David C - the Text from the Second Cap Iron Paper

[D_W]

David -

Mia Iwasaki translated this (I'm pretty sure it was her) in April of 2012, I found it in my email. I recall Bill Tindall being pretty disappointed in how vague it was as he was looking for something as you are - something that provides a setting and paramaters.

Credit goes to the same professors and collegiate resources as provided with the original videos (it was important to K&K that they are credited each time their work is shared - that was relayed to me by Bill).

At any rate, here it is:

Technical Studies on Education of Orthogonal Cutting of 百九 food II Cutting force and chip length in cutting parallel to the grain by knife with cap iron by y 畠 sunoriKAWAI*，Chutaro KATO*昌 ndKenji Y AMANISHI** *Faculty of Education，Yam 昌伊 taUniversity 場 場 場 *JoetsuUniv 号 rsityof EducationSummary:

The objective of the work was to investigate the influence of capiron angle and cap iron recess on the level/quality/amount of the work on the shaving in double blade planing. The cutting force/resistance and length of shaving .
1. Average double blade resistance(planing force) increased with amount of cap iron effect compared to single blade.
2. In that occasion horizontal force starting from condition when shavings are not touching cap iron, started to show change. In vertical force, from point where shaving started to touch cap iron sufficiently the change startedto show clearly (sharp change).
3. Cutting resistance range showed the tendency to increase in accordancewith cap iron effect.
4. Shaving length is thought to be a favorable factor to determine the effectof cap iron on shaving by observation (looking at it with naked eye).
5. Also length of shaving reacted sensitively to the wear of the blade whichcould not be observed by cutting force.
6. Analyzing the use of hand planes can say:Setting cap iron can not be done by eye. Must take a test shaving and judge work(effect of) of cap iron little by little with precise adjustment. For judging, one of the methods is to measure length of shaving. [I presume that the cap iron is adjusted close, but not so close that a scrunched shaving results.]

My translation of the translation, shaving length means how the shaving straightens up out of the plane (I recall that from conversation). They liked relying on what was happening to the shaving to determine whether or not they had a good set.

For #6, I believe they were using a japanese plane, which has the iron and cap iron (or blade and subblade to appease those into the japanese planes) hidden under the wear when in the plane. I think that is why they are saying that you can't set the iron and cap iron by eye. Maybe their eyesight wasn't that good, though, I could be wrong with that guess.

In the case where you have an iron and double iron that can be affixed securely to each other, you can certainly set them by eye reliably, I have good eyesight so I can't say for sure you can do it with bad eyesight, but I think you can do it with bad eyesight and a decent light source. I have tested planes for people, and the ones that come with a flat cap iron milled precisely and finely, it's a little bit harder to differentiate the difference between the iron and cap iron. In the case of those planes, I've found it helpful to gun blue the cap iron so that it is easy to tell it apart from the iron (and then the light only shines back off of the iron). Talking about this is harder than doing, the "do" of the setting is over in 10 or 15 seconds.

I have some back and forth emails from this (this was Bill and Steve Elliot's baby, to do all of the work to dig this stuff up - their efforts and Bill was only including me to see if I thought their translations made sense from an actual use standpoint), but what I remember the gist was that the professors suggested they had trouble providing specific prescriptions for hand planes and never went into the same level of detail that they did for the machine-based testing (which, IIRC, was intended for industrial use). Or to put it more briefly, I think they decided that they couldn't come up with more specific instructions than the above, but the hand plane instructions were only an off shoot of the original study, so they weren't bothered by that.

 

[D_W]

Kees did some nice subsequent work to quantify the forces they're talking about, presumably you've seen it.

 

[Corneel]

What I understand from that paper:

When planing, the cutting action and the capiron effect tend to compress the shaving. After taking a full length stroke, the shaving will be shorter then the piece of wood. In this article they propose to use this as a guide for setting the capiron. 10% compression with a freshly sharpened iron seems to be pretty normal. If it is obviously more, then the capiron is set too close to the edge. Combined with the tearout result this could be a starting point for learning how to use the capiron. But to be honest, I think it is a rather contrived method



In these diagrams, D is the distance from the edge, S is the compression in %, N is the angle of the capiron edge for a freshly sharpened blade N(0) and after 200 meters of planing N(200). The three diagrams are for various shaving thicknesses (t).

 

[bugbear]

...a starting point for learning how to use the capiron.

Is there anything more to learning to use the cap iron (by implication "properly") than the distance back from the cutting edge?

BugBear

 

[David C]

Well thank you chaps, I now have some ideas on what to experiment with.

Best wishes,
David

 

[Phil Pascoe]

As you've not experimented before, I assume? :lol:

 

[D_W]

...a starting point for learning how to use the capiron.

Is there anything more to learning to use the cap iron (by implication "properly") than the distance back from the cutting edge?

BugBear

Nothing other than the initial preparation of the cap iron.

 

[D_W]

What I understand from that paper:

When planing, the cutting action and the capiron effect tend to compress the shaving. After taking a full length stroke, the shaving will be shorter then the piece of wood. In this article they propose to use this as a guide for setting the capiron. 10% compression with a freshly sharpened iron seems to be pretty normal. If it is obviously more, then the capiron is set too close to the edge. Combined with the tearout result this could be a starting point for learning how to use the capiron. But to be honest, I think it is a rather contrived method



In these diagrams, D is the distance from the edge, S is the compression in %, N is the angle of the capiron edge for a freshly sharpened blade N(0) and after 200 meters of planing N(200). The three diagrams are for various shaving thicknesses (t).

Thanks for the explanation, kees. I'll admit that I never thought very hard about what was written in that paper as I was expecting something more specific.

 

[Corneel]

It took some head scratching :lol:

 

[swagman]

Well thank you chaps, I now have some ideas on what to experiment with.

Best wishes,
David

Please don't do that David. There's been enough debate already on how close to set the cap iron.

Stewie;

 

[PAC1]

In relation to the translation, there can be problems with translations of technical work unless the translator is technically proficient in the subject matter (woodwork). For example their might be three words in English, one in general use, one technical for another use and the right word. A non technical translator will use the general word. Therefore unless the translation has been tested and the use of general or vague words questioned you can lose a lot in the translation.

 

[D_W]

I think that's why the translation is a bit rough here. I might see if bill can give me the original paper and then provide it to Stanley Covington to translate more smoothly.

We didn't know Stanley at the time, but he speaks Japanese and is very familiar with the tools.

 

[David C]

That's a great idea,

David

 

[BillTindall]

Hi all. I am Bill Tindall and new here. Some years ago while searching for a copy of the now famous planing video I tracked down Professors Kato and Kawai. I have corresponded with Professor Kato and he generously sent me all his scientific papers on planing as well as a copy of the video that is now widely available. (wow, this print is small and I can barely read it. No telling what I might be typing, but here goes.....)

To deal with David's submission.....I have no idea where that "translation" came from. It is a "translation" of the abstract in the paper. The original paper has an English abstract provided by the authors so there was no need to translate it. This paper was prepared as a tutorial for Kawai's students. Basically it says that when the shaving folds up like an accordion the cap iron is too close. For us, that is the only useful information in this paper.

Mia, the translator of the audio on the planing video, and the paper on wear and cutting forces, is a professional translator and woodworker and member of our club.

Kato and Kawai's work was funded by and was in support of the development of planing machines- Super Surfacers. They were mainly interested in prolonging blade life. Hence, there is work reported on the effect of cap iron on blade wear and studies on various steel alloys and blade wear as well as wear resistant coatings on the blade. None of the work investigated tear-out.

Personally, I think there is too much fuss on cap iron setting. Set it as close as you can. If the shavings scrunch up it is too close. If you get tear-out diddle with the distance until it goes away. Considering the physics of how the cap iron effect works there are too many variables to suggest one cap iron setting as best or optimum. It is an empirical journey. Accept it.

The video is NOT a tutorial on setting the cap iron. Professor Kato prepared the video for an engineering conference here in the US to demonstrate the capability of his research planing machine and photography. Many of the setting in the video never appear as settings in the planing studies as reported in the papers describing their work. Do not interpret settings in this video as recommendations.

I believe Kato and Kawai had little to say about setting a cap iron because this practice was widely used and known in Japan. There was nothing to add for the Japanese audience. Professor Kato was surprised and somewhat bewildered by the western interest in this facet of the work stirred up by the rediscovery and publication of the video in western Forums.

 

[David C]

Bill,

Thank you very much.

You are quite right. I would love something a little more precise , but will continue to experiment!

Best wishes,
David

 

[D_W]

Thanks, Bill. I'm not sure why I assumed that it had been translated by Mia. I guess if I'd have read my old emails a little more closely, that detail was probably in them. I apologize for getting that wrong.

David - I noticed as i referenced Bill to a thread that I may have implied that I couldn't measure the cap iron projection just because I didn't. The latter is true, but the former is not. I have plenty of measurement equipment such that I could measure the cap iron projection but I choose not to because it's not a good way to set the cap or become dependent on setting it as it will rope a user into limiting their range of use with a given plane.

Setting the cap by eye is easy enough that I learned to do it (before there was any kato and kawai talk anywhere and before I had seen any instruction at all, or heard there was even any) in about a week, and by two weeks, I could functionally outplane anything else I have when setting only by eye.

This is a great skill to teach students to do by eye, because it's easy to do it. As long as you can see. More important when instructing them is to make sure that their cap irons and iron backs have some contrast so they can see the metal on the back of the iron, and teach them to turn until the light reflects off of it. If they have a modern cap iron that has two flat planes intersecting, both polished, then apply some gun blue or black marker to the cap iron so that it is dulled, darker and contrasting to the back of the iron.

 

[swagman]

Professor Yasunori Kawai and Honorary Professor Chutaro
Kato, Faculty of Education, Art and Science, Yamagata University.

http://www.solidwoodmachinery.com/supersurfacers.htm