Sighting Disk for accurately locating grid points

Instructions

Make a grid; any grid. Import design and place center at 0/0. Suggest the 1/8” bit that comes with Origin at speed 5. First cut hole in center, 1/8” or 3mm or something like it. (I then cut a larger 1/4” / 6mm larger hole halfway through as I thought that would help visibility;, it did not, don’t do it.) Then cut the outside profile. The finger holes are valuable, I don’t see any value in cross hairs myself. 48.2mm is a little loose. 48.4 might work but might need sanding. I’ll try 48.3 when I make another one. EDIT: I have added a 'Slotdisk', a 48.4mm version with slots instead of a hole. The idea being that it may be possible to use this without removing the spindle by sighting it from in front and then from the side.