Smallest clamp possible?

[Franko]

I find these small Cieco clamps are often useful. They open a little over 1/2".

 

[Desolus]

I really need more information about what you are trying to do before I can offer a solution.

 

[David S]

The OP seems to have abandoned us.

David

 

[KBeitz]

I use what Franko uses. It come with an install handle.

 

[yendor]

But then there is always the concept that we all have (some level) of machinsts skills here - and you could always make something.