Zheng Penny Mortar Fat Nock
by AMS3000, published
I had trouble printing the nock part of the very cool zheng3 Penny Mortar, so I popped it into Tinkercad and fattened up the walls in the trouble area (the hole where the band goes through).
Print and use in the place of the normal nock on the Penny Mortar ( http://www.thingiverse.com/thing:24556 ) if you have trouble printing it like I did. Slic3r just kept leaving gaps on the walls of the hole in the original nock, and the part split in two.
I printed it on my Printrbot with 3 perimeters and 40% infill.