Prop Shaft Part I


Part 162, the prop shaft and prop drive accessories, from EN24 steel as supplied by Wren .

  This shaft was turned in a fashion similar to the turbine shaft. Since the procedure was almost identical, I will not go into the same detail as I did earlier, but will focus instead on modifications I made and to the prop drive accessories.

The shaft blank was faced to length, and roughed out first with the shaft in the lathe chuck rather than between centers. Here, the pinion (gear) end is being roughed for the pinion and the rear, dual bearing set.

The shaft is flipped, and the propeller end is roughed. As I did for the turbine shaft, carbide tooling was used to within 0.010" / 0.25mm, and the special, high-rake HSS tool to within 0.002" / 0.05mm. Note the lack of drive cone... Mike uses a 8 degree cone. I am going to deviate a bit there. Hang on and you'll see!
Roughed out to within .002" / .05mm, the shaft is centered for the final sizing. The high-rake tool is again honed to high sharpness with a diamond stone.
For details on polishing the critical journals to size, again refer to the turbine shaft. The major front bearing is shown in place, and the pinion is a nice, snug fit as well. The center portion of the shaft, which resides inside the prop shaft housing, was turned to exactly 0.5625" / 14.29mm to possibly accept at a later date a cut 32 DP, 16 tooth imperial spur gear form. The premise here is to some day draw power from this gear form, via an idler gear, to an accessory gearbox. The gear remains uncut for now.
I made my prop shaft 10mm OD, which is the same diameter as the inner race bore. The end of the shaft was threaded 3/8" x 24.

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