[Shop-talk] Specialty bolts

[Steve Hammatt, Mount Vernon WA USA]

Ibm looking (so far without success) for a type of bolt that:
1.  slight convex head
2.  underside of head has 4 facets (sides) that taper inward.
The bolt is designed to fit into a small casting with a matching
4-sided tapered hole to lock bolt from rotating while being
tightened.

Anyone ever seen anything like this?

Steve Hammatt
Mount Vernon WA USA