The Thruster Assembly
Step 6

MATERIALS: 3 propellers 3 bushings Wax TOOLS: 2 Metal cups Lead sinkers Electric hotplate Potting holder Pliers Vice Drill 5/32" drill bit 7/64" drill bit Eye Protection

1. Drill a chamfer into the grooved end of each propeller with 5/32" drill bit. (A chamfer means drilling just a TINY bit around the top edge of the hole: just enough to round the edge of the hole so the bushing can slip inside. This is easiest with a drill press. Otherwise, use a vise and be careful not to over-drill)
2. Drill a chmfer into the wide end of each bushing with 7/64" drill bit. (Drill just a tiny bit off the edge of the hole so that the motor shaft can be pushed in).
3. Using pliers or a vice, push the bushings into the propellers. Be careful that they go in straight!
4. Put a small (2") piece of PVC pipe on the back of the motor and press the propeller/bushing onto the motor shaft with a vice (Fig. 12B). Be careful not to bend the terminals, and make sure the propeller goes on straight and tight.
5. Once all the propellers are attached, place the three thrusters into the potting holder and fill the film cans with wax to the top, creating a positive meniscus (see Figure 12D). (USE PLYERS TO GRAB HOT METAL CUPS!)
6. Put caps on the film cans (be sure wax does not have air pockets).

WARNING! HOT WAX CAN SQUIRT OUT! WEAR EYE PROTECTION!

A. Propellers and bushings		B. Attach propellors to motors with a vice
C. Fill the film cans to the top with wax		D. Positive meniscus