When I need thinner shims I cut the thickness of the strip by mill. Shown is 2mm thick shim.
3mm以下の敷き板が必要な時はフライス盤で削って必要な厚さにしています。これは2mmの敷き板。
I made shims of various thicknesses from my metal sheet off-cuts and marked thickness on them by number punches. Bottom one is from annealed beer can. Thickness is about 0.1mm.