About this 3D model

Update 11/9/14: My best design for the Super 8 is this one: http://www.thingiverse.com/thing:534210 or this one: http://www.thingiverse.com/thing:540629 They have screws to allow precise adjustment of fitment- no more cable ties! Update: this block isn't very good- the lack of preload (fitment) adjustment makes it a little too loosey-goosey. Use this one instead: http://www.thingiverse.com/thing:134561 It works better. This block provides no fitment adjustment- it just lets the races float. Hole spacing has changed from the previous version- they are now 15mm apart. The flat surface of the block is 19.05mm (3/4") from the axis of the guide rail, same as the previous version.