Wednesday, February 15, 2006
- basic maths (when you compute compound angles for example)
- physics and chemistry (relating to metalurgy, grain of sharpening stones, measure of the degree of humidity degree in the wood, wood composition, ...),
- mechanics (if you want to study how the plane blade interacts with the wood, ...),
- biology and ecology,
- history (when studying the origins of tools,...),
- and of course manual work.
But no matter how much you study wood properties or design, whatever how long you have been practicing planing or sawing or chopping, one thing is primordial: sharp tools.
Planing with a dull blade is like riding a formula one race with worn out tires. I'm not an F1 specialist but I know how important tires are, and they are changed a significant number of times during a race.
I remember one of my relative who was using the side of a cement wall to sharpen his kitchen knife. The cement was smooth after repeating sharpening over many years. But the surface was not flat at all, and still presenting sand grains or other particles. Now compare this cement wall with a 15000grit shapton stone...
Fortunately we have a wide choice when it comes to sharpening media: from natural to man made stones, compound to diamond paste, leather strops, mechanical tools...
The sharpening media goes by pair with the tool. Some time ago I spend hours on a blade, that wouldn't take any edge. I gave up. Then I went to Japan and shown the blade to Mr Sugimura (who has an impressive sharpening corner). After sharpening another blade I had also brought him, he started to work on the one I thought difficult. He spent 3 mn on it and said: "veeerrry difficult sharpen". It was a revelation for me: though I new by readings that some blade are hard to sharpen, I didn't know I had had the experimence myself. I just thought I was doing something wrong.
Sharpening is the art of feeling (the blade contact with the stone, its sharpness), listening (the scratch noise produced on the stone of a given grit) and looking (the blade dullness, because when an edge is sharp, you don't see it). And through experience, you'll know which stone you have to use for which blade (i.e which steel).
Books have been written on the subject, some are excellent. So the purpose of my writings here are just to share my thoughts on the matter, I won't reach the level of specialists.
I hope however to gather enough material from my own experience to provide basic guidelines and show what I do with what I have.
i found this link from another wood site.. and i am interesting in japanese hand plane..and want to make one myself. any help will be graceful...thanks
If you want to make a Japanese tool yourself, the best place to start is to buy one and observe how it is made. Also, the book Japanese tools by Toshio Odate shows a diagram of how a "dai" is made.
Things to take into considerations are the fact that the blade is tapered from top to bottom, both on the side and the face.