On 3/29/2014 11:01 AM, Jon Elson wrote: > On 03/29/2014 03:39 AM, Jeshua Lacock wrote: >> >> >> My 1080 pound 4x5 foot granite surface has a glass cut looking surface that >> I bought surplus. >> Anyways, do you think the reason it is shiny is because it is grade A, while >> the grade B should be matte? >> >> > It is most likely an optical bench, made to be extremely > stable and free > of vibration, and probably had air bellows supporting it. > It is probably > NOT a surface plate, ie. one that is ground with diamond > paste to > be flat to within some insane tolerance for inspection purposes. > The fact it has a mirror finish means it was polished, not > lapped > against other plates, in the time-honored 3-plate method of > automatic generation of flats. > > Jon > > urceforge.net/lists/listinfo/emc-users
Jon, Are you familiar with Optical benches/tables? I bought a 5'x8' ground cast iron optical table that is supported by air bellows although a couple of them are missing. It was made in three sections and then pinned together. It has a few small holes in it that were used to attach things to it. But it has barely been used. I was thinking of using it as a setup table for weldments, but it is almost too nice for that. Dave ------------------------------------------------------------------------------ _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
