It actually lapped the surface plate it is sitting on which came from the same source. The surface plate was purchased surplus from Allison transmissions if I were to guess where he got it and the lapping plate was probably there to flatten chucks and mounting plates for lathes (which I still use it for to this day). It is great to use something he used and to have it work so well. I know not many people here will get real excited about a lapping system, but I would LOVE to see how this compares to using a 325 DLP and a Shapton DGLP. I'm in the Indianapolis area, so I imagine Lynn would be the closest member with access to these systems. I'll have to think about having some sort of super nerdy hone flattening get together here in the future .