check out my other things;http://www.thingiverse.com/Mattsedgley/designs An adjustable y-carrige tensioner, for prusia i3 derivatives. Printed on my custom i3 derived 3D printer. Use 40% infill.. both designs use the same foot print as my LM8UU holderhttp://www.thingiverse.com/thing:206956 26x16mm all holes, designed for M3 cap head screws, holes will need to be run through with a 3mm drill i expect. Tensioner part should be fixed to underside of bed, floating part, is exactly that, it should float (it does have 4 mounting holes, as you could cut grooves in the underside of your bedfor this part to slide in, which would help keep the linear movement. the floating part requires an m3 nyloc, being forced into one of the holes, it will be very tight, this is deliberate, a punch, and a hammer may be required, the the Fixed part contains an M3 which pulls the two parts together, you can choose your own length of this! The belt clamp again will need holes opening out to 3mm, You'll then need an M3 tap, to tap the holes through both the floating part, and the fixed one, again there are two options of where to attach the belt.