Terminal device bolts, Otto Bock norm, 1/2-20 UNF thread

The standard Otto Bock wrist uses a sub-16.000mm cylindrical bolt. Our own wrist units adapt to that. The V2P - as well as other US-American terminal devices - ships with a 1/2-20 UNF threaded bolt.

What to do?

1. Otto Bock bolt adapter

This part costs 80 CHF. It is manufactured roughly precise but not overly exact. So I believe it is overpaid.

2. Cut your own adapter

I found a thread cutter (80 CHF) and an aluminum tube (3 CHF).

The aluminum tube is comfortably purchased at 15,5mm diameter as our wrist mount adapter is flexible to also allow for Otto Bock's "16mm" bolts.

The thread cutter is a real beauty. It works well, I can use it single handedly.

So after cutting a thread into the aluminum tube, the terminal device (here: V2P) is screwed onto the tube end.

Then the tube is sawed off carefully.

This is the wrist adapter - view in situ onto the V2P Prehensor.

This is the result: a perfect fit onto my wrist (here: MSM 0.2 prototype).

Cite this article:
Wolf Schweitzer: Technical Below Elbow Amputee Issues - Terminal device bolts, Otto Bock norm, 1/2-20 UNF thread; published 22/12/2009, 20:11; URL: https://www.swisswuff.ch/tech/?p=247.

BibTeX: @MISC{schweitzer_wolf_1603483197, author = {Wolf Schweitzer}, title = {{Technical Below Elbow Amputee Issues - Terminal device bolts, Otto Bock norm, 1/2-20 UNF thread}}, month = {December},year = {2009}, url = {https://www.swisswuff.ch/tech/?p=247}}