Hi om,

My best guess would be industrial/production broaching inserts.

These are some spares I had when I did real work.

David

Yes they sit on top of the insert and the clamp holds them in place. You adjust the top plate nearer or further from the cutting edge, to get best chip break, which were flat triangular tips with about a 1.5 to 3mm tip radius negative rake and no front clearance except for tip angle so you can use both sides of tip 6 cutting edges. I could take 0.250" cut feed about 0. 050" at 3000 rpm Roughing out. The chips fly and the tool got hot evan with coolant.

David

They're chip breakers, depending on the material and depth of cut they were positioned close or away from the cutting edge using the racks. I can remember when they were state of the art but nobody really knew how to use them to the best advantage as the lathes had speed ranges of 1000 rpm tops as they were designed for HSS