T-Slot for 1/4-20 Carriage Bolts and hold down clamp

T-slot for my MP CNC. It works with standard carriage bolts. This works well and prints in 8" lengths. It's a good test on how well your printer is fusing each layer. Don't over tighten or you'll print a few more!

Probably can get 5 to print at a time on a Replicator bed.

One T-slot has flat sides, the other has small edge to bite into a foam spoil board.

Works with http://www.thingiverse.com/thing:21057

Added: Two others added with no center hole. Could be parametric.