Summary

Believe it or not, this is a modification of https://www.thingiverse.com/thing:3273934. I made 3 basic modifications: the first was to add more ridges, the second was to change the overall shape to a more rounded one, and the third was to do a double-twist to the new shape. This blog page explains how the double twist works: http://birkbinnard.com/blog/do-the-twist2/.

This part printed in slightly more than 22 1/2 hours using a layer height of 0.200 mm and a print speed of 80 mm/sec.