HP-24 Project

Update 16 October 2006: Radius Machine Finished

This weekend the family and I did some rock climbing up at Box Canyon (across the highway from the Bear Valley village) on Saturday, and on Sunday I finished off the radius machine and gave it a test. I also packed up some stuff to go to Brad's place for Akaflieg Monroe II, and also packaged some legacy HP kits.

The biggest piece of work on the radius machine was making the translation drive for the routing carriage. I knew I was going to use a 5-foot chunk of 3/8-16 threaded rod to drive the carriage, with the threaded rod engaging some sort of nut on the carriage. But I also knew that I needed to be able to disengage the carriage from the threaded rod so I could quickly reposition it along the rails. It seemed pretty obvious that the solution would involve a half-nut with some sort of clamping device to engage and disengage it from the threaded rod, and I spent an hour or so sketching clamping mechanisms before I realized that what I needed was already available in the five-dollar bin at the local Ace hardware.

Here's the basic parts of the translation drive release: Some 3/8" ID tubing cut in half, a 3/8-16 coupler nut cut in half, and a pair of cheap vicegrip type pliers.

And here's the release assembled. Note that the half-nut is welded to the lower jaw (which will be on top in our application)...

...And the unthreaded half-tube is welded to the upper jaw.

Here's the drive release welded to the carriage.

And here's an overall vew of the machine with the translation drive in place. Note the drive crank at the far end of the machine.

This shot shows the completed machine with the router in place, after test-cutting a chunk of 2x4.

And here's two pictures of the test-cut 2x4. The cutting isn't as nice as I'd want for a control surface, but is pretty close and the radius is perfect. The crescents at the ends of the cut are because I had the cut set too deep, and because I over-deflected the piece. I think I'll probably make a set of tools for adjusting the depth, and also make deflection stops when I start to work on real control surface plugs.

We spent the Saturday before my Shop Sunday at Box Canyon; mostly playing around on an easy route called Sweet Sophia. It's a six-bolt lead route for kids that goes at like 5.2 or so. Here I'm getting Raen tied into the toprope for a go at it.

Brigitta lowering Raen off afterwards.

Alia tucked away up in a niche next to the route. She doesn't like the roped climbing all that much, but she loves to scramble up 4th class terrain like this.

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page updated 16 October 2006 all text and graphics copyright (c) 2006 HP Aircraft, LLC