Using a Sinclair insert style bullet comparator?

[canoetrpr]

Obviously there has got to be a simple answer to this as there were no instructions in the package. The inserts seem to be held by a teeny tiny screw like thing. It wasn't screwed into the comparator so I put it but it doesn't take a hex key or anything like that.

Does not seem like it has something to hold on to to tighten or loosen. Anyone have any idea of how this is supposed to work?

 

[joe-nwt]

The small screw holds the various inserts into the comparator body. The thumbscrew attaches the comparator to your calipers.

[youtube]3wlsgGKfjfI[/youtube]

 

[canoetrpr]

I tried a hex key for the small screw and it seems to work to tighten it up. My eyes must be getting bad as it didn't seem like it would accept a hex key... it does.