Did oldtime craftsman flatten their plane irons?

[Patrick Chase]

My apologies for the self-reply, but...

I've used the Spyderco ultra-fines for decades for ski tuning and more recently for woodworking, and there's no way you're going to convince me that's equivalent to a 6000# stone. Maybe 3K based on careful examination of scratch patterns (you can't judge anything from the "feel" of the stone IMO).

Upon reflection, this is probably more a matter of which grit systems Derek and I are applying than a real difference in opinion. Various sources put the Spyderco UF at the eqiuvalent of ~3 um particle size (though it's hard to directly compare).

If you use the "Shapton scale" 3 um would correspond to #5000, or pretty close to what Derek said.

If you use the latest version of the JIS standard as do Sigma and Imanishi, it would be a #3000 or so.

In either case I agree with Derek's bottom line - The Spyderco UF leaves useful sharpness on the table. My comment about getting some benefit up to "10000# or so" probably should have been worded "1 micron or so".

[Warren Mickley]

In 1796 Benjamin Seaton purchased a Turkey oilstone for 8s, two days wages. For the same amount, 8s, he also bought 8 oval bolster mortise chisels (7 for $544 at tfww). Five beech hollows and rounds ($1000 from Bickford) cost less than two days wages. A double iron trying plane and a double iron fore plane together cost 8s also. The evidence is that Seaton valued the oil stone highly and when you look at his work it is obvious that he was rewarded with a good edge. The Turkey stone, a novaculite similar to Arkansas stone, was being shipped in the 1st century and it was being shipped in the 11th century. By the mid 18th century, Roubo was complaining about declining quality and high cost.

Here is a picture by Tim Zowada of a razor honed by an Arkansas stone (called 6000 by some in this thread).
ZowadaTransArkSm.jpg
Here is a picture of the so called Shapton 15K
zowada Shapton15kSm.jpg

Earlier in this discussion Stanley Covington wrote

My answer to Derek's Question No.2: Ha ha! I like the way you twisted the question. 6000 grit is fine for many tools especially where quick and dirty work is required. But even if a 6000 equivalent grit oilstone would produce an adequate edge, they are just too damned slow compared to a synthetic waterstone. So yes, I am reluctant to change.

I have to wonder how long it takes him to sharpen a chisel using his methods.

[Daniel Rode]

Here's a question or three: if you come to the conclusion that cabinetmaker's of yesteryear honed the bevel alone and "sort of" removed the wire, without any effort to work the back of the blades .... would you change your current sharpening regimes and do the same?

...

Derek

Yes. I would definitely give it a try. If I got the results I need with less effort or less cost, I'd switch. I like to be as practical as possible with tools and sharpening. I want to work wood and not spend unnecessary time fettling tools.

The "craftsmen of yesteryear" idea is itself an interesting one. Which craftsmen, what era and what quality? A marginal carpenter from perhaps 1900 or later might have crude tools and be able to complete his work. On the other hand, a highly skilled cabinet maker from 1800 would require refined tools and processes to create top quality furniture.

I can probably learn something from both, but it's the latter really I'm interested in. I suspect that represents the zenith of hand tool woodworking. What did he do and why did he do it? If he sharpened to #6000 on a dished oilstone, I want to know how and why. Perhaps that was the finest stone he could get and would have been thrilled with a #16000 shapton.

[Phil Mueller]

Thank you all for this post. Our local fire code requires i do a 90 minute test of the emergency lighting system. Reading and pondering this subject made the time sitting in relative darkness fly by . In addition, I found the more pressing question to be; if I dress better, will my work improve?

[Patrick Chase]

In 1796 Benjamin Seaton purchased a Turkey oilstone for 8s, two days wages. For the same amount, 8s, he also bought 8 oval bolster mortise chisels (7 for $544 at tfww). Five beech hollows and rounds ($1000 from Bickford) cost less than two days wages. A double iron trying plane and a double iron fore plane together cost 8s also. The evidence is that Seaton valued the oil stone highly and when you look at his work it is obvious that he was rewarded with a good edge. The Turkey stone, a novaculite similar to Arkansas stone, was being shipped in the 1st century and it was being shipped in the 11th century. By the mid 18th century, Roubo was complaining about declining quality and high cost.

Here is a picture by Tim Zowada of a razor honed by an Arkansas stone (called 6000 by some in this thread).
ZowadaTransArkSm.jpg
Here is a picture of the so called Shapton 15K
zowada Shapton15kSm.jpg

Earlier in this discussion Stanley Covington wrote

I have to wonder how long it takes him to sharpen a chisel using his methods.

The thing that hasn't been discussed adequately here is wear and resulting grain variability. Arkansas stones have very hard bonds, such that worn abrasive remains in situ and the effective grit # of the stone as a whole increases with use. I think that when most people assign a grit # to Ark stones they're talking about its pristine, as-cut/lapped state. I've seen plenty of (older) sources which state that that's too coarse and that finishing Arkansas stones must be "broken in" before they'll produce an adequate edge.

While I'm not really a fan of Shapton, that "15K" shot doesn't look kosher. The fact that the grooves are deepest away from the edge and then become shallow as they approch it suggests to me that he failed to remove all of the striations from a previous, lower-grit stone. If those striations were all from the (final) finishing stone then they should run continuously to the edge, but they don't.

[Jim Koepke]

The trouble is, one does not know if the vintage blades we find in this condition come from a professional or an amateur. It makes it difficult to conclude anything.

+1 on what Derek said.

Most carpenters likely had a #4 or #5 for the day to day need of trimming the edge of a door or to smooth down a high spot in a floor board.

They likely didn't take as much trouble with their blades as a cabinet or furniture maker.

jtk

[Derek Cohen]

The Turkey stone, a novaculite similar to Arkansas stone, was being shipped in the 1st century and it was being shipped in the 11th century.

A bit slow. They must have been using UPS.

Regards from Perth

Derek

[Kees Heiden]

Hi Warren, nice pictures. I think I know that site, it is very high tech! BTW I am very happy with an Arkansas but I do also strop after that one. In my hands it is easier to remove the wire edge with a strop.

Benjamin Seaton sure invested quite a bit in his sharpening setup. But did he flatten his chisels and plane irons? There are a few with a convexity according to the drawings in the back of the book. A lot are slightly concave, which is ideal when you buy a new chisel.

[david charlesworth]

I see many people misinterpreting the ruler trick.

A double iron blade is best, when flat across the width, adjacent to the edge, so that the chipbreaker may fit, and avoid shavings jamming and causing choking. (There is a technique of burnishing the c/b edge to close gaps, would this work on an out of flat blade?)

This flattening can be done on a coarse stone approx 800 or 1.000 grit.

The ruler trick, done on a polishing stone such as 6,8.10,000 grit creates a narrow band of high polish. This ensures very good sharpness. It saves some work at set up, but this is not the principle reason for using it.

One of the main points of the ruler trick, is that the probability of the edge touching the stone, is massively increased. This means the wire edge is honed away, and usually floats off on the stone or the sponge cloth. No need for stropping.

Just to expand the probability argument, what are the chances that the blade back and stone surface are perfectly flat??

Some have suggested random slight lifting on the polishing stone, but this throws out any idea of repeatability.

I'm sure a non flat blade can be sharpened.

The wire edge, which is not honed away, is torn off and the resulting mess is improved by much stropping. Maybe this works well?

Best wishes,
David Charlesworth

[Jim Koepke]

I'm sure a non flat blade can be sharpened.

That is good news for all of us who use gouges.

jtk

[Jim Koepke]

A thought that comes to me on this is when did the apprentice era end?

Wasn't one of the first duties of an apprentice to sharpen the tools of the journeyman workers?

jtk

[Kees Heiden]

Why would the wire edge been "torn off, resulting in a mess"? It is first weakened to a large degree on the polishing stone, then bent back and forth until it breaks of cleanly. That bending back and forth can be done on the polishing stone or with a strop. The strop polishes even more, right at the edge and creates a very smooth but slightly more bulbous edge That's what I think is happening, but you need an electron miscroscope to proove it. Or you rely on the very sharp edges this technique creates.

[Warren Mickley]

T
While I'm not really a fan of Shapton, that "15K" shot doesn't look kosher. The fact that the grooves are deepest away from the edge and then become shallow as they approch it suggests to me that he failed to remove all of the striations from a previous, lower-grit stone. If those striations were all from the (final) finishing stone then they should run continuously to the edge, but they don't.

Not Kosher? or not the evidence Patrick Chase wants to see?

[Nicholas Lawrence]

i'd add that if you are using a chip breaker set real close to the edge(like they need to be),the iron had better be flat. The slightest sliver of an opening between the chip breaker and the iron will cause chips to get wedged in there slightly less fast than the spaceship Enterprise can reach light speed.

Who knew George was a Trekkie? Would not have been my first guess.

I find this argument convincing though. I am pretty well persuaded the purpose of the double iron was to control tear out. I just don't see another good reason for the development of double iron wooden planes with those massively thick (by modern standards) irons. And if you accept that the double iron was used closely set to reduce tear out, you pretty much have to conclude people flattened the backs of the irons.

Now obviously not everyone flattened the backs, just like not everyone used their chisels for something other than opening paint cans. But I think the better craftsmen must have.

[Patrick Chase]

Not Kosher? or not the evidence Patrick Chase wants to see?

Not consistent with what I see under a scope and what I've seen in SEM shots from sources I trust (Leonard Lee's book for example).

The Shapton 15K is drastically over-spec'ed (if we take Shapton's own stated grit diameter as gospel then it would be a 10K in most other stone lines), but isn't *that* different from my translucent or black surgical arks, even when both of those are well-worn.

Also and as I said, the fact that the scratches "taper" approach the edge is strongly indicative of bad technique, because it's a near-certain indicator that they were left by a previous, coarser stone and only partially polished out. You never see that when the surface is fully polished such that it's entirely the product of a single stone.