Another bearing block design for Thomson Super 8 linear bearing (1/2")

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