joeskeeter

My Feedback: (4)

The old Gruapner folding prop hub fits on the motor
that I installed on the old Graupner sailplane.
Whats a good way, aside from filing flats into the shaft, to secure the props onto the shaft?

BMatthews

If you don't want to rely strictly on pressure from the grub screw there really is no way.  A small single notch ground into the shaft with a small round Dremel grinding tip or a small round file that will just take the point of the grub screw about 15 thou below the surface will not do any significant harm to the shaft but will allow the screw to get deep enough to ensure that the prop can't spin on the shaft or come off the front. 

joeskeeter

My Feedback: (4)

I was hoping there was some work around.
Been out of rc about 2 years, just came back, and wow, there is
so much new stuff it's boggling.
Funny how some things still are the same, like grub screws.
Guess it's like the paper clip, broom etc.
Nothing works like an old fashioned paper clip, and no brooms work as well
as the old fashioned straw broom.

BMatthews

Yep, sometimes the tried and true works best.

I've seen collet style prop adapters spin in the shaft during high current full power "switched" startups.  I've seen those same collet adapters and prop go flying off the front of the motor as well.  And this was after seeing the guy really torque down on it.  Our motors just don't have shafts large enough to generate the friction needed in a pure clamping system to adequietly hold high power props onto the sort of motors we can get now.  So we come full circle back to a notch on the shaft and a grub scew or two.