While tidying some junk boxes I came across a stash of perforated brass
disks used to label keys.  Unless I intend to open a prison (hmm, the
grandkids *do* need a place to play), the supply was far more than I'll
ever use.  So, I decided to make an adjustable clamp spacer per the
design one sees occasionally in "Model Engineer".

The disks are stacked on a threaded rod which is countersunk and
soldered into the bottomost disk.  A knurled thumbscrew on the top
allows tensioning the stack.  In use, one merely swings aside the
unneeded disks such that the remaining 'stack' is the proper height for
the clamp.