Thanks for the advice, vacuum chamber sounds great, but I won’t be able to get to one any time soon.
As for this one in the photos, it’s actually made from 2 pieces glued together and then sanded and just oiled a bit for the look of it. It was just a test piece to see if the woodworking glue would be strong enough for actual use of the tool.
The tool itself won’t be used in water, maybe a bit damp sometimes, but in general never, so that shouldn’t be a problem. I am more concerned with making it strong enough so it doesn’t split.
I’m not sure if I can make it only from wood, maybe some metal for reinforcement? Like soldering the Allen wrench to a small metal plate that would then be inserted between the 2 wood pieces and then rivet everything together? Or is it better to stay at 1 single wooden piece and just nail the wrench in it or with a drilled hole and a bit of carving and then adding epoxy to the inside?