work. I'll be happy to be proven wrong, but I don't think I will, sorry to say...

Cheers,

DC-C


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## Wiley Horne

Denis,

I'll write you offline, as I have unwisely jumped into the middle of Derek's story with an explanation--when he is infinitely more qualified than I to explain his results! 

Wiley


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## Derek Cohen (Perth Oz)

Hi Denis

Let me start by saying that your questions are good ones. Even more than good - they are important and must be asked and answered. 

The problem centres around the grind (a term I prefer when removing metal rather than polishing it) a _significant_ camber on a bevel up blade. And to take this the important next step, to do so on a BU blade with a high bevel face, such as 50 degrees. 

It is contended generally that a BU blade requires a greater camber for the same effect than a BD blade. This is due to the geometry of the bed, 12 degrees for BU and 45 degrees for BD. 

It is my contention that there is less metal to remove - which makes the process viable - on a BU blade with a 25 degree primary bevel and a 50 degree _secondary (micro)_ bevel. The foundation for this argument is that a microbevel is .. well, micro .. and a camber on the _full face _of a 50 degree primary bevel has considerably greater volume.

I would suggest that you try cambering a full face 50 degree bevel by hand and, if you can, do the same with a 50 degree micro secondary bevel on 25 degree primary bevel , and report back your experience.

Keep in mind that we are talking about creating shavings for not just a smoother, but especially for a fore plane - so see the camber profile that is needed to do this. The camber resembles that of a scrub plane with a BD configuration.

Regards from Perth

Derek


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## David C

Andy,

Thank you so much for that encouraging story!

David


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## AHoman

David C":qnerpqap said:


> Andy,
> 
> Thank you so much for that encouraging story!



Now we will just have to see what Derek's influence will be on our woodworking program -- will it be bevel-up planes, or will we have the kids make their own dovetail markers? (Or will I have them read Viktor Frankl?)
-A.


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## promhandicam

dchenard":c32fdxkz said:


> Pardon me for being insistent, but the statement that one will remove more steel on a 50 degree bevel than on a 25 degree bevel just plain doesn't work. . . . Cheers, DC-C



Having read through the whole post, I think that, in your own ways both Derek and Denis are correct. 

In the initial set up of converting a blade from straight to cambered then yes more steel has to be removed if you are grinding a 25 degree bevel as opposed to a 50 degree bevel. However once the basic shape has been produced, when it comes to sharpening, less steel will be removed if you add a secondary bevel onto a 25 degree primary bevel than if you are trying to hone the whole of a 50 degree face. Perhaps the following will illustrate what I'm trying to say:






The red lines indicate where the iron would be honed to get a 50 degree angle.

I hope this helps,

Steve


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## ivan

I understood Derek to mean "metal removed on the honing stone". If you have a 25 deg primary bevel you don't have to remove much steel to hone it - it's a microbevel, even if honed at 50 deg. If you grind at 50 deg, you then have to remove metal from the whole face of the bevel to hone it (also at 50 deg). This right?


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## dchenard

promhandicam":3h3ehsbv said:


> In the initial set up of converting a blade from straight to cambered then yes more steel has to be removed if you are grinding a 25 degree bevel as opposed to a 50 degree bevel. However once the basic shape has been produced, when it comes to sharpening, less steel will be removed if you add a secondary bevel onto a 25 degree primary bevel than if you are trying to hone the whole of a 50 degree face.
> 
> I hope this helps,
> 
> Steve



Totally agree. Might be the term selection (grinding/sharpening/honing) that created the confusion...

Blame it on a language difference, as neither Derek nor I have English as their first language :lol: 

I'll get my coat now :mrgreen:

DC-C


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## Derek Cohen (Perth Oz)

Steve

Thank you for clarifying that point. It is amazing in how many ways the same sentence might be (mis)interpreted.

Here is what I originally wrote:



> Here it is in a nut-shell … grind the primary bevel on all plane blades to 25 degrees. Don’t try to camber any blade that is greater than this, such as one with a 38- or 50 degree primary bevel



Regards from Perth

Derek (who is indeed bilingual, but admits that he has no excuses as English is his first language)

The DC Club


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## dchenard

promhandicam":22qpha7f said:


> dchenard":22qpha7f said:
> 
> 
> 
> Pardon me for being insistent, but the statement that one will remove more steel on a 50 degree bevel than on a 25 degree bevel just plain doesn't work. . . . Cheers, DC-C
> 
> 
> 
> 
> Having read through the hole post, I think that, in your own ways both Derek and Denis are correct.
> 
> In the initial set up of converting a blade from straight to cambered then yes more steel has to be removed if you are grinding a 25 degree bevel as opposed to a 50 degree bevel. However once the basic shape has been produced, when it comes to sharpening, less steel will be removed if you add a secondary bevel onto a 25 degree primary bevel than if you are trying to hone the whole of a 50 degree face. Perhaps the following will illustrate what I'm trying to say:
> 
> 
> 
> 
> 
> 
> 
> The red lines indicate where the iron would be honed to get a 50 degree angle.
> 
> I hope this helps,
> 
> Steve
Click to expand...


Time for a mea culpa  

Looks indeed like I did not interpret Derek's statement properly. As exposed here by Steve, I do not have any argument.

Furthermore, and this is where I must admit being red-faced, in my example where one grinds a camber on the whole face of a 25 degree bevel iron versus the same on a 50 degree iron, I've maintained that the 25 degree iron will require more metal being removed in order to form the same camber. Thanks to Wiley, I must admit that I was wrong #-o 

In fact, no matter what the bevel on the iron, grinding a camber on the whole bevel of an iron will result in *the same amount of metal removed*, no matter what the bevel angle.

The point that I neglected was that, as the bevel angle goes down, the "effetive thickness" of metal removed to produce a camber goes down at the same time that its length goes up. Think "long and thin" versus "short and fat".

Definitions:

BLT: blade thickness
BET: "effective thickness" of metal removed
BL : bevel length
C : camber of the blade 
(theta): bevel angle of the iron

The equations go like this:

BL = BLT / sin (theta)

BET = C sin (theta)

The section of metal removed at any point over the width of the blade is a parallelogram in section, which area can be computed as a rectangle of length BL and thickness BET. Multiplying the two, we get:

Section = BL * BET = BLT * C

Notice that the angle of the equation get cancelled out, or in other words, the bevel angle has no bearing on the amount of metal being removed, only blade thickness and amount of camber matter.

Thanks to Wiley for clarifying this ccasion5: 

DC


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## ivan

PS. I assume there's little advantage in using the JET cambering jig? This one looks a good deal more affordable....


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## David C

Ivan,

I have been using that New Jet jig, (which fits Tormek) and have written about it and camber in general, in the issue of F&C which is out about now.

It does a very good job on gentle and medium camber, may or may not do enough for a scrub plane, didn't have time to find out.

I like it a lot.

David Charlesworth


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## ivan

Thanks, David; I'll keep a lookout for the mag. but newsagents are a rare item in these 'ere parts.


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## David C

Ivan,

There is one at the bottom of Bideford high street!

Where are you?

David


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## bugbear

Derek Cohen (Perth said:


> The result is a cambered 25 degree primary bevel ….
> 
> 
> 
> 
> 
> 
> 
> And, yes Bugbear, the camber does indeed match the template! Look …



I never denied that it would; my point was, and remains, that the blade camber is generated by your skill and care, not the template.

None of which is to deny the demonstrable fact that your procedure generates the blade you desire.

BugBear


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## David C

BB,

I was going to point out the same thing.

The skill required is to keep the long stick at the same angle.

A support at the top end of the stick would help to maintain consistent angle, would it not?

best wishes,
David


----------



## bugbear

David C":w3aew68z said:


> BB,
> 
> I was going to point out the same thing.
> 
> The skill required is to keep the long stick at the same angle.



No., that all works fine. The bevel angle is maintained by the distance from the blade tip to the template resting on the guide bar.

It is the notion that the template (end) shape generates a matching camber that I take issue with.

It is (IMHO) obvious that simple leaving the blade in the central position would result in a simple square end. Indeed, leaving the blade in any one position would result in a splendid "flat", and this could be done at any position.

From this it follows that the desired curve is not being _constrained_ by the template, but only _allowed_. As such, I claim that any "template" e.g. a simple point (or small radius'd end e.g. 10mm) would work just as well.

BugBear


----------



## promhandicam

I agree with BB that the way that Derek has produced the camber isn't dependant on the form of the wooden template. The only way of using a template like that to reproduce the same form on the blade would be to have a set up similar to that used in key cutting - i.e. a stylus running against the template and using a thin grinding disk - it wouldn't be possible to do it using a belt sander setup. 
If you look closely at the photos of the cambered blade, you can see that the striations are not parallel but that they radiate out from the centre indicating that the blade was pivoted around a central point which as BB says could just as easily be a small radius. What is more critical in producing the desired camber is the distance from the pivot point to the grinding surface (to give the desired curve) and the height of the pivot point above the grinding surface to give the angle of the camber. 

Maybe a better jig for those who aren't as skilled grinding / using a belt-sander would be something similar to this: 





Steve


----------



## sparky

Well I'd like to ask a quick question :roll: 

If someone sharpened just by hand (I do it that way with waterstones) isn't the higher bevel angle easier to work with since it is closer to the final angle. 
It seems to me that this whole discussion presumes that the blades are initially ground mechanically. Which is fine, but I was curious about BU blades done by hand. 
Also when I say by hand I mean freehand, (without a honing guide) which is a goal of mine to learn. 
If anyone has any ideas, I appreciate it.

Sparky


----------



## David C

Sparky,

For pure hand honing I think you might like the Krenov method.

The grinding is done at the same angle you want to hone at.

The hollow grind then sits nice and stable on an oilstone.

Honing polishes both the heel and the tip of the bevel.

However once much of the bevel is honed and flat, it takes a long time to remove enough metal to resharpen....

So JK returns to his hand cranked grinder to start the cycle all over again.

David


----------



## David C

Steve,

I show a concocted jig which works something like your diagram on Page 50 of my second book.

I wanted to convert wooden Jack planes to hollowing planes (a GREAT idea from the Alan Peters book, a scandal that it is no longer in print) and designed the jig to give a fixed radius without any skill or feel involved. i.e. almost totally repeatable.

BB has summed things up rather nicely, as usual, the Derek jig involves some skill and feel, which he clarly has, judging by the nice looking results.

David


----------



## sparky

Thanks Mr. C and all

So here is my next question. Since I am completely "cordless" :roll: where could I find a hand-powered grinder?

sparky


----------



## Derek Cohen (Perth Oz)

> For pure hand honing I think you might like the Krenov method.
> 
> The grinding is done at the same angle you want to hone at.



Hi David

That is what I do with the BD blades and chisels. It makes freehanding a blade very easy.

To set the bevel angle/hollow I use the Tormek jig on a bench grinder.






Regards from Perth

Derek


----------



## woodbloke

David C":20w71b4r said:


> Steve,
> 
> I show a concocted jig which works something like your diagram on Page 50 of my second book.
> 
> I wanted to convert wooden Jack planes to hollowing planes (a GREAT idea from the Alan Peters book, a scandal that it is no longer in print) and designed the jig to give a fixed radius without any skill or feel involved. i.e. almost totally repeatable.
> 
> BB has summed things up rather nicely, as usual, the Derek jig involves some skill and feel, which he clarly has, judging by the nice looking results.
> 
> David



I recently made one of David's jigs for grinding curved blades on a Tormek and it works very well...agree again about Alan Peters book (of which I have a copy), one of the very *best* books on woodwork that you will find anywhere - Rob


----------



## ivan

Yes, it's true that if you didn't move the blade, you'd get a straight(ish) edge. That's also true for a standard straight jig. ??! you say? The point is you have to slide even a straight jig from side to side whilst grinding, either to even out wear in the stone, or because the blade's wider than the wheel. Despite the helpful jig, it's still a 'hand' process needing a bit of skill. 

If the camber was produced by the template acting just as a point pivot, the camber would have a rather extreme radius of about 2". From Derek's description and photos, he _rolls_ the template back and forth on the rest. If the edge follows the template, he must do this for about the same number of revolutions at each point. (a bit like DC's camber honing) In practice a steady roll back and forth should do the trick.

I'm assuming that any required _precision_ (straightness, skew, match edge of cap iron etc) can be obtained at the first honing?


----------



## Derek Cohen (Perth Oz)

> From Derek's description and photos, he rolls the template back and forth on the rest. If the edge follows the template, he must do this for about the same number of revolutions at each point.



Hi Ivan

That is exactly what I do. 

I wish I could take a video to reveal the technique. Yes, there is handskill involved (I'd like to believe that!  ) but the template is also doing its work to create a specific camber.

Perhaps someone on the forum would try replicatng the template and the action as I described it?

Regards from Perth

Derek


----------



## bugbear

Derek Cohen (Perth said:


> From Derek's description and photos, he rolls the template back and forth on the rest. If the edge follows the template, he must do this for about the same number of revolutions at each point.
> 
> 
> 
> 
> Hi Ivan
> 
> That is exactly what I do.
> 
> I wish I could take a video to reveal the technique. Yes, there is handskill involved (I'd like to believe that!  ) but the template is also doing its work to create a specific camber.
> 
> Perhaps someone on the forum would try replicatng the template and the action as I described it?
> 
> Regards from Perth
> 
> Derek
Click to expand...


There is no doubt your process can generate a cambered blade. I (for one) have no need of third party proof of this.

My continued doubt is that the camber on the template is in any way "generative" of the camber on the blade.

I _know_ that a shallow camber can be made with any pivot small enough to allow the needed swing, because I've done it.

http://www.geocities.com/plybench/scrub.html#blade

In this case, the pivot is the single narrow roller (wheel!).

I believe I've demonstrated (verbally) that your template could (rather easily) make a straight across blade.

So I am at a loss to see why the blade camber should match the template camber, other than operator input (which clearly works)

I would welcome explanations though.

BugBear


----------



## Wiley Horne

I believe Bugbear and Ivan are both correct. Bugbear is correct in that it is operator input that is making the jig work properly. But Ivan has explained that rolling the template along the control bar results in a radius on the blade edge which would require a considerably longer (more distant) point radius. Indeed, one could start with the sagitta = 1/16" and the blade width, and calculate what the equivalent point radius would be, measured along the slant of the primary bevel.

Derek's contribution, as Ivan explains, is that his jig (applied with requisite skill as BB explains!), can produce smaller sagittas without having to use point-pivot jigs with impractically long radii.

Wiley


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## MikeW

The camber produced is slightly larger than that on the jiggy as long as there are no user corrections made, no matter how subtle. That's the physics of it. At least if this were a single-pivot point jig. Here's how I think a single-pivot jiggy would work...

The closer the edge is to the jiggy, the less this offset or difference is. I suspect that without user input the difference on a 2" blade, a 2.5" desired radius, and having a 1.5" projection is about 1.5" difference (a blade ends up with a 4" radius). I believe that same difference in radius holds true using the same projection no matter the start/end radii. At least that's how it seems to my mind. 

But, Derek's jig isn't pivoting on a single point. I think if the point on the jiggy and the edge of the blade are kept relatively square to each other at the point of the blade's contact to the sander/grinder wheel, the blade will end up with the same radii as the jigs used. If I was better at using CAD, I would try to draw it. If I had more time, I would make one to try on a piece of scrap saw steel. If nothing else, it is removing some of the radius "growth" inherent in a single-pivot point jiggy.

The skill comes in by not lingering in one spot longer than another--which is helped by drawing the arc onto the non-beveled side of the blade to be cambered. The jiggy keeps the projection relatively even through the arc (unlike a single-pivot). It still takes operator error to not remove say more in the center than the corners and vice versa.

In one sense, it doesn't matter. The main benefit is that it is reproducable.

Take care, Mike
who only cares that his pattern maker's blades and rounds are accurate--they need to match the soles...


----------



## BrentB

A very interesting discussion, in which I have learnt a number of things about cambered blades. 

The similarity between the template and the blade shape leads one to the conclusion that one can only lead to the other. BugBear has noticed and explained well the weakness of the linkage. People trying this at home could easily get a very different curve. Which means of course, a variable bevel angle across the blade. An arc scribed on the back would certainly help. 

Assuming a rod based tool rest (rather than a flat tool rest at the desired angle), then I think Derek's jig is better than a point jig. If you use Derek's jig and grind to an arc scribed on the back, then the resulting bevel would have a constant included angle. If you use a point in the middle and grind to an arc on the back, you get a variable included angle (smaller away from the middle).

The standard method, assuming you have a belt sander or grinder and an appropriate tool rest, 

1 scribe the desired curve on the back,
2 grind at 90 degrees to achieve that edge shape,
3 grind the bevel at the desired angle just up to the edge,

produces a surer arc faster. Even with a tool rest (which helps with the bevel angle), it would be possible to get a different edge shape without the arc. Grinding to an inscribed arc, then grinding the bevel to that arc, together help to get the desired shape. Trying to do both in one step might lead to a blued edge.

Finally, a question.

An earlier post showed an alternative jig design that was claimed to be better than Derek's design. I cannot see why it is an improvement. Can someone help me on this?


----------



## Philly

Welcome to the forum, Brent.
Good to have you aboard,
Philly


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## David C

Brent,

I did not study the diagram properly, but think it is like the set up in my second book, used to produce blades for a hollowing plane, with curved sole..

The angle is controlled by a fixed sloping plane.

The radius is set from an adjustable but but finally fixed pivot point.

This produces exact repeatable curve without any skill input, or feel from the operator. It could be done with a blindfold on.....

best wishes,
David Charlesworth.


----------



## bugbear

MikeW":15stozr9 said:


> The camber produced is slightly larger than that on the jiggy as long as there are no user corrections made, no matter how subtle. That's the physics of it. At least if this were a single-pivot point jig.



I think an important point is being missed.

All the statements about circles and radii would only be true if the grinding surface were vertical (i.e. 90 degree bevel!!). Under this circumstance, the grinding process would cease for any given distance, allowing the (square) end of the blade to be ground to a camber, in the manner suggested by several people.







On the right we have a grinding belt, the blade is blue, the bar is ref, the template is brown(ish) and the grinding rest is back.

In the upper diagram, grinding cannot proceed beyond the limit set by the template, and thus the template can generate a camber (and the various discussions about shapes and radii are applicable).

In the lower diagram, which reflects the actual situation (with a realistic bevel) grinding can go "too far" by simply making the bevel steeper and steeper, and thus the template cannot "generate" the camber.

BugBear (who continues to point out that Derek's blades come out just fine)


----------



## Paul Kierstead

bugbear":3qgw40sn said:


> All the statements about circles and radii would only be true if the grinding surface were vertical (i.e. 90 degree bevel!!). Under this circumstance, the grinding process would cease for any given distance, allowing the (square) end of the blade to be ground to a camber, in the manner suggested by several people.



With turning tools I have ground the edge vertically to get the shape I want, then ground the bevel using a platform to bring the bevel to the shape; it is very easy to see where you need more/less grinding. All in all, not a bad method. Should work here too.


----------



## MikeW

I too fear the point is lost, BB.

What do we make of the scientist who doesn't try the solution to a problem choosing to rather rationalize why it won't work? Proving or disproving through trial and error is still the scientific method, eh?

In that vien, I went out and tried Derek's jiggy and a single-point version. Both work. The single-point requires more user intervention and changes the bevel angle as it moves to the outer edges. Which makes sense as that is how one produces a fingernail grind on a turning gouge. Derek's jiggy produces an even bevel angle.

The single-point changes the distance from the pivot-point to the edge. The other jiggy does not.

However, there is nothing in Derek's jiggy (or the other) to prevent one from over grinding and thus changing the desired camber. That part is user experience.

The solution to that "problem," it seems to me, is to first do what I have always done which is to grind the profile at 90 degrees and grind the bevel to nearly the edge and hone from that point on.

I look at the issue this way. A honing jig is just that--it is a holder to aid in fixing the bevel angle and desired shape. This is the same with the cambered roller on the LV MK.II honing jig, the Eclipse and its clones, the MF honing jig, the Stanley et al. All of them can produce/hone the desired camber (or straight) edge--and all of them require the user to be smarter than the jiggy. Some of them produce a more consistent result easier (less user thinking and acting). But they all require user intervention.

Derek's jiggy works the same way. It isn't automatic and foolproof. But hey, why not design, build and produce one? Or instead, you could simply tell people why one or another won't/can't work.

Take care, Mike
who recognizes you recognize Derek's works for him.


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## Paul Kierstead

Can we summarize by saying it isn't foolproof, but it sure helps?

As we say in my business; nothing is foolproof because fools are so ingenious.


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## Derek Cohen (Perth Oz)

Thanks Mike ..... =D> 

Regards from Perth

Derek


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## BrentB

Well, as one who has read a lot of results that worked in practise - that is, some one claimed to be able to do something - but were not reproducible, I have to take BugBear's side in this. In fact, in Mike's own (and several other people's, including mine) recommended solution, he explains exactly what is missing from Derek's approach.

When using the rod type tool rest, with no fixed angle guide, there is nothing to ensure correct angle. Chris adds that his jig had an angle plate. With an angle plate it will work for anyone, without an angle plate others trying this could easily foul up.

The alternative is a scribed arc on the back of the blade which gives the user a goal - grind to the scribe then stop (leaving the scribe just to be sure).

However, grinding the full bevel and attempting to reach the scribe both in the same operation can lead to overheating the edge - again, a problem with Derek's approach. Again, something Mike recommends against. First shape the iron, second grind the bevel.

In the grind the bevel part, if you don't have an angled plate, then a guide like Derek uses makes sense.

So, it works. It could work better with a couple of changes. Even with the changes it would not be my first choice.

Sharpening radiused blades


----------



## Derek Cohen (Perth Oz)

> However, grinding the full bevel and attempting to reach the scribe both in the same operation can lead to overheating the edge - again, a problem with Derek's approach. Again, something Mike recommends against. First shape the iron, second grind the bevel.



Just for reference, let me remind you that I used a 40 grit belt. With a lightish touch, the belt will remove metal quite fast and without heating up too much. The beveled and cambered jack blade began life with a straight 50 degree primary bevel. A LOT of steel was removed in creating the final shape. I quenched as I worked to be safe. It did not overheat. 

The belt sander is a great tool to remove a lot of metal. Nevertheless, I have done the same task (actually it was to create a scrub plane profile) with the same jig on a bench grinder - just running the curved template against the edge of the grinder rest.

Regards from Perth

Derek


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## MikeW

I think there are to separate arguments going back and forth.

One is establishing the camber. BB argues (it seems) that Derek's jiggy cannot do this as is and create the same camber on the iron as that of the jiggy. It does.

The second is producing the bevel proper. Derek is doing both at once.

I think that doing both at once is prone to the problem that Brent is pointing out, that is overheating the iron. That is an issue, but it is a procedural or best practices issue.

Creating camber on an iron that matches the jiggy is separate...or at least I separate them..issue.

As mentioned, there are procedural means to obviate overheating (do the operations separate) and or consistency in the bevel angle. The latter is easily done via experience, an angled rest in conjunction with the jiggy, a combination or [insert method here]. The former also has solutions. Water-based wheels (too slow), a light touch and coarse grits (mine and Derek's prefered means), or as mentioned, doing the grinding of the camber and shaping the bevel separately. However, doing them separately also introduces the possibility of overheating too.

This is where a modicum of understanding how fast heat is generated on the various mediums and especially what one person is using or has to use. It is also good practice to never grind to the very edge on bench grinders or belt sanders--unless with experience one knows how to keep the heat from tempering on their equipment (as much art as anything) and is using dressed coarse belts/wheels. Hand-cranked and water-based systems are also viable means but slow (and one can still overheat an iron with a hand-cranked system).

So what's the point to all my rambling? None, really. The important thing is to simply get the iron(s) into the shape desired, sharp, and make something.

Take care, Mike


----------



## DaveL

Hi Brent,

Welcome to the forum.

Your link has been caught by our spam trap, it will stop happening once you have a few more posts to your name.



BrentB":399s681y said:


> Sharpening radiused blades


----------



## bugbear

MikeW":17f84mnx said:


> I too fear the point is lost, BB.
> 
> The single-point requires more user intervention and changes the bevel angle as it moves to the outer edges. Which makes sense as that is how one produces a fingernail grind on a turning gouge. Derek's jiggy produces an even bevel angle.
> 
> The single-point changes the distance from the pivot-point to the edge. The other jiggy does not.
> 
> However, there is nothing in Derek's jiggy (or the other) to prevent one from over grinding and thus changing the desired camber. That part is user experience.



Yes - points I understood but didn't state; I should have. for clarity and explicitness.

Interestingly, _*if*_ one could somehow keep the assembly in the second diagram horizontal, possibly with a back rest, the jig does indeed become fully generative. Derek's jig "fails" only if the bevel angle is allowed to grind away without limit.

Your point about even bevels is well put.

There may be a discussion to be had about what template radius generates what blade radius, since the two curves are coaxial, not parallel., but I suspect this discussion would be too academic to be of interest to most.

BugBear


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## Derek Cohen (Perth Oz)

> Derek's jig "fails" only if the bevel angle is allowed to grind away without limit.



BB

The simple solution/precaution is to first mark the camber outline on the back of the bevel-to-be (using the edge of the jig), then set the jig, and grind to this mark only. Do not go over it (or otherwise you need to reset the jig again).

Regards from Perth

Derek


----------



## bugbear

Derek Cohen (Perth said:


> Derek's jig "fails" only if the bevel angle is allowed to grind away without limit.
> 
> 
> 
> 
> BB
> 
> The simple solution/precaution is to first mark the camber outline on the back of the bevel-to-be (using the edge of the jig), then set the jig, and grind to this mark only. Do not go over it (or otherwise you need to reset the jig again).
> 
> Regards from Perth
> 
> Derek
Click to expand...


Absolutely understood; that procedure will definitely result in the blade we (all?!) want.

BugBear


----------



## ivan

Provided you roll the template steadily from side to side, ensuring that all parts of the template's curve touch the tool rest, and don't linger too long in any one place, the camber will match that of the template about as well as a jig ground straight blade will match a square.

Don't forget a straight jig is grinding a camber of infinite radius....


----------



## BrentB

Ivan was a little ambiguous when he said


> the camber will match that of the template about as well as a jig ground straight blade will match a square


.

When the abrasive is wider than the blade, the edge can be very straight. With Derek's wide abrasive belt, he can put straight edges on very wide blades.

However, when the abrasive is narrower than the edge, there are problems. Notice that working a rounded edge with a flat abrasive always falls into this category. I used to grind with a 1" belt. I noticed that I could not get a really good ground edge no matter how careful I was to work steadily and carefully. That is one of the reasons I switched to a wide bench stone.

Forgetting the jig and getting back to the original post, we can split the problem into two parts -- preparing the iron, using the iron.

What can we say about preparing the iron? Until the iron goes into the plane, there is really nothing in its preparation that is affected by whether it is used bevel down or bevel up. If we can camber a bevel down iron, we can camber a bevel up iron.

It has been observed, correctly I think we can agree, that blades bedded at 12 degrees require about 3.4 times the curvature of blades bedded at 45 degrees. So, it comes to a question of degree. Can we sharpen to a smaller curvature. This is really only a problem for the extreme curvature of an iron used for scrubbing. In my experience, with radii from 6" to 3" there is not a lot more difficulty. Find a stance that lets you work through the full range of motion, practise a couple of times with the blade just off the abrasive, use light passes, ... Grinding is not much of an issue. Honing might be, but if you can hone a bevel down scrub iron you should be able to do a more extreme curve.

That leaves us with the problems during use. With 3.4 times the curvature for an equivalent use: Is there more effort? Is there faster edge wear? Is there a surface quality effect?

On surface quality, I suspect that most of the experience with surface quality and cambered blades comes from using hollows and moulding planes. There the geometry of the corners of the blade make it a scraper rather than a plane, resulting is degraded surfaces. These are final use planes - unless you sand after them. The scrub is not a final use plane, so surface quality cannot be an issue. On the much smaller radii of the jack and try planes, I would not expect it to be a problem (it is not on the corresponding moulding planes).

So, we are left with effort and edge durability as issues.

Anyone ready to try to compare the two? I might try to set up a bit of a test in the next couple of weeks. Can't be the same blade in the same plane, but something might be possible.

Brent

[Who really did not want to drag this thread out but noticed the "about as well" in Ivan's post, which is ambiguous, probably intentionally, so had to give the can one more kick and then got a little long winded.]

[Who hopes the connection stays up during submit of this second attempt. This first attempt had some comments about preparation which I hoped would not restart the discussion, but I cannot remember them now. I don't think further discussion of the grinding jig is necessary - it works.]


----------



## Derek Cohen (Perth Oz)

Hi Brent

Thanks for adding those points, especially the bit about "If we can camber a bevel down iron, we can camber a bevel up iron".

In summing up, I must explain a little more where the motivation for the original article came from...

When it comes to handplanes, I am torn between using BU and BD types. I enjoy the woodies I have, mostly HNT Gordon and Mugingfang, all bevel down planes. To prepare these, I grind a hollow bevel on a high speed grinder and then freehand them on waterstones. Nothing special. You will find this surprising perhaps, but I hate sharpening! One of the reasons I do research on it is because I am trying to find an economical method. KISS rules. I strop on leather as I work to maintain the edge. These BD planes work for me as I like their balance and the Gordon planes have the performance needed to work Australian timber. 

There are a couple of reasons why I make the effort to get on top of BU planes. Firstly, these are exceptionally comfortable and balanced planes. This makes it easy to use them well. Secondly, they are capable of being tuned to work at very high angles of attack, which is essential for most of our hardwoods. I think that a lot of hobbyists enjoy their ability to use different cutting angles. 

But ... they need to be prepared differently to BD planes. They are not the plane for someone who is not prepared to do things in a slightly obsessional way.  

I spent quite a while trying to treat the BU planes as if they were BD planes. I ground bevels on the bench grinder to 50 degrees and then tried to freehand them on waterstones. I could get sharp edges, but they were straight edges only. Eventually I had to accept that these planes needed to be treated differently. Since the secondary bevel is so important (unlike BD planes, where the frog angle is all important), these planes need to be prepared with a honing guide (the exception being the 37 degree included angle. There I hollow grind at 25 degrees and then freehand). I really am quite lazy and a honing guide is not my preferred style, but I have spend quite a bit of time working with various guides, especially the Veritas, and using one can be quick and painless. Still, I wish I didn't need to use one, and this is where the ambivalence lies. This thread was about coming to terms with this issue and accepting what needs to be done to use BU planes with camber. 

Happliy, only a jack requires a radical camber. A smoother and jointer can be done as easily as a BD plane.... just as long as you prepare the primary bevel at 25 degrees. The subsequent cambered microbevel needs to remove significantly less metal than cambering a full face high angle bevel. Thus the door to cambered BU blades is opened, and one of the main criticisms levelled at BU planes is now a thing of the past.

So the BU planes are technical to prepare, and this will contiinue to polarise users. Some will rail against this and see it as unnecessary fussiness. Others will just accept it as the entry fee to use a style of plane that is rewarding in use and performance. 

I like both types of planes - there will always be pros and cons with each. It should not be about one or the other. One man's meat ....

Enjoy the rugby.

Regards from Perth

Derek


----------



## ivan

Just another way of saying both work OK and neither constitutes an absolute of precision!


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## David C

Derek,

"Not liking sharpening" is a bit of a snag.

Being comfortable with sharpening is one of the most important things in woodworking.

Standard bench planes are actually easier to set up for difficult timbers.
A very narrow 15, 20 or 25 degree back bevel is easy and quick with an Eclipse type guide.

Eclipse type is acually much simpler, easier and less cumbersome to use than the Veritas, once you get used to it. Veritas will do skewed blades, but so will many others.

Adjusting of Squareness on chisels and plane blades, straight edges, cambered edges of varying profile (except scrub) are all straightforward, and the ruler trick massively increases the probability of a really sharp edge by correctly honing away the wire edge.

In the time it takes to remove a plane blade and strop it one might as well have sharpened it.

I don't know how much you travel but a few days would give me the opportunity to get you to love sharpening.......? It really is not that difficult.

Think how much more time there would then be for making!

best wishes,
David


----------



## bugbear

David C":2fdz172y said:


> In the time it takes to remove a plane blade and strop it one might as well have sharpened it.



Plane blades are an interesting special (but common) case.

There is considerable overhead in removing a blade from a plane, removing the cap-iron (if present), replacing the cap-iron (ditto), replacing into the plane, and readjusting the plane.

This high overhead can justify quite elaborate sharpening procedures.

The counter-example is a chisel, where sharpening overhead can be quite intrusive.

BugBear (jig fan, who occasionally hand touches up chisels)


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## David C

BB,

I don't think 2 to 4 minutes using £5 guide and two waterstones counts as elaborate.

Although I do acknowledge that 1 to 2 minutes might be the target for freehand oilstone users.

David


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## Derek Cohen (Perth Oz)

I spent a little time over the past week playing around with profiles for the LA Jack. The radical camber I posted here originally produced a typical Jack shaving of 1/32" thick and approximately 1 1/4 - 1 1/2" wide. However I was not satisfied with the profile and thought that it could be improved. 

The original profile had a radius of 5 1/2". I finally settled on a radius of 8 1/2". This is the difference on the template:







Here is the profile in the mouth of the LA Jack:






The shavings are wider now, about 2":






.. and with a miniscule loss of thickness (still efectively 1/32" thick).






I think that I will keep this one.

Regards from Perth

Derek


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## bugbear

David C":17jezvsm said:


> BB,
> 
> I don't think 2 to 4 minutes using £5 guide and two waterstones counts as elaborate.



I suspect "elaborate" is a humpty dumpty word, meaning what the speaker means...

BugBear


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## bugbear

Derek Cohen (Perth said:


> I spent a little time over the past week playing around with profiles for the LA Jack. The radical camber I posted here originally produced a typical Jack shaving of 1/32" thick and approximately 1 1/4 - 1 1/2" wide. However I was not satisfied with the profile and thought that it could be improved.
> 
> The original profile had a radius of 5 1/2". I finally settled on a radius of 8 1/2". This is the difference on the template:



Did you mark the new camber on the blade prior to the regrind? :twisted: 

BugBear


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## Derek Cohen (Perth Oz)

BB

Did I mark the camber beforehand? Did I ...?

Yes I did :lol: 

Life would not be worth living around here if I had not! :roll: 

Regards from Perth

Derek


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## bugbear

Derek Cohen (Perth said:


> BB
> 
> Did I mark the camber beforehand? Did I ...?
> 
> Yes I did :lol:
> 
> Life would not be worth living around here if I had not! :roll:
> 
> Regards from Perth
> 
> Derek



It might have made an interesting experiment to mark the NEW camber on the blade, and attempt to regrind with the OLD template...

I suspect it would have worked just dandy, but now we'll never know 

BugBear


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## David C

Alice in Wonderland and of course The Hunting of the Snark.....

I wonder who remembers and liked White Rabbit?

David


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