A dust shoe for Proxxon rotatory tool use as spindle for CNC machine. Pictured is a Shapeoko CNC. Using a 20mm motor mount, usually refer as (ID20mm Spindle Motor Mount Proxxon IB/E 50/E) Checkout the new version, http://www.thingiverse.com/thing:724287, the new version does away with the screw mounts, these where a pain to remove every time I wanted to replace the endmill/tool. The new version uses a easy to mount-remove bungee cords. New version also provides better clearance for clamps or other hold-down tools. This version require way too much clearance.The threaded coupler is kind of tight, clean thread well after printing and work the thread after a while it will just work well and there won't be any air gaps. Note: important rotate 180 deg coupler, base (not body) and and spindle mount before printing (print these parts up-side down for best results).