General Comments (Rocket Motor)

The rocket motors in this topic are built with hand tools, and this topic explains how– to make them. The best tools are made of steel or nylon on a metal lathe. To make a top quality casing retainer, you’ll need a milling machine and a welder. Properly made tools last the longest, and a properly made nozzle mold produces motors that actually work better.
For people who don’t have metal working equipment, I’ll explain how to improvise with things like plastic pipe, hose clamps, and wooden dowels. These improvised tools are primitive, but they work just fine, and they’ll provide you with enough experience to know if you want to make a further investment in the hobby.
If you want a better set of tools, you’ll at least need a metal lathe, or you’ll need someone with a metal lathe to make the tools for you. If you choose the latter, you can pay a machine shop. But first look for someone who owns a lathe. Most neighborhoods have at least one hobbyist, or maybe a retired machinist with a lathe in his garage, who will make things for people at greatly reduced prices. If you can’t find someone with a lathe, check with high schools and community colleges. Many schools offer adult night classes in machine shop, and some of my readers have taken advantage of these classes to make a set of tools, and learn a new skill in the bargain.

Figure 4-2. When the nozzle mold is removed, it leaves behind a divergent exit taper that aids the expansion of the motor’s exhaust into the atmosphere.

Figure 4-3. The parts diagram for a nozzle mold.