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Surface Plates & Supports

600_2precision-products-product-rock-of-ages.jpgWe manufacture a full range of standard surface plates.  We can provide large plates for special applications up to 50 feet in length and weighing up to 200 tons.  For surface plate use we offer American Black, Barre Gray Granite, and Salisbury Pink, all from our own quarries in North America.  We also offer Impala and Zimbabwe Black as import alternatives.  Barre Gray has been the industry standard for durability in inspection plate use for more than 60 years. Salisbury Pink is the hardest and most durable granite currently available for surface plate use, even harder than our Barre Gray.  Although not as durable as Barre Gray or Salisbury Pink, American Black is an appropriate material for special customer requests.

If the working surface of your surface plate requires mounting points we can install stainless steel threaded inserts in ANSI NC or NF, or ISO Metric Standard thread sizes, precision dovetail slots machined into the surface of the plate, or steel T-slots set into the surface of the plate.


In accordance to GGG-P-463c, Rock of Ages insures accurate readings of surface plates by supporting the plate properly on three support points.  Three points are preferred and are located 1/5 the length and width from the ends and sides. Three supports are used because it is the only way to consistently support a surface plate object without the weight shifting from one leg to another.  Any attempt to use more than 3 points may cause the plate to receive its support on various combinations of three points and the plate will settle differently and possibly deflect out of tolerance.

Rock of Ages provides various options for supporting surface plates:

  • stationary stands with leveling screws
  • stands with casters
  • stands with casters and leveling screws

All models with casters come with wheel locks as standard. Any working height can be specified to meet your application need.

Surface Plate Stands

Our surface plate stands are engineered and specially designed to provide rigid support for your surface plate.  Being constructed from welded structural steel, these heavy duty stands guarantee surface plate accuracy.  No assembly required. Stationary stands have leveling screws at the bottom of each leg.  Stands with casters are furnished with two fixed and two swivel casters for easy movement. Standard colors are grey or black but stands can be supplied with any color paint or powder coating with an additional charge.  

Support Systems

Designed for large surface plates that require precision leveling: The three-piece design removes the need for oversized, heavy and expensive steel support stands.  Three 12” x 12” (sometimes larger as may be required) granite blocks and three wedge levelers are used to support your large surface plate.  This system allows flexibility in locating supports to suit your application. The wedge leveler provides precision height adjustment for accurate leveling. Large supporting surface ensures solidity and rigidity. Granite blocks are cut to length to provide the desired work height. Different models of heavy-duty wedge levelers are available depending on your surface plate needs.

Quality & accuracy

Feel confident in your decision to use Rock of Ages knowing our surface plates meet or exceed Federal Specification GGG-P-463c and that all standard metrology products are supplied with a NIST traceable calibration certificate with your purchase, at no additional cost.