Small engineers vice,
For holding small things VERY firmly !!

If you have never used these, then you will be amazed at the gripping force.

The photo is of a prototype I made from Acrylic.

print it out, if you are brave, push M3 nut in as it just crowns the top of the nut hole. ** do not use support material if you do this !!

Fit the two M3 nuts, and the two bolts,

The one in the middle goes through,
the one on the outside, acts like a see-saw, providing the grip.

Note try to keep the faces parallel when clamping.

Enjoy

Ceri.