Granite top table, 4 sides, 3 legs, 2 cup holders?

Ok it was born as a machinist’s surface plate, for making precision height measurements. I bought it used, pretty cheap, because the design of the steel stand impressed me, something like an MCM table. Not sure what the two “cup holders” did but maybe the folKs at the machinist club meeting tonite will know. We made a plywood cover to protect the precise granite surface and let us use it as a regular table when not measuring things. It has a lot of female-threaded stainless steel fittings on top where various instruments could be held in place. I think it was used by computer-controlled machines to check their work but still researching it. The stand has three pads on it at certain points which support the granite. All surface plates use three support points. My plate is well beyond it’s calibration date but it’ll be fine for the work I do. Granite plate measures 39.5 x 42 x 6.5”. Anyone know the real reason for the cup holders?

 

Containers for small parts, removable so you didn't have to crawl under to refill, just to take out the cup & return it?

 

A place for your beer?

 

Must mean something that they are at center & right, not both centered, like pedals in a car.

 

No one at the machinist club meeting was familiar with that type of surface plate, and I think Bron got it. You need thumbscrews to hold the measuring instruments to the threaded holes, so it is safe to say there were circular containers which held said thumbscrews.