Convex bevel a la P. Sellers

[Derek Cohen]

Hi Greg

With a bevel down plane (say a common angle bed of 45 degrees), the only considerations are (1) a edge between 22-37 degrees, and (2) as in the case of the latter bevel angle, at least 7 degrees clearance from the bed.

The above affords a wide variation of bevel angles, and honing does not need to be fussy. Except ... the closer to the 22 degree end, the more fragile the edge will be, and the close to the 37 degrees, the closer to the end of clearance one gets and the threat that the blade will stop cutting.

Bevel up planes are different, as you know. Going high here benefits chip control. The irony is that I have read of Paul Sellers state on a few occasions that he finds BU planes are prone to tearout and rough surfaces ... which clearly goes against the experience of thousands of happy woodworkers. The conclusion drawn from this is that he is preparing his blades for BU planes at a very low angle, and planing with angles around 37 -38 degrees (i.e. 25 degree bevel). I emphasise that this is my interpretation, but if correct one is left with either the conclusion that Paul does not understand how to set up a BU plane (which it unlikely to be the case as he is frequently complimentary of BU planes) or that he does not control his bevel angles as well as he thinks. I suspect the latter, which is influenced by comments such as this ...

"In my view the type of edge sharpness I need at the bench for a bevel-up bench plane to work effectively AND efficiently is the same for a bevel-down plane, but if a bevel-up plane is going to go wrong in the grain it often goes very wrong big time. More so than the bevel-down planes for reasons of physics. When a bevel-up plane begins to tear out the grain it can and indeed does rip the grain out at the very root mercilessly and not rarely but commonly. Unfortunately, at shows, where salesmen sell planes, they never show this plane reality even though this is the reality of why bevel-up planes differ from bevel-downs and why they never replaced the bevel-down planes through the centuries or came anywhere close to them."




The above can only occur if the bevel angle is set too low.

Keep in mind that this reply of mine is aimed at the round bevel sharpening method and not PS, from whom I have learned quite a bit - I just do not agree with all he writes.

Regards from Perth

Derek

[Jim Matthews]

Then compare all these to Seller's utilitarian furniture.

I believe 'staid' is about as nice a term as can be applied.
He kept waving the book about the cabinets he made for the Oval Office under our noses.

I practically chewed my tongue to a pulp for three days.

That said, this approach to sharpening has really worked for me.
The catch is that you need to spend the same amount of time
honing the entire bevel, lest it get progressively steep.

[James Lehr]

Thank you everyone for your input. That video that Kees linked to was very informative. Why did i not think of using my "bevel gauge" to demonstrate the bevel angle at which i wanted to sharpen my iron? Crazy simple but i'd never seen that before. I think that one of the responses is right about my angle being more like 40. I didn't gauge the angle except looking at the original 25 degree bevel and then raising the end and going to town. I went way too fast and dropped my hand too much so that I got this huge convex bevel in the middle of the face. I know b/c I placed my ruler on there and it rocked back and forth; it still does even after resharpening on my 250 grit Norton waterstone for 30 minutes in a honing guide at 30 degrees. So yes, I know that it is user error.

I guess that I am wanting to take a step forward in my woodworking to where sharpening isn't a chore that I complete every couple days or "when I get to it". I want it to be part of my woodworking and without the complexity of getting out the honing guide, getting a ruler, getting this and that and that, etc. On the other hand, I see the value in finding the system that works for me and I feel comfortable in and just do it. Confidence is so important. Thanks again everyone.

[Steve Voigt]

almost all the old tools I have seen, plane iron, chisels, plough plane irons, had a rounded convex bevel, and Paul Seller's knows how to make that work and fast.

I would be hesitant about drawing conclusions from looking at old tools. When was the tool sharpened? If you get a tool that hasn't been sharpened in 200 years, then you can be sure it was sharpened by someone who really knew what they were doing, but it is very unlikely you will find a tool in that virgin state. Much more likely is that the tool was sharpened some time in the last, say 50 years, by someone who did NOT know what they were doing. As Warren has said, the dark ages of hand tool woodworking lasted over a century.
If we look at old texts, like Moxon, Nicholson, Holtzappfel, etc., we don't see any evidence for the convex approach. We see suggestions for either hollow grinding, or a shallow primary bevel with a steeper secondary. I do recall seeing a post by Jeff Burks of a late 19th/early 20th c. text that warned against the convex approach.

I'm positive that the craftsman of old didn't have honing guides or really paid much attention to whether their plane blade was 25 or 33 or 35.666789 degrees. Those craftsman seemed to make great works of art. Just saying..

I am positive that they DID pay attention to the angles they were using, though you're right that they didn't have honing guides. Again, we can consult the historical woodworking texts and find that they were quite precise about degrees. Nicholson, for example, recommends 35° for a bench plane. English common pitch is 47.5°, so that leaves a clearance angle of 12.5°, which is within 1/2 a degree of the 12° clearance that Stanley and Veritas use on there bevel-up planes. Probably not a coincidence.

[Steve Voigt]

I believe 'staid' is about as nice a term as can be applied.
He kept waving the book about the cabinets he made for the Oval Office under our noses.

I practically chewed my tongue to a pulp for three days.

That said, this approach to sharpening has really worked for me.
The catch is that you need to spend the same amount of time
honing the entire bevel, lest it get progressively steep.

That's it exactly, Jim. If the method works for you, then go to town, two thumbs up, huzzah. There's no doubt that it works to get blades sharp. But that doesn't make the person pushing this method the second coming of whatever.

[Steve Voigt]

With a bevel down plane (say a common angle bed of 45 degrees), the only considerations are (1) a edge between 22-37 degrees, and (2) as in the case of the latter bevel angle, at least 7 degrees clearance from the bed.

The above affords a wide variation of bevel angles, and honing does not need to be fussy. Except ... the closer to the 22 degree end, the more fragile the edge will be, and the close to the 37 degrees, the closer to the end of clearance one gets and the threat that the blade will stop cutting.

Bevel up planes are different, as you know. Going high here benefits chip control. The irony is that I have read of Paul Sellers state on a few occasions that he finds BU planes are prone to tearout and rough surfaces ... which clearly goes against the experience of thousands of happy woodworkers. The conclusion drawn from this is that he is preparing his blades for BU planes at a very low angle, and planing with angles around 37 -38 degrees (i.e. 25 degree bevel). I emphasise that this is my interpretation, but if correct one is left with either the conclusion that Paul does not understand how to set up a BU plane (which it unlikely to be the case as he is frequently complimentary of BU planes) or that he does not control his bevel angles as well as he thinks. I suspect the latter, which is influenced by comments such as this ...

"In my view the type of edge sharpness I need at the bench for a bevel-up bench plane to work effectively AND efficiently is the same for a bevel-down plane, but if a bevel-up plane is going to go wrong in the grain it often goes very wrong big time. More so than the bevel-down planes for reasons of physics. When a bevel-up plane begins to tear out the grain it can and indeed does rip the grain out at the very root mercilessly and not rarely but commonly. Unfortunately, at shows, where salesmen sell planes, they never show this plane reality even though this is the reality of why bevel-up planes differ from bevel-downs and why they never replaced the bevel-down planes through the centuries or came anywhere close to them."

https://paulsellers.com/2014/04/ques...equal-to-task/


The above can only occur if the bevel angle is set too low.

Derek, thanks for a really interesting and thoughtful post. Of course you are right. It goes to show two things. First, of course Seller's method works to get blades sharp. But Second, the Achilles heel of the method is the relative imprecision with regard to geometry. One doesn't need to hit an exact degree setting to do effective work, but it's a big plus to be able to get within a couple degrees of a desired angle, rather than five or ten.

[Steve Voigt]

I guess that I am wanting to take a step forward in my woodworking to where sharpening isn't a chore that I complete every couple days or "when I get to it". I want it to be part of my woodworking and without the complexity of getting out the honing guide, getting a ruler, getting this and that and that, etc. On the other hand, I see the value in finding the system that works for me and I feel comfortable in and just do it. Confidence is so important. Thanks again everyone.

That is an extremely worthy goal, and you are right to pursue it. And if the Sellers method gets you there, that is fantastic.
If you decide that his method is not for you, some other possibilities are the hollow grind method espoused by Joel Moskowitz, and many others:
http://antiquetools.com/sharp/sharptoolsandequip.html
and the secondary-bevel method shown in this video by Larry Williams (this is how I roll):
https://www.youtube.com/watch?v=Z0ClNp_Eknw

And with that, I'm shutting up for the night.

[Roy Lindberry]

Hello all, I've been watching Paul Sellers' videos quite a bit lately and he finally had me convinced of the quickness of diamond stones on the bench and "get right back to work". That said, I bought a set of coarse, fine, and x-fine DMT stones and made up my leather strop (Just like Paul's setup on the video). I must have watched his video on sharpening plane irons at least 30 times before attempting; I just recently replaced my Stanley No. 4 iron with a Hock Iron and Chipbreaker. Previously I have used a Norton 1000/8000 waterstone with the "ruler trick" and got really great results. I don't have water in the garage so I thought having the DMT's around would make sharpening easier. Anyway, my first attempt at freehand sharpening my plane iron seemed ok (at first); i had the convex bevel and the feathered wings. I thought i had a sharp edge (felt the burr) and stopped and tried it out. I could not get a shaving to save my life. Now I'm frustrated bc I've got a plane iron that has this crazy convex bevel and I've spent about an hour now trying to re-establish the bevel at 30 degrees using my honing guide instead of freehand.

Whew that was a lot. My question is whether anyone uses Paul's freehand method and gets positive results? I think at this point I will go back to my honing guide; i'll keep the DMT stones and start using the strop and see if I can get a consistent sharp edge or if i have to go back to waterstones. Thanks.

I use his method and it works wonderfully for me.

[Jim Koepke]

If the method works for you, then go to town, two thumbs up, huzzah.

Good advice. If it works, fine.

jtk

[Pat Barry]

I would be hesitant about drawing conclusions from looking at old tools. When was the tool sharpened? If you get a tool that hasn't been sharpened in 200 years, then you can be sure it was sharpened by someone who really knew what they were doing, but it is very unlikely you will find a tool in that virgin state. Much more likely is that the tool was sharpened some time in the last, say 50 years, by someone who did NOT know what they were doing. As Warren has said, the dark ages of hand tool woodworking lasted over a century.
If we look at old texts, like Moxon, Nicholson, Holtzappfel, etc., we don't see any evidence for the convex approach. We see suggestions for either hollow grinding, or a shallow primary bevel with a steeper secondary. I do recall seeing a post by Jeff Burks of a late 19th/early 20th c. text that warned against the convex approach.



I am positive that they DID pay attention to the angles they were using, though you're right that they didn't have honing guides. Again, we can consult the historical woodworking texts and find that they were quite precise about degrees. Nicholson, for example, recommends 35° for a bench plane. English common pitch is 47.5°, so that leaves a clearance angle of 12.5°, which is within 1/2 a degree of the 12° clearance that Stanley and Veritas use on there bevel-up planes. Probably not a coincidence.

"though you're right that they didn't have honing guides. Again, we can consult the historical woodworking texts and find that they were quite precise about degrees" How in the world do you make sense of this statement. If they had no honing guides then they did it freehand and if they did it freehand they certainly were not precise about degrees.

"warned against the convex approach." For what reason would they possibly warn against a convex bevel? Its virtually impossible to get anything other than a convex bevel going freehand. No one is that precise such as to avoid some degree of convexness.

[Jim Koepke]

Originally Posted by Steve Voigt:

"though you're right that they didn't have honing guides. Again, we can consult the historical woodworking texts and find that they were quite precise about degrees"

How in the world do you make sense of this statement. If they had no honing guides then they did it freehand and if they did it freehand they certainly were not precise about degrees.

"warned against the convex approach." For what reason would they possibly warn against a convex bevel? Its virtually impossible to get anything other than a convex bevel going freehand. No one is that precise such as to avoid some degree of convexness.

They did have a guide. It is the guide supplied by a hollow grind from a wheel.

This is the beautiful part about having a hollow grind is it "self aligns" to the angle of the grind on the stone.

jtk

[Tony Zaffuto]

"though you're right that they didn't have honing guides. Again, we can consult the historical woodworking texts and find that they were quite precise about degrees" How in the world do you make sense of this statement. If they had no honing guides then they did it freehand and if they did it freehand they certainly were not precise about degrees.

"warned against the convex approach." For what reason would they possibly warn against a convex bevel? Its virtually impossible to get anything other than a convex bevel going freehand. No one is that precise such as to avoid some degree of convexness.

Take a peak at the DVD from "Tools for Working Wood", for oilstones, by Maurice Frasier, you will see how to avoid a convex bevel. The method shown, is sort of a hybrid between side to side along with advancing across all of the face of the stone. Frasisier uses a concave grind to begin with, but I would think his method would work on sharpening without the grinding.

[Matthew N. Masail]

A convex bevel is a way to get a "micro bevel" without the effect of the bevel getting steeper and\or wider each time you sharpen. it's usefulness is partly that it avoids the need for a grinding wheel unless there major damage to the blade. it works perfectly well, I personally find it much more comfortable that even the hollow grind which I used for a few years.

[Jim Matthews]

Quite right.

I find myself in the unenviable position of defending the
technique of an instructor that I would not pay tuition, again.

The technique works for me, but it's one of the few things I took away in a nine day course.
Mr. Sellers made it clear that he wasn't the inventor of most methods shown, but rather, a curator.

[ken hatch]

Quite right.

I find myself in the unenviable position of defending the
technique of an instructor that I would not pay tuition, again.

The technique works for me, but it's one of the few things I took away in a nine day course.
Mr. Sellers made it clear that he wasn't the inventor of most methods shown, but rather, a curator.

Jim,

I haven't a dog in this fight, as with most things in life somethings work for some folks, some don't. But I'm curious why there are such strong negative opinions as well as positive about Mr. Sellers. Why would you not take another class? Nine days is a long time to be unhappy, I expect I would have "walked" after a day or two if it was not what I paid for. When you are older than dirt, time is too valuable to waste.

I need to go with SWMBO to visit in-laws this year and I have been thinking about using that time in the UK to take a class from someone, PS was one of the ones I thought about. It would give me something to do and could make the near 50 hours flying steerage almost bearable or at least worthwhile. Anyway to not hijack this thread, if you would like to vent or at least give me a reason to not waste my time, how about either PMing me or start a PS thread.

Heck, Ill start a PS thread.

ken