Keyway Cutter Unknown

[BROCKWOOD]

Just trying to identify an item that I received in a lot that I bought. It's a keyway cutter - but the crossectional shape of it baffles me.

CONANT BROACH CO. 44826 WN
TN-18454
TS 3819
M2 H.S.S. LEFT HAND

Sorry for the bad pics. Ain't been no sunshine since October.

 

[chips&more]

Looks like a vise hold down. But you should have two of them.

 

[BROCKWOOD]

Looks like a vise hold down. But you should have two of them.

I wish I knew what you mean by 'vise hold down'. I can see making an obnoxiously shaped guide - but why? I must be better off finding the usual key cutters.

 

[benmychree]

Probably fits some keyseating machine.

 

[P. Waller]

May be a surface broach, they are made to fit different machines with particular mounting requirements.

Do not be constrained by the commonly known methods such as a bushing in a hole that the tool passes through to form an internal key seat or a simple round hole that will accept a polygonal broach that produces any number of sides and shapes. Surface broaching is fairly common in manufacturing.
https://www.mhi-machinetool.com/en/products/detail/broach.html