This is a very cool center finder invented by http://www.thingiverse.com/hlyman. I rank this as one of the most interesting and useful things on the thingiverse. Certainly the backstory is the most compelling.I scaled it to 75% to fit the replicator bed. I also redesigned the pins to make them a press fit, thus eliminating the need for screws on those parts. I also redesigned the rotating brackets and control knobs to improve their operation after scaling. I put multiple parts in one file to speed up printing.NOTE: Scale the Right Arm file using inches->mm button or download the last file on the list which has the scale fixed already.Print each set of parts and assemble according to the final picture. The pins are press fit into the donut looking part. The ribbed nature of 3D extrusion parts makes these parts quite hard to get apart. This allows them to act as a screwless fastner. Make sure the mating surfaces of the base and "right" arms are smooth so the mechanism can slide easily under rubber band power.Press control knobs thru the long sides of 4 Arm base so that tab presses into the slots on the "right arm" jaw. Note the right arm jaws are oriented with one of them with its flat back against the flat back of the 4 Arm base. Then the other "right" arm jaw goes on last with the protrusion facing the back of the 4 arm base. The rotating brackets are fastened with #3-1/4" slotted flat head wood screw - http://www.boltdepot.com/Product-Details.aspx?product=7774. Make sure screw will thread without cracking plastic. Don't tighten too much as brackets need to rotate.I set the bed temp to 110C to prevent parts from lifting and warping.I will be adding more details over the next few weeks.