Hammer Handling

by Mathieu

In december last year I was traveling in Japan together with a friend. At the time he was apprenticing with a daiku (carpenter) in Enzan, Yamanashi prefecture. During this trip I was overwhelmed with so much kindness of all the people we encountered. To this day I am still amazed by all the nice things people did for us. My friend proved to be a very enjoyable travel companion as well and since he is fluent in Japanese there is no doubt that his translating skills contributed to the good experience I had.

On top of all those nice experiences I received some beautiful gifts and one of them was a hammerhead made by the late blacksmith Hasegawa Kouzaburo who passed away in november 2004, given to me by my friend. A couple of days later we visited a tool dealer which had some very nice genno on display in his shop. Besides the hammerheads themselves I was fascinated by the  handles which where fitted to them. I have made some handles in the past but I found these inspiring for future handle projects.

The second one from the top is made from Gumi, my favorite wood for handles. I have no idea what wood is used for the short handle on top but I like the bark that is left at the end. More bark would have been even nicer, although I am not sure if it would be gentle on your skin while using it intensively. It all depends on the structure of the bark. On another one of my hammerheads, made by Masayuki, I have fitted a handle of Madrone. I left some of the bark on it which is as smooth as skin and feels really nice while using it. The bottom one is made out of Japanese White Oak and intrigued me because of it’s shape. I asked the shop owner if I could see them to investigate their shape a little better.

Last year I made a similar curved handle out of Black Locust for my funate-genno made by Hiroki. Personally I really like a slightly curved handle because it is comfortable when you are pounding on a chisel and it also tells you where the straight or rounded face is without having to look at it first. You just feel wether you are holding it right. The rounded face of a genno is often used to compress the wood fibers, this is done to ease the assembly of tight joints. Because of the moisture in the air, the wood fibers swell back and this establishes a very good fit.

The curved handle shown in the first picture felt so good in my hand that I decided to copy it for the Kouzaburo hammerhead I got as a present. I was amazed by the thinness of the handles I saw and it is because they are so thin that they felt good in my small hands.

Especially the Gumi handle flares out quite a bit towards the end, I like this widening to be a little more subtle. Before I left the shop I copied the shape of the White Oak handle on a handle blank so I could make one for myself later. It is not visible on the picture but none of these handles where fitted to the head using wedges to secure them. I have tried to do this in the past but they always came loose again and at some point I had to wedge them anyway to secure them. I knew that, when done correctly, they shouldn’t need a wedge and would be secured for a very long time.

I shaped the piece that I brought back from Japan roughly with a rasp. Then I scraped the surface to a smooth finish leaving the top of the handle a little bit too wide and thick, about 2mm in both directions. I should have documented the whole process but when I am working I never think about taking pictures. I will try to remember next time.

In the book ‘The Soul of a Tree’ by Nakashima I saw a picture of how they dry out tenons with a ultraviolet heating lamp to shrink them to minimum size before the tenon is inserted in the mortise. I decided to use this approach in the hope I would be able to fit the handle super tight without a wedge. I left the top of the handle in front of the lamp for about 24 hours and I guessed that should be enough to have it shrink sufficiently. At first it seemed that the handle needed to be shaved down a little more but with gentle persuasion I was able to insert the chamfered handle top into the hole by just a millimeter.

The hole of the hammerhead needs some explanation. With a good quality genno the hole is flared outwards towards the top. This does enable you to fit a handle to it without the need for a wedge. Also the bottom side of the hole, where you insert the handle, has a small chamfer on it. This prevents the wood to tear off while inserting the handle. On the pictures below this chamfer is not visible since the wood has swollen back and covers this chamfer.

As soon as the handle is inserted you can drive it down deeper by pounding the bottom with a wooden mallet while you hold the handle in your hand. Don’t place it onto a bench, inertia will drive the head onto the handle. I found the color a little pale in combination with the old used head and decided to smoke it with some ammonia before applying pure Camellia oil onto it. With pure I mean pure. Here you see the bits of the Camellia nut which I used to rub the oil into the wood surface.

This is the result. I like how the shape turned out and it feels just right.

Just a gentle widening et the bottom part.

Tools always look so much better after a couple years of intense use and good maintenance. So let’s put this clump of steel to use…