I've been meaning to make this for some time. Now I need it, so time is up. My RT platten is 6" so I made it a bit bigger at 7". I was thinking I could go bigger yet & get added utility on my lathe face plate, but I start to run into other obstacles on the RT so call it good at 7" & see how this turns out first. Mostly my intended projects are small so I came up with a 0.5" grid of 8-32 tapped holes, retained with four 1/4-20 hold down bolts.