noun
ultra-fine rasp; ultra-fine file
A very fine-toothed file or rasp used for delicate finishing work in metalworking, woodworking, or similar crafts.
仕上げには油目鑢を使うと表面が滑らかになる。
Using an ultra-fine file for finishing makes the surface smooth.
General term for a file or rasp; 油目鑢 specifies an ultra-fine grade.
Compound of 油目 (あぶらめ, 'oil grain' or 'fine texture') and 鑢 (やすり, 'file'). The exact derivation is uncertain, but the name likely refers to the very fine, smooth finish it produces.