Custom fit cutlass bearing? Seek advice

[CarolineSE]

Hi,
The aluminium prop shaft tube in my gpr boat is 0.5mm or so wider than the new 1 1/2” brass cutlass bearing. (It still wiggles and slides easily) Any advice on how to pack it out? Can i eg cover the bearing in cling film and carefully smear araldite or other epoxy in the propshaft tube? Or add a layer fibre glass tissue around the bearing?
(would this also prevent corrosionbetween the metals?) or has anyoneused chockfast orange? Also attaches with grubscrews
Thank you in advance!
Caroline

 

[CarolineSE]

Or can a 40mm phenolic be carefully sanded down to fit?

 

[Malish]

should it have been a 40mm bearing?

 

[Tranona]

Brass cutless in an aluminium tube is not a good idea. suggest you contact here h4marine.com to have a custom composite bearing made which you can epoxy in. Much the best solution.

 

[LadyInBed]

You want something like this
Exalto GRP Shaft Bearing (25mm Shaft / 40mm OD / 100mm Long)

 

[CarolineSE]

should it have been a 40mm bearing?

The stern tube is 38.3 (above 38.1 but under 38.5mm) so size 38mm /1 1/2 brass bearing doesnt fit. But can get hold of phenolic bearing which is 40mm wide. Which is a better material as Tranona mentioned!

 

[penfold]

Have a 40mm phenolic bearing turned down to fit, removing 1mm or so won't make much difference although with phenolic care is needed not to overtighten the grub screws. Perhaps drill or grind pockets for the grub screws to engage in.

 

[Tranona]

The stern tube is 38.3 (above 38.1 but under 38.5mm) so size 38mm /1 1/2 brass bearing doesnt fit. But can get hold of phenolic bearing which is 40mm wide. Which is a better material as Tranona mentioned!

The bearing I am suggesting is not a cutless but solid composite. Better in your situation as you can have it made exactly to fit and epoxy it in. Probably longer lasting than a cutless as well.

 

[Neil_Y]

Thanks Tranoma.
Just to clarify, the ID of any bearing is made to be a known clearance on the shaft, the process of pressing in a bearing squashes the bearing slightly and reduces the ID and clearance. So it is important that the bearing maker knows how you intend to fit the bearing.

For a given shaft and carrier you have two options, get a press fit or a clearance fit. The ID's and OD's will be different. A clearance fit bearing can then be bedded on epoxy. A very thin film of epoxy holds the bearing in place but you can add grub screws. Ours are made to order so we make the bearing to suit the shaft OD and carrier ID you give us. You need to measure it acurately. You can buy them through Exalto UK. Ours are made by Maritex and are phenolic composite not rubber. They are perfect for aluminium as an epoxy fit as this does prevent any corossion hapening between bearing and carrier.