Craftsmanship in Wood

Consider that the tool would have poor functionality if the blade were narrower than the body. Each pass would leave a portion of uncut material in the inner corner of the dado.

If the blade were exactly the width of the body, then you are depending upon the body not to shrink or swell. The only choice is to make the blade sides slightly proud, and indeed, as Mathieu noted, it is the only way the tool will work without the dai getting tight in the groove.

Also keep in mind that the trimming of the groove sidewalls is to be accomplished with a separate type of plane.

Yes, of course the blade must be proud. My curiosity was more towards how proud is considered adequate. It's interesting to me that many of the western grooving planes I see, metal-bodied particularly, have flush blades. Perhaps they are only expected to make shallow grooves?

Wakitori kanna are tools I have no experience with yet, though I hope to eventually. The tolerances for their setup seem somewhat demanding.

dmccurtis wrote:Yes, of course the blade must be proud. My curiosity was more towards how proud is considered adequate. It's interesting to me that many of the western grooving planes I see, metal-bodied particularly, have flush blades. Perhaps they are only expected to make shallow grooves?

Wakitori kanna are tools I have no experience with yet, though I hope to eventually. The tolerances for their setup seem somewhat demanding.

There's a difference of sorts between a grooving plane and a bottom cleaning plane. Grooves are generally for panels and I would imagine that 3/8", 10mm or so, would be about as deep as things need to go. Japanese grooving planes similarly only cut about that deep. I think even with those planes the blade would have to be hair fatter than the surrounding male tongue on the plane.

The bottom cleaning plane is more general purpose, for rebates and dadoes, and really can go pretty deep.

The Veritas shoulder plane also has the blade slightly proud of the body.

As for wakitori ganna, yep, they are tough little critters to set up. There's a couple of different styles, one similar to half of a gotoku ganna.

That distinction makes sense. I have a couple of kikai shakuri (jakuri? What's the accepted romanization?) ganna, and their blades are slightly proud of the tongue, and the knives proud slightly further. Their maximum depth of cut is roughly equal to their blade width, which seems a deliberate ratio.

I've seen both styles of wakitori ganna, and wondered which to get. I could see no obvious advantage to either style.

I do have a peculiar fondness for gotoku ganna. I recognize that it's probably not as effective as a set of side trimming planes, but it's just such a uniquely cool tool. I've resisted buying one on numerous occasions. Just as well, as I suspect it is probably more useful as a carpentry tool than for furniture.