I had a project requiring me to hold some small parts. I thought of vacuum, double sided tape and hot glue and discarded each for one or another reason. The parts had a hole through them. The solution I came up with was nylon bolts. I threaded the parts 1/4 x 20, bolted them from the back and, like magic, they stayed as they were and I machined through the fasteners as well. Oh, on the second run I figured out if I put washers under the bolts I could use then more times before they become 'too short'
Ron