APS Rupes Washer Mod is a specially shaped washer for the large Rupes eccentric polisher base mount (usually from 12mm stroke) and is used to modify the distance between the top of the support plate and the rubber lip of the eccentric gear sleeve located above it.

The Rupes eccentric polishing machines Rupes LHR12, Rupes LHR15 series, Rupes LHR21 series (including Mark III) have a rubber lip on the lower edge of the eccentric shaft or eccentric gear housing. This rubber lip is often in close contact with the Velcro plate and prevents it from rotating freely. This fact now leads to the fact that the dual-action effect, which is composed of the eccentric and rotary support plate movement, is severely impaired, especially with higher print run pressure. At the same time, the rubber lip rubs against the top of the Velcro plate and not only rubs against the sticker, but also creates abrasion, which shows up in unsightly traces of abrasion.

APS Washer Mod washer increases the distance between the backing pad and the rubber lip by 1-2mm, thus enabling higher free rotation and better material removal rates.