bought a couple tool boxes

[4435]

And someone tell what these are/for? Looks to me they would clamp on the edge of a surface plate.
Tom

 

[Eric in IL]

They are a set of trammel points. They usually clamp to a machinist scale of the needed length.

 

[Eric in IL]

For layout of larger arcs or circles.

 

[JD Seller]

Eric has what they are. They are clamped to the block as a storage case.

 

[Spook]

Beam trammels. Clamps to a rod. For circles or circle segments.

 

[Moonlite37]

look much nicer than what I made.