holding the shaft stationary while torqueing the prop nut – how?

[BabaYaga]

In my view the OP's issue are two fold.

1) The torque he is trying to tighten to is too high for the setup the video says 45 ft lbs

2) the wood prop he wa using was just too soft to support the torque he was trying to set

Would like to know what the supplier says about torque requirements

1) It may well be the case that 220 newton-metres (162 ft lbs) is too high. It was a number I picked up when this task was at hand, from a source that seemed to be reliable (don't quite remember what source it was). Thinking about it now, it seems natural that the torque requirement would vary with the diameter of the prop, shaft, shaft thread etc.
When visiting the manufacturers web site, browsing the manual, it says that the nut torque is stated in the documentation that came with the prop. I am pretty sure that it was not (but this was in 2006, maybe it is nowadays).
2) Yes it was too soft, given the high torque aimed for and the fact that I did not dare to let the blade take the force. I would easily have been able to set the nut to 45 ft lbs, though.

In answer to posts # 39 and 40:
The shaft is 25mm and the thread is M16 fine.

 

[rotrax]

Plus Torque Wrench is vulnerable to bad thread etc ... its why when I raced - we used 'torque washers' ..... washers with tabs on that crushed at the torque levels ...
Guy would use normal spanner - with a feeler gauge to check when reached required torque.

I suppose such old solutions are not used now ?

The 1936 to 1956 Triumph 500 Twin manual told you to measure the big end bolt with a 2-3 inch micrometer.

Then assemble, tighten gradually until the bolt had stretched .003".

Possible with this type of engine which had a crankshaft around which the engine was built. Not like a car or marine engine where getting a 2-3 inch mic in place would not be possible.

 

[penberth3]

Plus Torque Wrench is vulnerable to bad thread etc ... its why when I raced - we used 'torque washers' ..... washers with tabs on that crushed at the torque levels ...
Guy would use normal spanner - with a feeler gauge to check when reached required torque.

I suppose such old solutions are not used now ?

Indicating washers are still "a thing", a very clever thing too!