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Koyamaichi Dovetail Chisels

The best part of woodworking is joint making. And the most pleasurable joint to make is a dovetail.

Several years ago I managed to pick up 4 Koyamaichi dovetail chisels on eBay at what I considered to be a bargain price. NOS 1980 stock - 1", 3/4", 1/2" and 3/16". I had heard about Koyamaichi from David Charlesworth, who gave them two thumbs up. I looked all over for them, but no one stocked Koyamaichi. Some years later
Lee Valley began to offer them, and they were the only stockist ... until I heard from Stu (in Japan) that he had met Mr Koyama, and was now offering them as well.

When Stu contacted me it was amazing timing. Let me explain ...

Japanese dovetail chisels are really only called "dovetail chisels" because of their shape, and not because they are designed to chop out dovetails. They are tapered from the top, but they do not have narrow shoulders. Certainly nothing like Lie-Nielsen or Blue Spruce. The Koyamaichi are pretty good in this respect, but only compared to the regular bench chisels.

I have other dovetail chisels. The Blue Spruce are fantastic, however they are purely for pushing, and it pays to have a chisel that can be used to chop into hard wood when you live in Oz. The Koyamaichi excelled at this, taking and holding a fantastic edge. I gather that they are white steel (#2).

I am a compulsive tinkerer. Never leave anything alone. And a while back I decided to grind down the sides of the smaller Koyamaichi chisel so that it could chop out the waste right into the shoulder but without bruising it. And I screwed it up ... gouged out a piece at the top. The chisel was OK to use but every time I looked at it I was reminded that I had done a poor job.

When Stu emailed me I decided to get a replacement for the 3/16" as well as a 1/4" and a 1/8" to round out a set. Not only that - and this is really the point - but Mr Koyama would custom grind the shoulders to my specs. Well, I could not pass up the opportunity.

As seen below, there is a difference in the looks of the old and the new. Now will this be reflected in their quality as well?

Originals or the left, new on the right

Here are the shoulders of the original three ...

.. and here are the shoulders of the new three ...

The shoulders are very tiny, less than 0.5mm - I had planned to lap these out with sandpaper, but a stroke from a Dremel, and this was gone. Very little work needed.

The hoops of the original chisels were hand beaten rather than forged. I liked that look so Mr Koyama added these to the new chisels (note – these were sent separately and I needed to set them myself). The hoops were finished in black, which I buffed to steel to match the originals.

In use (this is the important bit) ..

The chisels worked well .. the new chisels appears to be as good as the old chisels at getting sharp and holding an edge. I cannot emphasize enough that this means very sharp and very durable … better than any Western chisel I have used to date. All this and they were easy to sharpen on my Shapton waterstones (about the same as my Stanley 750s).

Nice balance.

With these modified blades I was able to get a tight fit at the shoulder ..

I had a length of unusual Radiata Pine that I discovered in a pile at the local Bunnings …

and paired with Jarrah it made for an interesting box to show off some 1/8” wide dovetails ..

The hard, abrasive Jarrah was cut easily and failed to dim the edge of the steel.

After some weeks of use all can say is that these are great chisels – beautifully made, well balanced, durable and a joy to use. They will be around a long while.

Regards from Perth


January 2010