I wanted a durable, but fairly flexible mount for a Bondtech extruder (specifically for the Rigidbot - 3/4" square tubing) so I designed this one and printed it in Taulman Nylon 618. For the two holes, I bought and inserted some small magnets to help hold onto the frame and then closed them off with M5 brass inserts - which actually screw to the original clamp that came with the Bondtech. I've actually been very impressed with how well this mount has worked.

Brass Inserts: http://www.mcmaster.com/#94180a361/=10zehil

Magnets: https://www.kjmagnetics.com/proddetail.asp?prod=D46-N52