Japanese Plane Irons

[Reed Gray]

In my journey to understand these, I now have 3, and plan to make some. I know they are hand forged, so I expect some uneven surfaces. The obsessive compulsive side of me wants to grind them all down to flat with sides parallel, and the part that sits on the wood to be flat as well. I have no problem with the back side being concave, as that is simple to deal with. However, if I am going to make some, that makes it seem like it would be impossible to do lay out without compensating for the differences in thickness of the opposite sides, and the side grooves/dados would have to be different. Is it me? is it the plane irons? Are some much better than others? Is the fitting always different for each blade?

The last Japanese style plane I got was from Woodcraft. The cutting edge is almost square to one side, and well over 1/16 out on the other side. This makes it impossible to square up the plane iron to the body. Only solution I can see thus far is to grind down the one side and then cut the edge more square to the one side. Hate to waste metal....

robo hippy

[Richard Coers]

All the Japanese planes I own have a tapered iron that wedges into the dai. I've never measured an discrepensies, so no idea how far off any surfaces are. It's been accepted for centuries that you hand fit the blade to the dai. But no one will force you to follow tradition.

[Warren Mickley]

he last Japanese style plane I got was from Woodcraft. The cutting edge is almost square to one side, and well over 1/16 out on the other side. This makes it impossible to square up the plane iron to the body. Only solution I can see thus far is to grind down the one side and then cut the edge more square to the one side. Hate to waste metal....

There has to be enough play so that the iron can be adjusted side to side so that it cuts evenly on each side. We tap the iron while it is wedged to get this just right. Traditional planes in England and America had irons with a slight taper in width, which gives even more leeway to adjust the iron side to side. You would not want to have to get the sharpening of the iron just right so the depth of cut is even with no adjustment possible.

[Edward Weber]

I'm with Richard on this.
Japanese plane irons are slightly tapered in their width as well as their thickness.
https://covingtonandsons.com/2021/04...de-adjustment/

[Reed Gray]

I am currently watching Scott Wynn's 5 part series on making a Kanna. It is helping. I do realize that the iron tapers from thick to thin by the cutting edge. The blade I am fine tuning, the sides are out of parallel by well over 1/16 inch. That is a bit much for me. For now, I have reground the bevel so it is more square to the plane, and will play some more before making a body myself.

I have seen where it is fairly common when making a western style plane to make the sides separate from the body and then glue it up, which greatly eases the hand work. I don't think I have seen this with the Japanese style planes. I would guess that the reason would be that it is not 'traditional', though I think it would work. More experimenting ahead.

robo hippy

[chuck van dyck]

I am currently watching Scott Wynn's 5 part series on making a Kanna. It is helping. I do realize that the iron tapers from thick to thin by the cutting edge. The blade I am fine tuning, the sides are out of parallel by well over 1/16 inch. That is a bit much for me. For now, I have reground the bevel so it is more square to the plane, and will play some more before making a body myself.

I have seen where it is fairly common when making a western style plane to make the sides separate from the body and then glue it up, which greatly eases the hand work. I don't think I have seen this with the Japanese style planes. I would guess that the reason would be that it is not 'traditional', though I think it would work. More experimenting ahead.

robo hippy

I feel like your approach/desire is a bit more inline with the “Krenov” style.

I’ve come to really appreciate my planes with a tapered blade only, no chip breaker or wedge.

[Reed Gray]

Well, the journey continues. The small smoothing plane I got from Woodcraft does function. I did make the sides parallel, which helps a bit. However, the resulting problem of keeping the blade square to the body of the plane is still an issue. I may have to shim one side, the other side, or both to make the plane blade more square to the bottom and able to stay in place. I was having problems with chips clogging the far edges of the blade, but solved that one by opening up the mouth a bit.

robo hippy