What is this used for?

[Roy Lindberry]

Ok, my first post is a question for all of you....

I recently got three moulding planes, and am not sure what one of them is for. Hopefully you guys can help me figure out what it is, and what it is missing.

The iron is skewed and only covers the lower part of the profile. Up front is a mortise that looks like it is for a knicker or another iron for the other side of the profile, but I've never seen a vertical iron (outside of a knicker).

Basically, with the iron that is in it, it cuts a dado that is roughly 3/8" wide with an angled bottom. I don't think that is supposed to be all that there is to it, but I'm not coming up with anything.

There are no visible spring lines, so I think it's supposed to run vertically.

Any ideas?

[Roy Lindberry]

And here is one more picture, in case it helps.

[John-Paul Volkenant]

Purely a guess —I don't have any experience with molding or joinery planes— but could it be for sliding dovetails used in casework?

[Roy Lindberry]

Purely a guess —I don't have any experience with molding or joinery planes— but could it be for sliding dovetails used in casework?


Wow, that's a good guess. It could be. I would have to run it one way and then the other way, but it would have to be tilted. And it would make sense to have a knicker as well.

I'll see what other answers come in, but that actually looks like a good idea.


***added in edit***

Thinking further on this, I don't think that will work. If the plane is used vertically, you get a straight side and a beveled bottom (not flat), but if it is used at an angle, you can get a flat bottom, but it still will not angle the side as a sliding dovetail would need to be. Because regardless of the angle, the iron still cuts straight downward.

The only other option I could think of would be if there was an angled jig to plane against that would allow you to plane downward at the desired angle. But like I said, I'm at a loss, so any guesses are better than what I have so far.

[Larry Williams]

It looks like a user modified dado plane to me. The intent was most likely an angled dado. The missing nicker and wedge suggest mixed success. The lack of a depth stop puzzles me so I've not sure of this.

[David Keller NC]

Larry's probably right - it was likely user-modified for a special purpose. However, I've seen pairs of planes before that look like this that were designed to create interlocking, dust-proof joints.

[Gary Roberts]

This one looks suspiciously like a plane used to create part of the weather tight joint in a window sash. That is if my brain is working at 2 in the morning. The knicker would be used to handle the end grain met at the ends of the sash. No depth stop was needed as the depth of the cut was self limiting by the inherent fence.

I think?
Gary