The model's engine
power is transferred to the propeller by a propeller shaft. It exits
the hull through a "stuffing box". The stuffing box is a slightly
larger tube filled with grease or oil. This lubricates the shaft and keeps water out.
small models a simple stern tube can be made from 1/16 inch brass
rod and a 1/16 inside diameter brass tube, about 2 inches long ,
which is glued directly into the hull. A K&S tubing cutter is
ideal for cutting the stern tube to length, although I’ve also
used a razor saw, cutting the tubing and a scrap piece of rod inside
it at the same time.
Use a hobby knife to de-burr the ends of the tube.
I used the Lindberg propeller, drilling a 1/16 inch hole into
it and then super glued the shaft into the propeller.
I use a light grease (Vaseline) to lubricate the shaft and
then install the shaft into the tube, adding a tiny washer at each
end, and a 1/16 inch collar with a set screw to hold everything
together. (All parts readily available at most hobby shops).
shaft must be long enough to reach the flexible tube coupling with
simple stern tube has no lubrication
reservoir, but the grease keeps everything watertight, and the
collar acts as a thrust bearing.
This design is only appropriate for small models.
Larger models require a more involved stuffing box. The shaft rides
on two "bearings", one at each end of stuffing box.
An oil tube is soldered to the stuffing box. 3-in-1 oil
is filled in the tube and this keeps the shaft lubricated and water
tight while operating.
For a instructions on building this type of shaft visit Old River Bill's
Shafts by Graupner
If your not ready to build
your own shaft there are a number of scale drive systems made
by Graupner. These range from 6.7” to 13.8” long and cost between
$11.00 and $17.00. They are threaded to take a
4mm thread size propeller. Also
available are reduction gears to fit the shaft.
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