Cutless bearing/shaft question,slightly different

[saltyrob]

Hi Folks,

Have established that shaft is worn. Rather than fork out for replacement, as watching pennies I am thinking of machining present 1 inch shaft to 25 mm and getting slightly smaller cutlass bearing. The machining would only be for the length of the P bracket housing the bearing, as we have a rope cutter fitted which is designed for an inch shaft and similar prop boss. Therefore would there be an issue sliding a bearing designed for a 25 mm shaft along the inch shaft and into the P bracket.

Hope this describes the situation

Many thanks

Rob

 

[cmedsailor]

Will the smaller cutlass bearing be tight in the p bracket and not walk its way up the shaft?

 

[cmedsailor]

Just to add, you will need a custom made bearing. Outside diameter for 1 inch shaft and inner diameter for 25mm shaft.

 

[saltyrob]

Hi

Standard cutlass bearings are available with an outer shell of 4 inch x1.5 inch to suit P bracket for either a 25 mm or 1 inch shaft . So the bearing would fit in the P bracket and I guess the shell thickness or rubber lining is slighty larger to suit the smaller 25 mm shaft. Once the bearings is in the P bracket should be no problems ,but the bearing would have to slide from aft along the 1 shaft shaft into the P bracket and cannot reduce the size of shaft where rope cutter /prop fitted.

Hope that it explains a bit better

Many thanks

Rob

 

[Tranona]

Hi Folks,

Have established that shaft is worn. Rather than fork out for replacement, as watching pennies I am thinking of machining present 1 inch shaft to 25 mm and getting slightly smaller cutlass bearing. The machining would only be for the length of the P bracket housing the bearing, as we have a rope cutter fitted which is designed for an inch shaft and similar prop boss. Therefore would there be an issue sliding a bearing designed for a 25 mm shaft along the inch shaft and into the P bracket.

Hope this describes the situation

Many thanks

Rob

It will only work if you machine the entire length from in front of the P bracket to the taper. Then your rope cutter will not fit. Really no sensible option but a new shaft. Remember 25mm is smaller than 1" so you cannot slide a 25mm bearing down a 1" shaft.

 

[SteveIOW]

Concur with Saltyrob that cutlass bearings for metric shaft (25mm) with imperial OD (eg 1.5" OD) are available. Speak to T. Norris Ltd re their Part No W25I.

Hope this helps.

Steve

 

[HunterWanderer]

These guys really know what they are talking about. :

http://www.mylocalservices.co.uk/Norfolk/Marine_Engineering/912082/Brimbelow_Engineering.html

No link. Just a happy customer. They machined and balanced a prop for me and result is A1.

 

[LadyInBed]

Whatever you do you have to take the shaft out, which is hardest part.
What are you going to do with the cutter?
- Ditch it
- Shim and bodge it
- Buy a new one, which will cost more than a shaft!
Who would want to buy the boat from you with a non standard shaft?

Do it right, get a new shaft, you will have to at some stage of the game.

PS Did you read this thread?
http://www.ybw.com/forums/showthread.php?387920-worn-propeller-shaft-at-cutless-bearing

 

[wee_niall]

does sound like your in a similar position to me, although if you're going from 1" to 25mm you're only reducing the shaft by 0.4mm and if the advice on my thread is right about the tollerance being 0.6mm it's probably not worth the effort....my shaft is worn by over 1mm which is why i kinda need to do something

 

[robmcg]

Unless your shaft is super long (no smirking at the back), buy a new one. They aren't prohibitively expensive. Better fix long term than a lash up!