David charlesworth, cambered blade with a back bevel?

[ali27]

Guys, I have enjoyed DC's video ''Furniture-Making Techniques'' a lot. There is one thing
I don't understand.

For really though wood, DC sharpens his plane blade with a 25 degree back bevel. This part I understand. DC
uses a slight camber on his blades, using pressure at the sides to create it. So far easy to understand.

Then DC removes the wire edge(hones the back bevel), but uses only centre pressure. That seems odd to me.
The middle of the blade(both on the beveled and the flat/back side) is touching the waterstones first. So
by using only centre pressure, more of the middle is removed than on the sides, since the middle is
touching first and only by abrading the middle can one start honing the sides. I think DC is changing
the geometry of the blade this way. What do you guys think?

When there is no back bevel, the flat face is touching the stone evenly and there is no problem, but with
a back bevel the middle of the edge is touching the stone first and the edges last. This issue might not be
a problem with a tiny back bevel that is removed with the ruler trick. However the steeper the angle of the
backbevel, the more it becomes a problem(if my thinking is correct).

Have I got it wrong?

Ali

 

[Corneel]

DC has converted to using the chipbreaker instead of backbevels to tame tearout prone woods. So your info is old . Backbevels are a royal pain anyway.

 

[Karl]

DC has converted to using the chipbreaker instead of backbevels to tame tearout prone woods. So your info is old . Backbevels are a royal pain anyway.

That's interesting - any further info?

I always found back bevels to be very useful way of dealing with tearout. It did necessitate keeping a spare blade though.

Cheers

Karl

 

[David C]

Ali,

I usually keep a very slight camber on the bevel side, but a straight bevel on the back bevel side. That is why centre pressure works for the back bevel side.

Does this answer your dilemma?

Corneel,

I have not converted exclusively to the C/B method. I now explain and demonstrate both methods to my students.

Struggling to understand why you would think back bevels are a pain? I found them very useful over a number of years, as do many luthiers.

best wishes,
David Charlesworth

 

[woodbrains]

DC has converted to using the chipbreaker instead of backbevels to tame tearout prone woods. So your info is old . Backbevels are a royal pain anyway.

That's interesting - any further info?

I always found back bevels to be very useful way of dealing with tearout. It did necessitate keeping a spare blade though.

Cheers

Karl

Hello,

Used smothers are so cheap to buy, a whole dedicated plane is the best course. I got a very nice, early Record 4 1/2 for £10, one's that needs a bit of a clean up, can be had for less. Simple solution and any (ill) perceived trouble with back bevels disappear, opening up a whole world of plane versatility.

Mike.

 

[Trafalgar]

Not sure that back bevels are really necessary when taming tough boards:

http://www.popularwoodworking.com/woodw ... ipbreakers

The plane with a high-angle frog and bevel down configuration along with a closely set and honed chipbreaker was the "winner."

A plain bevel down smoother (frog bedded at 45*) was able to plane, tearout-free, all but the last test board which was pulled out of the trash bin.

 

[Corneel]

Corneel,

I have not converted exclusively to the C/B method. I now explain and demonstrate both methods to my students.

Struggling to understand why you would think back bevels are a pain? I found them very useful over a number of years, as do many luthiers.

best wishes,
David Charlesworth

For me personally, maintaning the backbevel is just too much bother. It's not easy to do freehand, hard to get that exact 15 degrees. So I'd have to use a jig, but that means "endless" going back and forth. Set the jig for the bevel first, sharpen and hone the bevel. Then set it again, now for the backbevel. Hone that one. I always like to go back and forth a few times between the back and the bevel with ever less pressure. that becomes intollerable when you need to reset the blade in the jig each time. Then after a while I might not want the backbevel anymore on that particular blade, so that means an extended grinding session.

When I get some really irksome wood, I have an old German reform smoother with 49 degree bedding angle and a double iron. It's hard to find a piece of wood that can't be planed with that one.

 

[David C]

Back bevels are a readily available way of simulating high angle frogs and, high angle planes.

Brian Burns excellent pamphlet on this subject used to be available from the Japan Woodworker. I hope it still is.

Back bevels on machine planer blades are also an old and effective way of dealing with interlocked grain, tropical timbers.

best wishes,
David

 

[ali27]

Ali,

I usually keep a very slight camber on the bevel side, but a straight bevel on the back bevel side. That is why centre pressure works for the back bevel side.

Does this answer your dilemma?

.........

best wishes,
David Charlesworth

I understand what you are saying David. Do you agree that when you put a camber(no matter how slight it is) on the beveled side and then sharpenthe back bevel only using centre pressure, you are removing more material from the middle of the blade as that part is touching the stone first?

Would it not be more correct(to keep the camber precise and not alter the geometry) to use the same technique on the back flat face as you did on the beveled side? Obviously the back bevel is much smaller than the beveled face so far less strokes are needed. So maybe(for the flat face) 1 stroke centre pressure, one left side, one side right side and one stroke for the edges ?

Now obviously you are having very good results with the technique you are using sir, the proof is in the pudding. But I keep
wondering if there could be a slight improvement by using the camber sharpening technique on the flat back face as well.

Ali

 

[Trafalgar]

Corneel,

I have not converted exclusively to the C/B method. I now explain and demonstrate both methods to my students.

Struggling to understand why you would think back bevels are a pain? I found them very useful over a number of years, as do many luthiers.

best wishes,
David Charlesworth

For me personally, maintaning the backbevel is just too much bother. It's not easy to do freehand, hard to get that exact 15 degrees. So I'd have to use a jig, but that means "endless" going back and forth. Set the jig for the bevel first, sharpen and hone the bevel. Then set it again, now for the backbevel. Hone that one. I always like to go back and forth a few times between the back and the bevel with ever less pressure. that becomes intollerable when you need to reset the blade in the jig each time. Then after a while I might not want the backbevel anymore on that particular blade, so that means an extended grinding session.

When I get some really irksome wood, I have an old German reform smoother with 49 degree bedding angle and a double iron. It's hard to find a piece of wood that can't be planed with that one.

There seems to be little reason to monkey with the cutter, where there is more opportunity for something to go awry, when working the mild steel of the capiron gives the same effect.

Back bevels require maintenance at every honing, and no matter how 'easy,' therein lies its tediousness. Once the capiron is honed and tuned it's done, never needing to be touched again.

Otherwise, we have the 'poor' conflicted woodworker who already owns thousands of dollars worth of equipment and suddenly draws the line at owning a high-angle smoother? Laughable, from where I'm sitting.

 

[woodbrains]

Corneel,

I have not converted exclusively to the C/B method. I now explain and demonstrate both methods to my students.

Struggling to understand why you would think back bevels are a pain? I found them very useful over a number of years, as do many luthiers.

best wishes,
David Charlesworth

Otherwise, we have the 'poor' conflicted woodworker who already owns thousands of dollars worth of equipment and suddenly draws the line at owning a high-angle smoother? Laughable, from where I'm sitting.

Hello,

So the bit about a used plane for a tenner, is lost on you, then?

Cap iron settings work, so do back bevels, it is all good fun to try and learn. It is only the can't be bothered, who seem to not like the bak bevel. Some can and do and find them beneficial.

Mike.

 

[David C]

Ali,

You should try your improvements.

I keep the back bevel straight (and very narrow) to keep the number of sharpening stages down. It goes like this.

1. Get wire edge in center of blade and apply same number of strokes to rest of camber. Four more finger positions. 800 stone.
2. Turn blade over and get wire edge, (straight bevel). 1,200 stone.
3. Polish this bevel.
4 Turn over and polish camber. All polishing done on 8,000 stone.

I would be surprised if this takes much more than 4 minutes. Perhaps I will check when I have some time.

David

 

[Trafalgar]

Hello,

So the bit about a used plane for a tenner, is lost on you, then?

Cap iron settings work, so do back bevels, it is all good fun to try and learn. It is only the can't be bothered, who seem to not like the bak bevel. Some can and do and find them beneficial.

Mike.

I would simply point you back to the Schwarz article to which I linked and I think it is an important one because others were involved in the testing, it was not a lone effort with the results left to one person's (skewed?) judgment. Otherwise, I'm doubtful that economizing on the last plane to touch the wood by simulating a high angle plane, for those whose investment is already measured in the thousands of pounds, is logically consistent. And it could be moot anyway based on the Schwarz, et al. tests.

Woodworking is not a cheap hobby unfortunately. Wood has to be bought and it can't be picked up 'for a tenner,' or at least not very much of it.

Those truly on a budget, though, can be heartened by the fact that a standard 45* bedded plane with a close and tuned capiron was able to handle a variety of problematic woods:

"...then Deneb [Puchalski of Lie-Nielsen], Dave Jeske of Blue Spruce Toolworks and I [Chris Schwarz] put the planes to use on a variety of woods. We tried reverse-grain cherry. It was no challenge for any of the planes. Then curly bird’s-eye maple, planed against the grain. Again, no problem. Ancient fossilized purpleheart. Nope. No difference. Then a board that we were told was unplanable: big furry, roey mahogany.

Again, all the planes handled the wood with no real problems."


End quote.

 

[Corneel]

The beaty of the capiron is its adjustability. With just a screwdriver you can get all the tearout reduction you want and need, untill you get into scraper teritory. I can see how the backbevel is a quick solution when you first meet a difficult piece of wood and don't have a properly prepared capiron yet. But not as a permanent solution. If you want to work with high cutting angles it's much smarter to buy a high angle or bevel up plane.

 

[David C]

The fact that there are other ways of dealing with tearout, in no way diminishes the usefulness of the back bevel.

Whose skewed judgment here, has nothing whatever to do with the original question?

David Charlesworth

 

[woodbrains]

Hello,

I have been setting capirons as close as I can, for over 25 years, it did not take some Japanese engineers for me to have the epiphany, as it seems to have taken for some here. I have been playing with back bevels for over 10, long before I ever heard of Chris Schwartz, or any of the others. None of this is new territory to me. I do have a great woodworking kit, collected over decades, but I do not have thousands of pounds worth of planes, so having a dedicated smoother with a back bevel, for the princely sum of a tenner, s not something I think is anachronistic, or extravagant. If the OP wants to experiment with back bevels, then let us help him to do so.

Naysayers are a right royal pain to learning. Planes, total waste of time! There is all that sharpening and effort pushing, and you need hundreds of them all collecting dust on the shelf, and rusting. And they all cost hundreds of dollars each and take ages to learn to use. everything is made from veneered mdf anyway. Just get a random orbit sander and save thousands, stop wasting your time and get into the 21st century! See what I mean! :lol:

Mike.

 

[Corneel]

No indeed my response doesn't directly answer the question at all. I try to give Ali a wider perspective. He seems to be bent on going through all the deadends of extreme sharpening from the last few decades and trying to theorise everything without trying to listen to simple practical advise.

To answer the question about back beveling a cambered blade: just look at it and continue until you are happy.

Btw, another disadvantage of backbevels, it becomes hard to feel the wire edge, making sharpeninh harder.

 

[Trafalgar]

The beaty of the capiron is its adjustability. With just a screwdriver you can get all the tearout reduction you want and need, untill you get into scraper teritory. I can see how the backbevel is a quick solution when you first meet a difficult piece of wood and don't have a properly prepared capiron yet. But not as a permanent solution. If you want to work with high cutting angles it's much smarter to buy a high angle or bevel up plane.

Well said.

 

[Trafalgar]

Hello,

I have been setting capirons as close as I can, for over 25 years, it did not take some Japanese engineers for me to have the epiphany, as it seems to have taken for some here. I have been playing with back bevels for over 10, long before I ever heard of Chris Schwartz, or any of the others. None of this is new territory to me. I do have a great woodworking kit, collected over decades, but I do not have thousands of pounds worth of planes, so having a dedicated smoother with a back bevel, for the princely sum of a tenner, s not something I think is anachronistic, or extravagant. If the OP wants to experiment with back bevels, then let us help him to do so.

Naysayers are a right royal pain to learning. Planes, total waste of time! There is all that sharpening and effort pushing, and you need hundreds of them all collecting dust on the shelf, and rusting. And they all cost hundreds of dollars each and take ages to learn to use. everything is made from veneered mdf anyway. Just get a random orbit sander and save thousands, stop wasting your time and get into the 21st century! See what I mean! :lol:

Mike.

Sam Allen was a proponent in the 1970s of using a block plane honed at a higher angle for local tearout. And this is an old instrument maker's 'trick' anyway - going way back before the 1970s for sure. Allen even had an angle equivalency chart for low angle blocks and regular angle blocks in one of his books (from the 1980s if I'm not mistaken). For the cost of a replacement iron for a common block plane, high angle planing was and still is available for anybody who needs it.

Back beveling would be third on my list (FWIW) as a way to access high angle planing. The OP can obviously proceed with his experimentation, but he should know other options are available and are likely even more effective and this is the most important point.

Anybody regularly working highly figured or gnarly tropical woods (which implies an ongoing high cost of materials anyway) would be foolish not to simply buy a high angle bevel down plane (my choice) or a bevel-up plane of some ilk. Premium dollars are being spent on highly figured and expensive tropical wood, but there's no room in the budget for a plane that makes it all easier? Really?

We've seen from the Schwarz article that a high angle plane with a tuned and honed capiron is a potent one-two punch and handled everything he and his cohorts threw at it.

 

[David C]

Corneel,

I understand that you think chipbreaker use is superior, however the wire edges are perfectly easy to feel (if you know where to feel) and sharpening is not "harder". It just involves one extra stage.

These attempts to undermine an excellent technique, which deals beautifully with the most difficult refractory, interlocked exotics are misleading and unhelpful. I really don't understand what you are trying to achieve?

Both methods work and people will no doubt choose the one which works best for them.

David Charlesworth