QA-42A - blew up the input gear today

[sblunier]

Harry,

Some of those had holes in the stub shaft in line with the keyway. A cotter key in that hole trapped the key in the keyway, and it couldn't back out against the housing, so key stayed put. Not a tight fit on the key, and probably (eventually) more keyway wear, but still effective.

I prefer the 2 set screw versions and still use the cotter key "safety".

 

[mpatterson]

Harry,

Some of those had holes in the stub shaft in line with the keyway. A cotter key in that hole trapped the key in the keyway, and it couldn't back out against the housing, so key stayed put. Not a tight fit on the key, and probably (eventually) more keyway wear, but still effective.

I prefer the 2 set screw versions and still use the cotter key "safety".

Mine has the hole in the end of the shaft for a cotter pin. Never seen that before - was actually wondering if it was a PO modification? Guess not. Thanks for answering that question Steve!

 

[hydroharry]

Harry,

Some of those had holes in the stub shaft in line with the keyway. A cotter key in that hole trapped the key in the keyway, and it couldn't back out against the housing, so key stayed put. Not a tight fit on the key, and probably (eventually) more keyway wear, but still effective.

I prefer the 2 set screw versions and still use the cotter key "safety".

Steve - yes, some of them ONLY had the hole for the cotter pin and NO set screws at all. I never understood this either. The driveshaft had one set screw on the end that connects to the gearbox, and NO set screws on the end that connects to the chain sprocket shaft. I always wondered WHY it was only some of the driveshafts.

 

[sblunier]

A few pics of my gear box with 2 set screw u joint and safety cotter key

 

[jdrong]

Mine had a cotter pin too. I believe it kept the drive shaft from falling off when the set screw came loose. I tried a longer set screw with a lock nut and blue loctite didn't stay tight. Drilled and tapped for a second set screw, now it stays tight.

 

[sblunier]

That cotter key is a cheap insurance policy!