Mystery bronze grooving plane

[Eric Brown]

This plane has me baffled. Perhaps one of you will recognize it and tell me exactly what it is used for. It has a runner on the bottom 2mm thick by 11mm high. There are no spurs or fences. Only the cutter. The cutter is made in a "T" shape and sharpened with a round file/stone. The cutter is 5mm at it's widest and 3mm at it's narrowest. The cutters "T" is 1mm thick. It appears that a groove about 2mm would first be cut in the board, followed by this plane. I suppose that repositioning the blade would allow a deeper "T" to be cut. Thanks for all responses. Added picture of how it cuts wood (one pass after slot cut). 281354281355281356281357281358281359281368

[Jim Koepke]

This looks like something a pattern maker might create.

Have you put it to wood?

jtk

[Jim Koepke]

That looks like it may have been an early way to make a "Tee" track.

It is surely a mystery when it comes to original intent.

jtk

[Steve Rozmiarek]

Isn't some old weather stripping meant to be installed in a slot like that? Home brew weatherstripping planes can be pretty wild, I'd guess that.

[Rob Luter]

I'll second the weatherstrip opinion. T-Slots continue to be used today. Typically the groove isn't that deep though and the "T" section is at the bottom of the groove. Is there any evidence of a depth control mechanism?

[Eric Brown]

The only adjustment is with the cutter itself. It can be positioned anywhere from the top to the bottom of the runner. If positioned at the bottom of the runner, the Tee would be from 9mm to 10mm deep. This seems deep to me for a weather strip, but I really don't know. I'm open to all suggestions. Thanks. Eric