Plane Blade Camber

[tnimble]

Actually "concave" and "convex" are independent of orientation. (But it's still nice to have those pictures.)

Why can't plane #2 make a fine shaving, as long as you keep the toe down on the work and don't let it tip back when you get to the hollow?
Throughout the whole shaving the mouth floats above the surface. Relative to the mouth the blade has to be set outward to be able to hit any wood. Instead of slicing off a thin piece of wood you are pulling out fibres. There fore the blade has to be set even more outward making only thick shavings and hogging possible.

Does rubbing a plane on sandpaper on a flat surface plane #5 rather than plane #4? You would get a long flat region in the center?

Depends on technique. The plane will be like #5 but will turn into #4 when one continues to flatten with sandpaper on a perfect flat surface.

Springs? What springs? The only spring I know of vis a vis Japanese planes involves the blade and its relationship to the bedding.

I do mean bamboo or brass leaf springs in front and or behind the blade. The springs push down the wood fibres with more force than a perfectly flat sole can. This extra downward pressure makes an cleaner shavings especially on ultra thin stock needed for for instance kumiko for which wood has to be planed down to a thickness that can be as thin 3mm.

As a curiosity, if he knew the ultimate customer, and the customer consider himself (or was considered to be) a craftsman, would the plane be flattened or not? It seems that it might be an insult to assume the craftsman would not be flattening the plane to his own satisfaction, OTOH sending an "incomplete" plane could be considered poor form. Japanese etiquette can be complex...

The plane would be flattened, sized and shaped specifically for the intended wortk, the wood species to be planed and the craftman who requested the plane.

 

[pam niedermayer]

I don't think that effects Jeff's right to withdraw them.

Certainly doesn't, never claimed he had no right to withdraw them.

As to the rest of your reply, I'm not sure I violated any copyrights at all. I attributed the text to Jeff Gorman. It was in the service of education, albeit not formal. The pages were once displayed/published. I think what I did was what we in the US call fair use. It's not as if I published a site and included all Jeff's pages as my own.

Pam

 

[adrian]

Why can't plane #2 make a fine shaving, as long as you keep the toe down on the work and don't let it tip back when you get to the hollow?

Throughout the whole shaving the mouth floats above the surface. Relative to the mouth the blade has to be set outward to be able to hit any wood. Instead of slicing off a thin piece of wood you are pulling out fibres. There fore the blade has to be set even more outward making only thick shavings and hogging possible.

I don't understand. I mean, obviously not having the support in front of the blade is bad, as you have less defence against tear-out. But say you're planing well-behaved straight grained wood in the direction of the grain. In that case, this shouldn't matter much. Wouldn't you be able to set the blade to project a tiny bit below the hollow and take a fine shaving even though you have no support in front of the mouth?

Or are you saying that without the mouth to hold the wood down in front of the blade, the blade just pushes the wood up out of the way and kind of drags along the surface without cutting it? (Scrapers take fine shavings without any mouth so I'm not sure about this.)

I think Jeff took those pages down due to issues of copyright. You might respect his decision in that regard.

Does that mean the material is published somewhere?

 

[pam niedermayer]

Springs? What springs? The only spring I know of vis a vis Japanese planes involves the blade and its relationship to the bedding.

I do mean bamboo or brass leaf springs in front and or behind the blade. The springs push down the wood fibres with more force than a perfectly flat sole can. This extra downward pressure makes an cleaner shavings especially on ultra thin stock needed for for instance kumiko for which wood has to be planed down to a thickness that can be as thin 3mm.

Have you ever used a Japanese plane? Made a lot of shoji? Or merely watched St. Roy's show with John Reed Fox (http://stream1.unctv.org/ramgen/webdev/wws/2600/wws_2608_3.rm?usehostname)? This is such a specialized plane that it wouldn't be what most people mention in a general conversation about Japanese planes. It would be mentioned by people who make a lot of shoji. Or, to reiterate, bamboo springs wouldn't be of concern for tuning/reconditioning planes.

Pam

 

[bugbear]

I don't think that effects Jeff's right to withdraw them.

Certainly doesn't, never claimed he had no right to withdraw them.

As to the rest of your reply, I'm not sure I violated any copyrights at all. I attributed the text to Jeff Gorman. It was in the service of education, albeit not formal. The pages were once displayed/published. I think what I did was what we in the US call fair use. It's not as if I published a site and included all Jeff's pages as my own.

Pam

As long as you feel OK about doing something that someone you apparently respect doesn't want you to do, that's fine then...

BugBear

 

[Paul Kierstead]

As long as you feel OK about doing something that someone you apparently respect doesn't want you to do, that's fine then...

To be fair, it isn't clear that Jeff doesn't want us to reproduce any of it. The only thing that is entirely clear is that he no longer does reproduce any of it (whether by choice or force is not clear). I really wish he would put a note on the website to clear up just this sort of thing.

 

[bugbear]

As long as you feel OK about doing something that someone you apparently respect doesn't want you to do, that's fine then...

To be fair, it isn't clear that Jeff doesn't want us to reproduce any of it. The only thing that is entirely clear is that he no longer does reproduce any of it (whether by choice or force is not clear).

It's a very thorough job; the site has also been purged from the wayback machine, which does not happen by accident.

I really wish he would put a note on the website to clear up just this sort of thing.

Agreed. I suspect it's to do with the magazine he used to work for changing hands. Much of "his" website was actually articles he'd written for magazines, and I suspect the copyright is/was assigned to the magazine, and his website existed at their discretion.

BugBear

 

[Wiley Horne]

Hi All,

Those convex/concave diagrams are just great. An excellent contribution! Further to Adrian's questions about why plane No. 2 won't take fine shavings.......In my experience, the concave plane 2 is frequently found in the wild when you acquire an unknown plane, especially a metal plane like a Stanley. It leads to erratic cutting and heavy tearout. Here's what happens, if the user is unsuspecting: he/she will tend to increase the blade depth until there is contact with the wood--at this point the blade is cantilevered beyond the sole more than it would be if there were positive support ahead of the blade. At some point in taking the shaving, the blade will catch in the wood and deflect backward and downward more deeply into the wood, then spring back bringing with it a large patch of tearout (the tearout runs ahead since the shaving is not held down). Then the blade will lose contact until another high place is encountered, at which time you get a repeat of the blade digging in deeply, springing back, and causing tearout.

In regard to dais, and how they are found when bought new at retail....Based on several Funahiros and Mosakus and Gomi's I have received new, in each case, the dai was relieved by just a few thousandths between front of mouth and leading edge, and similarly by a few thousandths behind the mouth, so the tail is slightly in the air and the blade is the last thing that touches the work. Most of these were Inomoto dais, but the Funahiros were by another daiya, whose mark I didn't know. Maybe this is typical of US deliveries only. I have also bought a cheap plane, and it's dai was just a mess. But the more expensive planes came with a few thousandths of relief in the dai. As delivered, this relief will leave about a 1/4" wide flat in front of the mouth: Some users will scrape this flat down to a very narrow line of contact, 1mm or less, in order to get more psi of pressure on the shaving, just ahead of the blade.

Wiley

 

[pam niedermayer]

...
To be fair, it isn't clear that Jeff doesn't want us to reproduce any of it. The only thing that is entirely clear is that he no longer does reproduce any of it (whether by choice or force is not clear). I really wish he would put a note on the website to clear up just this sort of thing.

Thanks, that's about all I've been able to determine, too. Without clear direction, it's difficult to know what's what. And I find it hard to believe that Jeff Gorman wants to be forgotten and/or no longer wishes to help other woodworkers.

Has he written a book?

Pam

 

[tnimble]

Have you ever used a Japanese plane?

I do not own any Japanese planes myself. In fact I am only just starting to master jointing and thicknessing boards with hand planes. Way back, 20 years or so when I was teached into wood and metalworking I was told hand tools are slow and inaccurate and should not be used. "Look at any old house, they build them with hand tools, everything is off level and crooked". And why would one investigate in good technique if when gluing up a table top, one can joint the edges of a few boards, glue them up in the hydraulic press and then run the entire table top through the 40" thicknesser. Why would we want to taper the legs by hand when we simply can recall the taper program on the CNC mill?

I now do own a lot of handtools and starting master most of them very well. I've no access any more to the machines I used to rely on and quickly learned that with 'hobby' power tools things aren't that easy and you miss out on much.

Currently I stick to to hat I'm familiar with myself: Stanley planes. I have done quite a few restorations backed with the knowledge of metalworking and engineering and instruction what one want to be done to a plane . Now I also know how to use them myself.

Made a lot of shoji?

shoji are room divers / screens, right?

Or merely watched St. Roy's show with John Reed Fox (http://stream1.unctv.org/ramgen/webdev/wws/2600/wws_2608_3.rm?usehostname)?

Love that show (thanks for mentioning the show, I just found out they've put another season online! ). I very much enjoyed the episodes on the barley twist table and the historic machines. Just watched the episode with John Reed Fox again and indeed he has a very special plane made for him that features a spring to push down the toothpicks he planes with it. This plane also has a special guidance thingy and sled very impressive tool. Besides John Reed Fox his plane I've seen other and more simple planes having springs embeded in the sole. Planes without all the guide things and the sled.

This is such a specialized plane that it wouldn't be what most people mention in a general conversation about Japanese planes.

Iv'e neven said all japanese plane have springs. I've only said some do have one in front and or behind the blade. For such a plane the various concavities in the planes sole wouk'd not help flattening such a plane.

It would be mentioned by people who make a lot of shoji.

Based on that shoji are roomdiveders / screens a plane such as John Reed Fox uses (or one that's much simpler) is used for a lot more things. John Reed Fox site lists a lot more tpyes of furnature. One of my best friends is a scholar in the field of historic art and science and who just returned from Turkey setting up a new museum. The tings shown by John Reed Fox are not specific to Japanese shoji. Most arabic cultures have very similar techniques and decorations like John Reed Fox uses.

Or, to reiterate, bamboo springs wouldn't be of concern for tuning/reconditioning planes.

The bamboo will be thinned reducing the spring force. Also a spring in from of the blade would most probably make the gap between the blade and the spring wider. Having the same effect when widening the mouth of plane.

Hi All,

Those convex/concave diagrams are just great. An excellent contribution! Further to Adrian's questions about why plane No. 2 won't take fine shavings.......In my experience, the concave plane 2 is frequently found in the wild when you acquire an unknown plane, especially a metal plane like a Stanley. It leads to erratic cutting and heavy tearout. Here's what happens, if the user is unsuspecting: he/she will tend to increase the blade depth until there is contact with the wood--at this point the blade is cantilevered beyond the sole more than it would be if there were positive support ahead of the blade. At some point in taking the shaving, the blade will catch in the wood and deflect backward and downward more deeply into the wood, then spring back bringing with it a large patch of tearout (the tearout runs ahead since the shaving is not held down). Then the blade will lose contact until another high place is encountered, at which time you get a repeat of the blade digging in deeply, springing back, and causing tearout.

Well said. As for why a scraper won't produce the tearout while having no mouth at all. A scaper's hook is pulled across the surface. A plane blade is pushed through the top layer of the surface.

In regard to dais... As delivered, this relief will leave about a 1/4" wide flat in front of the mouth: Some users will scrape this flat down to a very narrow line of contact, 1mm or less, in order to get more psi of pressure on the shaving, just ahead of the blade.

From what I've understood the planes with a spring (either brass or bamboo) in front of the blade is meant to do that exact same thing.

 

[Paul Kierstead]

Well said. As for why a scraper won't produce the tearout while having no mouth at all. A scaper's hook is pulled across the surface. A plane blade is pushed through the top layer of the surface.

If I may suggest, you should read up on type 1 vrs type 2 shavings and some of the work that has been done regarding different methods of shaving off wood.

 

[adrian]

Well said. As for why a scraper won't produce the tearout while having no mouth at all. A scaper's hook is pulled across the surface. A plane blade is pushed through the top layer of the surface.

My remark wasn't about why a scraper doesn't produce tear out but rather why it cuts at all if the presence of a mouth is required to enable the plane to cut a fine shaving. This would actually suggest that I could have the plane taking a fine shaving and then if I opened the mouth up it would quit cutting. Does this occur?

My plane with a hollow doesn't produce tear out. I've planed figured wood with it with no tear out. It doesn't cut and then not cut and then cut again if I try to take a shaving. At least, not so I've noticed. It just ceasing cutting entirely if I get much below 0.002". (I had previously figured it was a problem with making such a fine adjustment.) I believe that my plane looks like plane #1 on the list, with a broad hollow about 0.0015" deep.

But it still seems like plane #2 should be able to take a small shaving if the blade is extended far enough and the flat regions are kept flat to the work. I'm not talking here about tear out or finish quality but simply whether a shaving is produced or not.

 

[ivan]

If the plane's sole is convave by 2 thou it can't cut a 2 thou shaving - the blade will miss the stuff. It will only cut at the beginning and end of the timber, making it, the wood, convex. I bought a Record no. 6 40+ yrs ago that turned out to be 25 thou concave. I didn't know about such things then and it caused me much grief! (naive enough to assume a brand new plane would be flat)

A bevel down plane blade with very close set ("sharpened") cap iron virtually duplicates the cutting geometry of a scraper. The added advantage of a very fine set mouth means that the plane can probably cut well at somewhat kinder angles and thus produce a better surface direct from the blade.

Here'sa good place to start reading.

 

[adrian]

If the plane has a local concavity around the mouth but the rest of the sole is flat (that's plane #2 in the pictures) then it seems to me that you could just extend the blade beyond the depth of the concavity and it should still cut. So if it is 2 thou concave then if you extend the blade 3 thou it should cut a 1 thou shaving.

It seems like the same thing ought to be true of plane #1 as long as you cut only in the middle of the wood. The problem is that when the sole is entirely concave along it's length, when you start the cut and when you finish it then your cut will deepen to the total length of the blade projection. Is that right? This would mean that plane #1 would have a strong tendency towards making things convex because it would take thicker shavings at the ends, which would explain why my slightly concave surface turned convex when I took one set of shavings.

A bevel down plane blade with very close set ("sharpened") cap iron virtually duplicates the cutting geometry of a scraper. The added advantage of a very fine set mouth means that the plane can probably cut well at somewhat kinder angles and thus produce a better surface direct from the blade.

I don't think "virtually" counts for anything in this case. A scraper produces a type II shaving by causing the chip to break right at the cutting point. Things that are farther back, even just a tiny bit, can't change this. The cap iron is too far back from the edge (even if it's only 1/64") to change the type of shaving.

 

[pam niedermayer]

If the plane has a local concavity around the mouth but the rest of the sole is flat (that's plane #2 in the pictures) then it seems to me that you could just extend the blade beyond the depth of the concavity and it should still cut. So if it is 2 thou concave then if you extend the blade 3 thou it should cut a 1 thou shaving....

That assumes that the blade is capable of doing more than gouging at such an extension.

Pam

 

[ivan]

Adrian, if you follow the links you will see (along with associated photographs) that the cap iron is set somewhat closer than 1/64", namely about 4 thou. I suspect this is actually smaller than the burr raised on many scrapers. Further, it appears from the reported research that a cap iron set to 12 thou (less than 1/64") is having no effect on tearout in difficult grain.

 

[adrian]

Adrian, if you follow the links you will see (along with associated photographs) that the cap iron is set somewhat closer than 1/64", namely about 4 thou. I suspect this is actually smaller than the burr raised on many scrapers. Further, it appears from the reported research that a cap iron set to 12 thou (less than 1/64") is having no effect on tearout in difficult grain.

Which links was I supposed to follow? I don't see any.

I was arguing that the cap iron should not affect performance on difficult grain, and that it does not turn the plane into a scraper. It appears that you are agreeing with my when you say that a cap iron set to 12 thou has no effect on tearout. When it comes down to it, I don't know the size of the interface at which the type II shaving breaks, so I don't know how close the chip breaker would have to be to affect this process. (I don't think the size of the scraper burr has anything to do with it.) From a theoretical standpoint, if you put the chip breaker right at the edge then it would change the cutting process, but it doesn't seem like this could happen in a real plane.

If I camber my blade the recommended 0.25 mm that is 10 thou, so my cap iron position is already forced to be at least 10 thou back from the crown of the blade, and presumably a few thou more, at least, since it won't come right up to the blade at the edges.


I remeasured my plane sole and got results not exactly consistent with the previous ones. If I shine a light behind my straight edge then I see light almost everywhere. But I tried inserting my feeler gauge and this time, found that most places the 0.001" gauge would not fit under the straight edge. There was one spot where it would fit in front of the mouth, and the .0015" gauge fit in behind the mouth, but over most of the rest of the plane it wouldn't fit. (This is in contrast to my previous measurement which found the .0015" gauge fitting at various spots on both sides of the mouth.) I'm not sure what would make the difference. A different part of my straight edge (which is only certified to .001")? Different clamping forces the way the plane tool was held in the vise?

 

[Jeff Gorman]

Just a thought when thinking about planes at very fine settings; perhaps it is best not to assume that the sole is rigid - cast iron planes, eg Record 05s can deflect a few thou in use.

Some erratic performance can also be due to slight variation in pressure, hence deflection during the progress of the stroke.

Working with an extremely fine set, I've noticed that even an 04 smoother with a dead flat sole will cut when pressure is transferred from the front knob and the hand moves over the blade/frog assenbly.

 

[ivan]

Adrian, scroll up the page to my first post and look for the last sentence:

Here's a good place to start reading.

Click on the word "Here's" which is the link. Lots of relevant info there.

 

[Joe]

If I could just backtrack a little...

I read David Charlesworth's article in F&C as suggested and I really like the look of the Odate crowning plates. I hope someone starts importing these soon.

One thing that occurred to me - wouldn't the most cost effective thing be to buy the convex plate and then make "two-sided" waterstones (i.e. one flat side and one concave side)? Then you'd only need one set of stones (plus the dressing plate). The only slight flaw is that my polishing stone is glued to a wooden base, but I don't suppose they're all like that.

Anyhow, I have finally succeeded in putting a slight camber on my favourite plane iron. It's amazing how a barely perceptible curve on a piece of metal can make me so happy.