What kind of plane is this?

[Eurekan]

A buddy just bought this plane along with some other stuff and I guess he bought it cause he'd never seen anything like it. Me either, never seen anything with a throat that large . Can someone identify this and what its used for? [attachment=21817]

[Strokes77]

Butt mortise plane.

[Bill_Houghton]

Butt mortise plane.

Yep.  Butt (hinge) mortise plane, used for the wide, shallow "mortises" (technically, since they're open on one side, rabbets) that butt hinges on doors fit into.  They were developed for architectural hinges, I think, but could probably be used for hinges on large cabinets, too.

If you do some door hanging, I think they're a great tool.

I will wander from your original question to comment that the mortise for a butt hinge is not just a decorative feature.  It transfers the weight of the door through the hinge to the jamb or the door itself, so that the screws need only keep the hinge in place, rather than carrying all the vertical weight of the door.

Some discussion of use here: https://www.finewoodworking.com/forum/us...tise-plane
Or, my discussion of how I use the one I made for myself: http://www.woodcentral.com/articles/hand..._114.shtml

[WJB]

Rumbold patent.
For hinge mortises (repeated to hit 17 characters)

[AHill]

More info on how to use a butt mortise plane (Lie-Nielsen makes a more modern version):

https://www.youtube.com/watch?v=ctKNbMOpcXo

[DCarr10760]

Yeah, Butt Mortise plane it is, it's more of a special purpose router plane, than a bench plane.  It's length makes it easy to register it on the door edge.

~DC

[Eurekan]

Thanks to all for answers. Now I'm jealous. He got it so cheap and it looks in decent shape. Used and new prices are insane.

Again, thanks to all.

[Bill_Houghton]

Thanks to all for answers. Now I'm jealous. He got it so cheap and it looks in decent shape. Used and new prices are insane.

Again, thanks to all.

As I commented in the post I linked, you can make your own pretty cheap.

[AHill]

For what it does, a router plane is much cheaper and more versatile.

[Bill_Houghton]

I looked up the Rumbold patent on which which this plane is based (here, from Datamp), and, to my surprise, it dates from 1951.  I hadn't realized it was that late, and it explains why there's no Stanley version.  By 1951, Stanley had discontinued or was discontinuing much of their plane line, including, back in 1934, their No. 171 door trim and router plane.

I find it interesting that it took that long to develop this idea.  I personally find it a very quick, reliable way to make hinge and strike plate mortises.