*3725 does not include rotary table. Image shown is 3725 mounted on an 8730 rotary table, which is not included. The Sherline tooling plate is designed to fi t the P/N 3700, 3700-CNC, 8730 or 8700 Sherline 4" rotary table. It is just under 5-1/2" in diameter and made from 6061-T6 aircraft grade aluminum. It has a pre-drilled and tapped pattern of 10-32 holes to facilitate mounting of fixtures to its surface. The holes are on 1" centers except for the outermost holes. You can also drill and tap addition holes as your job requires. Tooling plates are intended to be a sacrifical fixture and are simply replaced when they get too many holes in them after being used for numerous jobs. In order to help protect the surface of your rotary table from mounting screws that are too long, the pre-drilled holes in the plate are not tapped all the way through. If you tighten a mounting screw and it begins to bind, the screw is too long, and you should remove it and find a screw of the correct length. The tooling plate has a raised area on the bottom that registers in the hole in the center of the rotary table to help you center the plate. The plate also has four countersunk holes for 10-32 x 1/2" mounting screws (included) and comes with four T-nuts that fit in the T-slots of the rotary table. If you align the T-nuts with the outermost reference groove in the top surface of the rotary table, the T-nuts should align with the mounting holes. Do not overtighten the mounting screws or damage to the T-slots and surface of the rotary table can occur.