I never found any value in the ruler trick for plane irons

[Kees Heiden]

There is a whole range of sharpness levels between dull and "sub micron shavings in one of these Japanese planing contests". The amount of attention paid to the back of a blade is one aspect in this range.

In a plane you get a backside wear bevel that can be a very obvious shining line along the edge. This wear bevel is the result of the shaving gliding over the back of the blade. Do you need to remove it? Well, that depends on the level of sharpness you are shooting for. The shavings allready polished the back of the blade quite a bit. Not Shapton 30 000 grit polish, but still quite good. The shinyness of this line is an indicator that it isn't so bad at all.

When you sharpen the bevel, especially on an oilstone, you get a substantial burr, leaning over to the backside. Pushing the back over the stone bends this burr back to the bevel side again, even without really touching the wear bevel at all. A bit of back and forth between bevel and back side bends the burr enough to weaken it so it breaks off. Then a bit of stropping removes even more remnants of this burr.

I think this is why craftsman of old could get away with a pretty hasty sharpening regime, without ever really touching up the back or even flattening it . They weren't producing the sharpest ever edges with this method, but still good enough for their work. I suppose even back then there were heated debates in the pub on this subject, if they didn't have anything more usefull to discuss.

[ken hatch]

There is a whole range of sharpness levels between dull and "sub micron shavings in one of these Japanese planing contests". The amount of attention paid to the back of a blade is one aspect in this range.

In a plane you get a backside wear bevel that can be a very obvious shining line along the edge. This wear bevel is the result of the shaving gliding over the back of the blade. Do you need to remove it? Well, that depends on the level of sharpness you are shooting for. The shavings allready polished the back of the blade quite a bit. Not Shapton 30 000 grit polish, but still quite good. The shinyness of this line is an indicator that it isn't so bad at all.

When you sharpen the bevel, especially on an oilstone, you get a substantial burr, leaning over to the backside. Pushing the back over the stone bends this burr back to the bevel side again, even without really touching the wear bevel at all. A bit of back and forth between bevel and back side bends the burr enough to weaken it so it breaks off. Then a bit of stropping removes even more remnants of this burr.

I think this is why craftsman of old could get away with a pretty hasty sharpening regime, without ever really touching up the back or even flattening it . They weren't producing the sharpest ever edges with this method, but still good enough for their work. I suppose even back then there were heated debates in the pub on this subject, if they didn't have anything more usefull to discuss.

Especially if they were Scottish craftsmen.

ken

P.S. Good post Kees. Sharp enough is just that....Sharp enough for the work to be done. With water stones the "ruler trick" (BTW, I hate that term) can help get there for most uses.

[Warren Mickley]

T

When you sharpen the bevel, especially on an oilstone, you get a substantial burr, leaning over to the backside. Pushing the back over the stone bends this burr back to the bevel side again, even without really touching the wear bevel at all. A bit of back and forth between bevel and back side bends the burr enough to weaken it so it breaks off. Then a bit of stropping removes even more remnants of this burr.

I think this is why craftsman of old could get away with a pretty hasty sharpening regime, without ever really touching up the back or even flattening it . They weren't producing the sharpest ever edges with this method, but still good enough for their work. I suppose even back then there were heated debates in the pub on this subject, if they didn't have anything more usefull to discuss.

When you talk about "craftsman of old", are you talking about guys in 1965, when Paul Sellers was being trained, or are talking about guys in 1780, when Peter Nicholson was being trained? If you are talking about craftsmen in the 18th century not flattening backs, I would be interested in any documentation.

[Kees Heiden]

No of course there is no documentation of lazyness. Nicholson documented how it should be done. The last handtool woodworkers, teached around WW2 told us about methods like where they would rip of the burr by pulling the edge through a piece of wood. Have you ever found an old tool showing signs of carefully flattened backs? Even the Seaton chest chisels are not very flat. BTW, I quickly scanned through Nicholson and found nothing about the back of the blade in the sharpening section. Only the "bezel" is mentioned.

For sure, I don't think every craftsman was hasty or lazy and especially in the upper echolons I supose they where neater then in a country carpenters shop.

Then there is also "experimental archeology". When I sharpen a plane blade like explained above, I get a usefull edge.

That, and I don't believe in the infallibility of mankind.

[Kees Heiden]

I would say Nicholson is suspect too. He advocates the dreadfull shortcut of the micro bezel!

[Jim Koepke]

If you are talking about craftsmen in the 18th century not flattening backs, I would be interested in any documentation.

My thinking on this may be wrong, but in the 18th century wasn't one of the first things an apprentice learned was taking care of their master's tools? Maybe the 'craftsmen' of the 18th century didn't flatten their edge tool backs because it was done by the apprentices working around them.


If one is removing shavings in bulk a little wear bevel isn’t a major problem. It may cause a need for more effort by the user.

For a smoother, wear bevels may be uneven. One may want to avoid this unevenness on their finished surface. This becomes a reason to sharpen more often.

Sharpening often can lead to sharpening less.

jtk

[Kees Heiden]

Wait a sec! I do have documentation!

Holtzappfl, volume 2 of Turning and Mechanical Manipulation, Chapter 23, section 4.

Sharp.jpg

[James Pallas]

No of course there is no documentation of lazyness. Nicholson documented how it should be done. The last handtool woodworkers, teached around WW2 told us about methods like where they would rip of the burr by pulling the edge through a piece of wood. Have you ever found an old tool showing signs of carefully flattened backs? Even the Seaton chest chisels are not very flat. BTW, I quickly scanned through Nicholson and found nothing about the back of the blade in the sharpening section. Only the "bezel" is mentioned.

For sure, I don't think every craftsman was hasty or lazy and especially in the upper echolons I supose they where neater then in a country carpenters shop.

Then there is also "experimental archeology". When I sharpen a plane blade like explained above, I get a usefull edge.

That, and I don't believe in the infallibility of mankind.

You've got it Kees. They tool makers of the past and now I'm talking about Bailey and Stanley and others would have been flattening backs if that is what craftsmen demanded. That flat back thing came serious in my lifetime. They had the tooling and the technology to do it. They could taper saw plates to thousands of an inch and the like because it sold saws. They continuously improved planes until they went out of the hands of workers. If the so called ruler trick took hold the new makers of planes wouldn't be flattening backs today. I'm not talking about cheap ones. I have to be with Kees on this one. Because of some writer of text books says something it must be so. We can't go back and watch what was actually happening in the shops of old to be sure but I don't think the flat back was lost any more than the chip breaker thing was lost. I wonder what will be said about us 200 years from now. Maybe that we waxed our cars to make them go faster instead of just look good.
Jim

[lowell holmes]

I thought the ruler trick was to get rid of the burr on the back of the bevel. You shouldn't see a back bevel.

[Warren Mickley]

Wait a sec! I do have documentation!

Holtzappfl, volume 2 of Turning and Mechanical Manipulation, Chapter 23, section 4.

Sharp.jpg

Yes, the FLAT face of the iron is laid quite flat on the oilstone. That is a long way from what you said earlier:

"without ever really touching up the back or even flattening it ."

[Simon MacGowen]

After some 40 posts, we still don't know what the OP actually has experienced: a ruler-tricked blade bought brand new (from whomever we still don't know), or something else. I have yet to find a vendor who sells ruler-tricked irons. Anyone?

Simon

[Kees Heiden]

Yes, the FLAT face of the iron is laid quite flat on the oilstone.

“To remove the wire edge”

Nowhere in old documentation is mentioned that a new tool should be flattened, and on old tools we don’t often find the evidence.

In the end it’s all interpretation. I understand the term “flat face of the iron” as oposed to the beveled face. Not that the author neccessarily means a mirror.

[Warren West]

if they didn't have anything more usefull to discuss.

The more things change, the more things stay the same.

[Chris Parks]

After some 40 posts, we still don't know what the OP actually has experienced: a ruler-tricked blade bought brand new (from whomever we still don't know), or something else. I have yet to find a vendor who sells ruler-tricked irons. Anyone?

Simon

Common sense says why would they bother.

[Sean Tracey]

Sean,

What brand is the plane?

I've never heard of a manufacturer deliberately back beveling a plane iron. It doesn't even make any sense that they would do that (customer pref, added cost, etc.).

Way more likely the plane wasn't flattened all the way to the edge.

I'm pretty sure if you call the manufacturer they will tell you this.

I agree that it does not make sense to ruler trick a brand new plane iron with a certain caveat which I will get to later. This also played into my surprise upon finding the ruler tricked new iron.

But it was definitely ruler tricked to a decently fine stone as the sharpening pattern was across the width of the blade. The blade was honed perfectly flat from blade tip to where the angle of ruler tricking lifts the blade from the stone. The ruler tricking and honing of the blade were top notch quality and effectiveness. I bought the plane well more than 5 years ago, maybe more than 8 years ago. It is an iron body #4 of high quality manufacture. It cut perfect right out of the box with no sharpening needed. I really like the plane and was able to plane twisted boards flat with no real experience. Very satisfying. I discovered the ruler tricking when I went to sharpen it the first time. I was mildly miffed, but since it was already done, I knew that the fast way to keep using the plane was to continue to ruler trick it. My stones are not as wide as the factories, so my ruler tricking flat area was definitely narrower than the factory flattening.

I believe from the manufacturers point of view ruler tricking makes sense. It allows them to provide an actually perfectly honed (not merely rough ground) iron. I believe the manufacturer has found that the majority of purchasers are going to try the plane right out of the box. If the plane cuts well out the box, then customer satisfaction will be maximized. A very sharp blade is a major key for accomplishing good performance, and I believe the fastest way to provide custom honed blades is to ruler trick the blade. When the iron get's dull, now the customer knows the plane needs sharpening and will have to learn to do so and will also be less likely to fault the plane if their sharpening skills are not up to the high standards of the original factory sharpening.

My comments are not meant to be a criticism of the manufacturer, they provided a well made plane with a hand honed iron of excellent sharpness. If I had to hand hone hundreds of irons, I could definitely see the advantage of ruler tricking. If I had a really badly pitted old iron, I could see that ruler tricking may be the only practical way to get a good restoration. But I don't see the advantage of ruler tricking for an individual who works with planes. You flatten the back one time which takes a bit longer than ruler tricking, but I find it much easier on every subsequent sharpening to have a flat back.

The point of my post was mostly to find out what others thought of ruler tricking. It's been informative. Now that my sharpening technique is all worked out, I definitely prefer a flat backed iron.