via Planet Geek!

So what do you do on a Saturday afternoon when your 3 year old decides its time to sit down and play for a while. Hmm. Tinkertoys. We haven't played with these much. Well, gee. These things sort of rotate around an axle... and... if you assemble these, you get a tripod... which can be anchored here... aaand... Huh! One of the tricks was coming up with a suitable counterweight arrangement. The original design used the big 'cue ball' sized Tinkertoy pieces arranged in a sort of cluster. That didn't quite provide enough weight, so I snagged a spare exercise weight we had lying around, and loaded it up. The counterweight is about 8lbs or so, and works great. The next was building a decent sling and pouch. The sling is just some gnarly pink pink twine we had around - its nylon, and has a tendency to unravel. The pouch was some extra chamois I had around from a leatherworking project, and a pair of grommets set into it. The release pin is a broken off piece of tinkertoy wood about 1/4" long. I had to sand down the end of it to make it round enough to let the sling slip off at the right moment. During testing on our firing range (the family room), I noticed I was getting very low trajectory - release angle was only about 15 degrees above horizontal. Optimum should be around 45 degrees. I puzzled about this for a long time, adjusting sling length - I realized that I needed to angle the release pin differently, but couldn't with the wooden peg. I ended up lengthening the throwing arm by one Yellow Stick [tm] and one Wheel [tm]. This apparently put the entire contraption into perfect balance. 45degree throws, and my small wooden blocks had now outgrown the family room. After removing a block or two from our drywall, I decided further tests needed to be done outside. Outside tests showed a mean range of approximately 30-35'. The distance was remarkably consistent, with no misfires and no 'wild shots'. Throwing 30' with a 12" throwing arm makes me really want to think about a full sized machine. I'll take a 30-1 ratio anytime. Update: 3/12/2002 : Videos! Todo: Trigger mechanism Larger scale - up payload to 1 lb Better sling / pouch arrangement Buy more tinkertoys.

Stay tuned for more updates and more graphics!

Last updated: March 16, 2002
Dave Belfer-Shevett
dbs@stonekeep.com