Hi frugalolegeezer,

Thanks. The black granite slabs are surface plates available from MSC ( https://www.mscdirect.com/product/details/00150011 ) and other tool distributors such as Grizzly. I have a Grade B surface plate of 12" x 18" x 3" and has an overall unilateral flatness tolerance of 0.0001". It weights around 80 lbs and I would prefer the next larger size of 18" x 24" x 3" but it weighs around 150 lbs. In the case of the smaller import surface plates, the shipping costs can sometimes cost more than the surface plates. I bought mine years ago from ENCO (now part of MSC) for less than $50 and when they had a special offered for free shipping.

I have a project planned in 2017 to make adjustable three point leveling pads epoxied to the surface plate bottom.

Paul