Sanding helper for SEM sample cross section

This is a sanding helper to prepare SEM cross section samples. For SEM cross section sample preparation, samples are embedded in epoxy, sanded and polished until achieving a smooth surface. However if you need to reach a precise section on the sample it is difficult to stop the polishing at the right time. This system includes small molds to cast the epoxy and holders to maintain the sample during polishing. The holders have ball bearings to roll on the sand paper and stop the sanding when a specific position has been reached. There is also a base with a micrometer to precisely control the position of the sample in the holder and set how much material you will sand away. There are two holders, one with fix bearing rollers for manual sanding with a back and forth movement, and one with mobile bearings rollers to use on polishing wheels. The fix bearing holder requires 3X 3*8*4 (ID*OD*T) bearings and M3 nuts and screws. The mobile bearings rollers requires 3X 3*8*4 bearings, 3X 3*10*4 fl