Alignment tool

coupling tool
Originally uploaded by Phil_Parker.

Turning the static Puffer into a full working radio control boat isn’t too difficult. The first job is fitting the motor.

All the experts stress the importance of keeping the motor shaft and propeller shaft in line. Although any slight disparity is taken care of by the coupling , the less this has to do the more efficient the drive will be.

I’ve used a coupling that is basically a universal joint with inserts in the end for the prop and motor shafts. Keeping this straight while fiddling around in the hull wasn’t going to be easy. So I made a tool.

The alignment tool is pretty simple. All it is is a brass tube slit along its length with four holes drilled in the sides to let the pivots poke through. The tool slides over the coupling and is clamped up solid.

I screwed the coupling in place and attached the motor. It still flopped around a bit but was held in place well enough to allow bits of wood to be shoved under to support it. Silicone sealant provides the “glue” holding things in place. Hopefully this combined with soft balsa supports will give a quiet drive system.