I modified the Mark's threadless ball screw in order to attach the bed directly. The slope angle is 38.5 deg. The center distance is 9 mm.(this is same with my lm8uu holder) The hole distance of flange is 31 mm. Thickness was reduced to 12 mm. I did not test yet. I'd like to use this as X-axis and Y-axis on my printer. I hope there's a good result. August 5,2013 -- uploaded 20130802_threadless_38p5.stl The hole dimensions for 623 bearings were reduced from 3.4 mm to 3.2 mm. August 8,2013 -- Added Youtube movie http://youtu.be/TxOifzvnm70 (tested by hand) September 9, 2013 -- uploaded Inventor original source file "20130802_threadless_38p5.ipt"623zz bearing -- 3 EA M3x10 mm bolt -- 6 EA M3 washer -- 5 EA M3 nut -- 6 EA