Propeller Shaft - Stuffing Box

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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
For 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 Ive 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). 
The shaft must be long enough to reach the flexible tube coupling with the motor

This 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.

Tom Hynes

Large 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 web site 



Other ideas 

Propeller 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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