Hi there, I am attempting to prototype a 3D board game with magnetic pieces. The board is essentially a bevelled cube with tiles on the surface and edges + corners. I need three different types of tiles to glue or fit firmly into the board skeleton. Here is a sketch of project: To create tile (A) it must fit into the following measurement where the Tolerance of the machining process is (0.005") or (0.126mm) What is the correct way to account for this tolerance in making a CAD file? do I take T/2 away from every edge and redraw the outline ? (T=Tolerance) Here is an image of the hole that Tile (A) must fit into: Please explain how to correctly draft the tile dimensions.

Here is a diagram of what I understand I must do to account for a tolerance number. The red line is T/2 distance from the edge. Is this correct ? I am not confident about this calculation. Please Advise.