I made this thing for the excelent Ultimaker quiet retraction by Maxy : http://www.thingiverse.com/thing:53690 It's a very good upgrade, very usefull, but with the weight of the nema 17, the upgrade became brittel and I didn't want to print an another on. So I imagine this thing. It add again some noise but less than the wooden backplane... I also add a fan holder on it for the nema17... I printed it with Layer height 0.15 / Shell thickness 1.2 / Density 100... and fixed with 2 M3 1.6 mm in the wood and 1 M3 2mm to fixe on the nema17...