Spoil Bed Holder for Sainsmart 3018-pro cnc router

This is a spoil bed holder for a bolt pattern centered 20mm past the end of the bed. 

Re-uses the M6x45 hex bolts from the garbage Genmitsu work holders that came with my 3018-pro kit (https://www.sainsmart.com/collections/genmitsu-cnc/products/sainsmart-genmitsu-cnc-router-3018-pro-diy-kit).

These holders position the bolt centered 20mm past the end of the 180mm (actually 179.5mm) tall bed. The holder is 14.9mm tall (slightly less tall than the aluminum table to ensure clamping). Approximately 9.9mm of the bolt thread will be in the holder. Depending on the thickness of the spoil-board, you might want different bolt lengths. These bolts are 20mm outside the aluminum gantry surface, so that they will not interfere with cutting. The wing-nuts that came with my Genmitsu work holders (clamps) have a 23 mm width, so these will also be outside the work area.

Assuming a ½" (12.5mm) thick spoil board, the bolts should be at least 25mm thread length (1"). The default M6x45 bolts are 45 mm long, so they will protrude upwards from the spoilboard. The wing nut and washer are 5 mm thick together, so ensure that your M6 bolts are at least M6x30.

The spoilboard should be 60 mm (6 cm) longer along the y-axis to match the spoilboard holders plus table (180mm + 60 mm = 240mm). The holders are meant to be printed on edge, with the teardrop point facing upwards (eliminates overhang in the bolt-hole).