Master Palm® Pneumatic. Industrial Micro Stone Mini Low Profile Right Angle Disc Die Grinder, 16500 Rpm with 1/4" mandrel. Use Die Grinder As A Sander Master Palm right angle micro stone die grinder can be used as a sander when it is connected with a roloc holder for twist-lock discs. No. 38050 is a specialty pneumatic air die grinder tool that is also designed as a sander for refining grinding, sanding and polishing. This die grinder tool equipped with a m6 diameter male shaft can fit m6 scr..