pa_pyro Posted August 18, 2008 Posted August 18, 2008 Very nice tooling! I made a wooden device for my mini rockets.(same tubes you are using here). I drilled a small hole all the way through the block of wood with a drill bit sized for the nozzle. Then I drilled halfway through the block of wood with a drill bit that fit the tubes OD, perfectly centered on the first hole. To make my mini rockets I ram a clay plug, ram the BP, then the final plug or mini payload, then insert the tube into the block of wood, and drill up through the bottom of it to make a perfectly centered nozzle/core. Also 50mg crackers make the perfect salute for these rockets, they fit inside perfectly and the rockets lift them fine.
Swede Posted August 18, 2008 Author Posted August 18, 2008 I've made that style of tooling now for the bottle rockets (1/4" ID) and 4 ounce (1/2" ID). When I machine stuff, I usually just do it on the fly with calipers, gauges, and such - so that means no prints. I'll try to get some CAD going. The block aluminum, NASA-grade screw-down tube support works exceptionally well, but I can already tell that the practical limit for most people is going to be about 1". The problem is in creating the hemispherical concavity on each block. It can be done with a ball-nosed end mill, a boring head, or a very large drill, but drilling straight holes above even a measly 1/2" requires a pretty stout machine. I've tried to come up with alternative tube support systems for larger tubes without much luck yet, nothing beyond the standard steel tube, slotted, with a welded lip for screw clamps. It's a tricky problem. The factories in China probably have hydraulic dies that whip open and closed rapidly, and automated tamping machinery, for their bigger rockets. Wish we could do that!
Aquarius Posted August 19, 2008 Posted August 19, 2008 Hmm. I tried the same approach as Swede on the tooling for minidrivers. Works well, and a nice small practice for my lathe and milling machine. Now, on earlier projects I have used wood, 2 by 4's, drilling out the hole without clamping them together. Works well, sometimes the driver gets stuck in the wooden clamp, but a few whacks does the trick. And it's cheaper and much easier for prototypes than aluminium ones. And since my hydraulic press came in yesterday, I now have a new excuse for making more toolings.
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