Welcome to ModelEngineMaker !If you have problems registering or logging in, please use the contact menu option to request assistance.
The slots are precisely cut in a grid fashion. The area of the vacuum is sealed off by tubular rubber gasket material inserted in the slots, and there are 9 threaded holes over the table to introduce the vacuum inside the "roped off" area(s). You only need one hole open in an area, and all the rest are closed off with screws.The holding area can be fairly small, but the holding force is 14psi over the roped off area, so the best usage is wide and thin material, just the type that's hard to hold in a vise.I'll post a photo of the top of the plate tomorrow.