Metal Trautman Hook · 31 March 06 by Jesse Crossen
We sent the Trautman Hook design off to ProMetal and the printed metal parts arrived yesterday. Today, we got finishing tools (screws, drill bits, a tap, and a die) from McMaster-Carr and put the device together. Here are some pictures of the parts when we got them:
As you can see in the closeup, the printed surface is a bit grainy, but not unattractive, and vibratory tumbling would help it look smoother. After a little drilling and threading, it went together without a hitch. Here’s the assembled device:
The action is smooth and the backlock is tight, the only issue is that the grippers don’t line up perfectly, probably due to the fingers warping a little during heat treatment. The total error is about 0.050 inches.
The next step is to test it with a body-powered harness, then we’ll try to break it to see where it needs to be stronger. Also, we’re already planning on making a few revisions that would make the device more durable. The cost of this prototype was $500 (ProMetal’s minimum order) plus about $50 for finishing tools. Thanks to Kenneth Heide, CPO for funding it.
