Rocket Tooling bp 0.5

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Problem statement

Making rocket motors requires precise repeatability and control. Ramming and drilling is a messy process which results in terribly nozzle quality, bad repeatability, and increased risk. Drawing up some tooling for 1/2" bp rockets would be a great way to get a motor that I can make again and again without the guesswork. I also want it to be end-burning so that the power can be dialed in with chamber length, as well as for ease of delay charges at the end of the grain.

Device Description

The tooling was made by Master Maine Machinist Gary Sweatt. I measured the amazing work he did and brought it into solidworks with the intent on reproducing it as well as for making variations at some point.


Lathe Profile

Drawn up in solidworks, will be posted soon.

Results

Fine clay coated with 5% toilet bowl wax (dissolved in xylene, mixed, and allowed to evaporate) makes a beautiful nozzle with a waxy sheen that is rock hard. I have not have a nozzle failure since I switched from motor oil to the wax.

Motors can be as short as 2" and as long as 5" though a high quality tube must be used to avoid burnthrough just above the nozzle (since it is as end-burner, this is where the flame will dwell the longest).