Help with mill bit identification

[Canus]

Need help identifying two mill bits. The first looks similar to a woodruff seat cutter. The second appears to be a countersink bit but the corkscrew flute pattern is unusual. Not sure what type holder would be used with the second bit.

 

[JimDawson]

I think the top one is a T-slot cutter.

Looks like a countersink to me. Back in the ''old days'' some of the cutters screwed in to the holder. I've never actually seen the screw in holders. Kind of looks like a Whitworth thread with the round bottoms.

 

[Canus]

Thanks Jim for the info. I agree about the T-slot cutter. Made a holder yesterday for the countersink bits. Have several with odd angles (78, 86, 100 degrees).