Printed a hand at 200% to use as a 'demo hand' for the Orlando Maker Faire. The demo hand that I've been using was based on the Raptor Reloaded, which had the problem that the elastic at that scale created so much force that most people couldn't close the hand. And then it was in a car crash, which meant I really had to print a new demo hand.
The Osprey works fantastically well as a demo hand, because the push/pull mechanism is very easy for people to work. Also, the small gauntlet with straps is easy to adjust to a wide range of arm sizes.
- 1.75mm Bridge Nylon for the tendons. It's a little soft, but 3mm filament doesn't fit in the finger channels.
- 1.5 inch velcro strips (double-sided) work great. Turned so the 'soft' side is towards skin.
- 4 #12 1.5in metal screws to hold the velcro strips to the gauntlet. I printed some caps to screw onto the ends of the screws. I could have used shorter screws, but I couldn't find any that were that large. So instead I printed caps to cover the pointy ends, which actually look kinda cool (IMO).
- 10 socket head set screws ¼-28 x ¼. That is, quarter inch diameter set screws fit into the holes with just a little force, to hold the tendons in the gauntlet in place.
- 12 #6 x ½in wood screws through the 'template' then through the velcro, into the bottom of the palm. The template helps hold the velcro in place, so it doesn't pull on the screws so much.
Printed the palm, fingertips and gauntlet in T-Glase, and the pins and proximals using PLA, as it's a bit softer than T-Glase. I printed the 'D' size, which was quite tight, but with some encouragement (rubber mallet, pliers) everything fit into place, and there's no wiggling.
The cap for the #12 screw is http://www.thingiverse.com/thing:1003517 .
So now, I think we're all set for the Orlando Maker Faire next weekend. Hope to see you there!