Split coupling for tapered prop shaft?

[Alex]

Hi everyone,

I’m looking to know if a split coupling for a tapered shaft exists. I know that these couplings work on an interference fit of the lapped taper and it may be impossible to get a good fit-up or lock on the shaft with this idea. Just asking

My shafts are 1-3/4″ OD, tapered at the prop and at the gear side. The issue is that the only way to remove the coupling to change out the Tides seals is to remove the engines with gears from the boat.

Why? There is only 2″ of movement back on the shaft when disconnected from the gear before it bumps into the seal housing/stern tubes, and that’s not enough to get a puller in front of it to pull the tapered coupling from the shaft.

With a split coupling, I could possibly remove the coupling by sliding the shaft out back, no puller needed?

Therefore leaving a clean shaft inboard to slide a new lip seal over it.

Any other options other than refitting with a traditional stuffing box and packing? There is no room there to mess with picking out packings and adjusting the nut.

Expensive solution: Changing shafts to straight end and get split couplings?

Thanks

Topic

[donald roth]

Moving the engine forward will move the propeller closer to the strut, you want about a shaft diameter of overhang between the strut and prop hub. <br />It will also entail raising the engine some to maintain alignment.

You may need a spacer in the coupling to keep that spacing correct.

A”Drivesaver” coupling insert is an easy solution, gives about an inch, or you could have a spacer made by a machine shop for a longer length.

[Alex]

Thanks for the idea Rob, I had never heard of the socket press method and it makes sense. Sort of like using an internal spacer that would press on the threaded shaft end and on the ZF coupler center bolt.

My concern is that I only have 2″ of clearance between couplers when unbolted and shaft is slid back against the dripless. May have to cut down a socket to get the socket and breaker bar in there to loosen the nut first, down to less than 2″ overall. I believe I takes a 37mm socket on that shaft coupler nut. Or a combination of cut down short socket and custom square drive handle as thin as possible with flat bar.

Then try the socket press method.

I could also try to move the engines forward another inch on the stringers, re-align shafts etc, which I’m doing anyways because the engines are out of the boat and I redid the front brackets with the SB kit to clear the raw water pump. Only that I have a bulkhead low in front at about crank pulley height that could impede front engine maintenance/removing the serpentine cover. Could also cut out the lower portion (crank pulley area) of the serpentine cover to aid in removing it forward and up when I need to.

[Rob Schepis]

Are you familiar with the “socket press” method?  Basically you place btween the shaft end and gear flange a socket slightly smaller than the shaft OD (coupler ID) and use longer coupler bolts (hardened fine thread is best) and systematically tighten the coupler back against the gear flange and let the socket press out the shaft.

Yea, I just repacked my traditional packing glad, so easy compared to tearing everything apart for dripless units. 

[Author]

Replies