I think I remember that there is a kind of "touch indicating paper".
If you are uncertain whether two surfaces touch when an assembly is
assembled, you can put some of this paper on one of the surfaces,
assemble the assembly, disassemble it, and if the touch-indicating
paper has changed colour, you know that the two surfaces did touch.
What is this kind of paper called, where can I get it, and does it
only work for metal surfaces, or does it also work for wooden
For woodworking and similar jobs I use a suitably sized blob of blutac
sometime with a little sellotape over the blob to stop it sticking to an
unwanted surface. it has the advantage of also telling you the amount of
clearance by measuring the thickness of the squashed blob.
Would that help?