Chip Breakers
Bob Strawn, in an excellent article about his take on the Kawai-Kato video:
For an occasional craftsman who dreads taking a blade out or adjusting a plane, a top iron is horrid. For a craftsman who has a hundred planes on the wall, a top iron may be just another thing to fiddle with while trying to do work. For a craftsman with less than a dozen planes, or a craftsman who carries his tools, I believe that it is well worth his time to learn how to use a double iron.
Even more impressively, in this article Bob describes how he came from a place where he did not like chip breakers to where he knows how to use them well. The impressive thing is that Bob had the cojones to talk publicly about how he changed his mind.
In my day job, where I am on faculty at the medical school, I know from teaching medical students how to have the insight to know when their previous ideas may not be entirely correct and to adjust their practice is one of the hardest things for someone to learn how to do. So kudos to Bob for being brave enough to say this in public. Many of us never learn this skill. And it’s a more valuable skill than knowing how to set up and use a chipbreaker.
Which I have to start learning how to do, myself. I’m also in the “chipbreakers are useless” camp. But probably not for long.
This is the full version of the video created by Professor Yasunori Kawai and Honorary Professor Chutaro Kato at Yamagata University, as part of their research in the role of cap irons in planing. Mia Iwasaki did the initial translation of the audio and captions in this video, after which I edited the translation and added subtitles to the video.
In this video, the setup of the experiments is more fully described, and the comments are directly from Professors Kawai and Kato, rather than my own guesses as to what was going on. I’m just happy that I wasn’t more off in my interpretations than I was.
This is fascinating, and the whole video is well worth the watch, even if you’ve already seen the excerpts previously posted.
(Thanks again to Bill Tindall for his role in obtaining a copy of this video and the permission from Professors Kawai and Kato to share it, and to Mia Iwasaki for her translating. And thanks to Professors Kawai and Kato for generously sharing their work.)
Source: kegaki.kj.yamagata-u.ac.jp
This is the last sequence from Professors Kawai and Kato’s video on planing. This segment shows what happens when the angle of the cap iron is steepened to 80º. To my eyes, at this point the plane blade is acting very much like a scraper. Tearout seems to be further reduced.
One last time: my captions, no knowledge of Japanese, could be way off in terms of the text, etc.
(Thanks again to Bill Tindall for tracking this video down.)
Source: kegaki.kj.yamagata-u.ac.jp
This is the next sequence of from Professors Kawai and Kato’s video on planing. This segment shows what happens when a cap iron with a 50º bevel is placed at varying distances from the edge of the plane blade when planing against the grain. The cap iron does mitigate the tearout seen in the previous video, although it looks like it has to be very close to the edge for optimal results.
Again, the captions are mine, I don’t know Japanese, probably could be way off in terms of the text, etc.
(Thanks again to Bill Tindall for tracking this video down.)
Source: kegaki.kj.yamagata-u.ac.jp
This phenomenal video of a microscopic view of what happens when a plane blade cuts wood was created by Professor Yasunori Kawai and Honorary Professor Chutaro Kato at Yamagata University, as part of their research in the role of cap irons in planing. This segment shows a plane blade without a cap iron, planing with the grain, then against the grain, and finally taking a thinner shaving against the grain.
The captions in the video are mine, and are my take on what I am seeing in the video. I will fully admit that I don’t know Japanese at all, and so the captions should in no way be taken as a translation of the text seen in the video. In fact, I may be completely off in my comments compared to what the text says.
(Thanks to Bill Tindall for tracking this video down.)
Source: kegaki.kj.yamagata-u.ac.jp
Tapping Out a Western Plane Blade
Japanese and western woodworking tools have nothing in common.
Japanese plane five ways
Most Japanese planes have some sort of western counterpart. There are Japanese versions of smoothing planes, jointers, plow planes, chamfer planes, and so on. This is a Japanese plane that really doesn’t have a western equivalent. It’s called a gotoku kanna, or five purpose plane, according to the translations I have read.
The plane has a body that looks like an inverted T, and the blade runs across the width of the plane.
This plane gets its name from the fact that it can serve five purposes: left sided rabbet plane, right-sided rabbet plane, left grooving plane, right grooving plane, and a smoother, as can be seen in the following pictures.
The gotoku kanna does an admirable job in four out of the five functions. It cleans rabbets and trims side walls of rabbets and grooves on the left and right very nicely. But as a smoother, well, it really kind of sucks. As the plane takes a shaving, there really isn’t anywhere for the shaving to go, as it gets caught up under the middle of the plane. The shaving gets jammed up, and it’s a pain to get it out.
Four out of five makes it a B-minus student, or, one grade below an Asian F. But I have to admire the gizmosity factor in combining all of these functions into one plane.
John Reed Fox: The Uncompromising Craftsman - Fine Woodworking
John Reed Fox:
If you want to have the hand skills that it takes to do this, you have to do it a lot. There’s just no other way. You have to spend a lot of time at it. The way to learn how to cut dovetails is to cut dovetails. The way you learn how to sharpen is to sharpen.
Rather than being intimidated by this, I think there’s comfort in the fact that practice is all it takes.
It is completely worth the six minutes it takes to watch the accompanying video, and listen to John Reed Fox talk about his work. I would love to meet him someday. My one link with John Reed Fox is that he made the body of the plane I used to illustrate the set up of a Japanese plane.
