You need to be very careful here. These couplings are not intended to ever lock solid. Even when working correctly they will allow about 25% slip hot. If you lock it solid, you will overspeed the fan and it will disintegrate. At 5,000 rpm, the rim speed of the fan is in the order of 9,000 m/minute if the coupling is locked.
@@RangieNZ Indeed yes! I have seen people drill then and put a bolt through to lock them up rather than shell out for a new one. Disaster waiting to happen!
