The mounting platform bolt pattern will vary, based on the machine on which it is installed. The bolt pattern consists of 4 equally spaced threaded holes. The threaded holes are 3/4-10 UNC-2B X 1" (25 mm) deep.
For ST-20L through ST-35L models (including Y-axis variants), the pattern is 10.938" (277.8 mm) X 3.25" (82.55 mm)
For ST-40 through ST-55 models (including long-bed variants), the pattern is 14.625" (371.47 mm) X 3.25" (82.55 mm)
* Exact details can be found on the Machine Layout Drawings for each machine.