Shaft Taper Adapter

Such a sleeve won't be "off the shelf" but an engineering firm just might make you one if provided with all the necessary dimensions including keyways etc.
I'd suspect cost would make the exercise uneconomic.
 
Might be cheaper to get a 1" shaft machined down to 3/4" over all its length except for the taper end (only 1/8" to be removed), but the step between the two would need to be radiused to avoid a stress riser and shearing off.
 
I agree with early bird, the cost of manufacturing something like this would be quite high, possibly near the cost of new prop, I
I would guess that it's not just a matter of making the adaptor, but it may have to be welded into the 1" prop to be totally secure?
My drive shaft is a 3/4" and I recently replaced the prop, a new 12x8 prop cost me about £200, but of course Major Clangers prop may be much larger.
 
Major_Clanger said:
Thanks all for your input, much appreciated.......

I've seen the shaft reducers on coopec's link (thanks) and thought EUREKA, but they aren't tapered. Prop size is 13 x 10 or thereabouts and must be either folding or feathering.

I like the idea of turning a shaft down, and I do have a lathe so that might be the way ahead.
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If you do go down that road, try to leave as much space as possible between the end of the 3/4" bit and the root of the keyway and if possible get the keyway machined so that its root has a radius rather than a step - a tip an engineer gave me once, he having had one he'd made shear off at the root of the keyway. Sharp angles are to be avoided.
 
Major_Clanger said:
This is a partly rhetorical question, but I'm wondering if it's possible to buy a tapered spacer to allow my 3/4" shaft to accept a 1" prop? Not able to afford a new prop and the choice is far greater for 1" shafts.

Any ideas? :)
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Yes

Bore out the prop and fit a bush that then can be bored out and keyed to suit the propshaft.
 
3/4 is quite skinny for a shaft.
Are you sure it will be stiff enough for the new prop?

One could just roll a shim into a cone and put it between shaft and prop?
You might get away with letting the shaft go further into the prop so the shim cound be less than 1/8th.
 
TernVI said:
One could just roll a shim into a cone and put it between shaft and prop?
You might get away with letting the shaft go further into the prop so the shim could be less than 1/8th.
Click to expand...

Yes that is a possibility but have you tried to roll a piece of 1/8 " think stainless steel in to a cone of that size.

I have done something similar using stainless steel tube 1.6 thick by splitting the tube then pressing it into a tapered hole in the prop, but I would not try it with 3.2 mm thick.
 
Charlie Boy said:
I’d have thought a new prop shaft would be a much better solution. Probably cheaper too.
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Probably.
New cutles bearing is a service item anyway. Can the P bracket take a bigger bearing?
New flange or bore out the old one?
New seal or stuffing box?
Adds up to a few quid.
If one was looking at secondhand folding props, could a new hub be an answer?
 
Many years ago I needed a 1" propeller fitting to a 3/4" shaft, a local engineering firm cut the hub from the 3/4" prop I had and turned it down to fit in to the 1" propeller taper then they locked it in-place by drilling and tapping down the taper joint between the hub and the 1" prop and fitting long grub screws.
The boat has had several owners since I had it but the propeller is still the same.
 
Lots of small engineering companies will do this type of work for less than buying off the shelf. I had some corrosion on a shaft and got a piece shrunk onto it and then turned down in a lathe. After a new engine, it was too short so I then had a new shaft made - bought the bar stock and took it to them to put the taper on. Charged me £70 cash for the latter.

I love the smell of cutting fluid ...

ps: I still have a good length of 30mm 316 left over in case anyone is looking.
 
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Thanks again for all your replies.

I found a company in the States who supplied a tapered adapter and key to fit over my existing 3/4" shaft. The adapter is some form of plastic though which I'm sure can't be strong enough - though they've assured me it will be as it'll only have to cope with 10hp. It certainly fits fine but I may try to replicate it in steel to be sure. Will let you know how I get on.
 
TernVI said:
3/4 is quite skinny for a shaft.
Are you sure it will be stiff enough for the new prop?

One could just roll a shim into a cone and put it between shaft and prop?
You might get away with letting the shaft go further into the prop so the shim cound be less than 1/8th.
Click to expand...
NO NO NO
 
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