Cutlass bearing for imperial shaft and metric tube

[sailingpangolin]

We have the somewhat odd situation that our boat (Contest 41 of 1989) has a metric stern tube (45mm) but an imperial shaft (1 1/4) which was retrofitted at some point.

Now after dismantling the old cutlass bearing it turns out it is impossible to find this combination. Lots of imperial tube and metric shaft options out there but not the other way around…

Any help to point us to a supplier is highly appreciated!

Measures:
Shaft: 1 1/4
Tube: 45mm
Length of fitting for bearing: 120mm

[Engine man]

Johnson makes a model "BITE" [has a brass shell] cutless bearing with an OD of 50.80 mm, and ID of 1.25". Any machine shop can turn it down to 45mm. Joe

Originally Posted by sailingpangolin

We have the somewhat odd situation that our boat (Contest 41 of 1989) has a metric stern tube (45mm) but an imperial shaft (1 1/4) which was retrofitted at some point.

Now after dismantling the old cutlass bearing it turns out it is impossible to find this combination. Lots of imperial tube and metric shaft options out there but not the other way around…

Any help to point us to a supplier is highly appreciated!

Measures:
Shaft: 1 1/4
Tube: 45mm
Length of fitting for bearing: 120mm

[PippaB]

Welcome to CF Pangolin. You don't say where you are located, which may make a difference.

There are standard 30x45 and 32x45 bearings that you could probably make work. The 30 would have to be turned to trim the interior, but that is not too difficult a process. I'm guessing the 32 would work off the shelf and provide adequate support, but there would be much less room for wear and thus you would be replacing more often. There are also places that can build you a custom unit (most likely by turning the ID or OD of some stock unit ) but that will be both time and money.

[RaymondR]

I would not machine the inside, they are usually designed with water passages to allow cooling and lubrication and machining out the inside would alter these.

Consequently your options would appear to be to use a larger OD bearing and machine it back or a smaller and increase it's OD with a sleeve.

[Ballsnall]

Originally Posted by PippaB

There are standard 30x45 and 32x45 bearings that you could probably make work. The 30 would have to be turned to trim the interior, but that is not too difficult a process.

The 30x45 would be my choice and have a shop bore to out to 11/4". The water grooves are plenty deep enough to take out 30 thou without any detrimental effect. You could probably do it yourself with a drill and buffing wheel.

A standard 1 3/4" X 1 1/4" cutless would also work fine, just bond it in with locktite or sikaflex.

You could also make up a boring tool or use a reamer and machine out the stern tube to a standard imperial size. No more future issues.

[sailingpangolin]

Thanks all for the suggestions!

I think we will go for the correct fit on the OD so 30x45 as the bearing is in the deadwood and really difficult so remove which makes bonding it in with adhesive a pain when it needs to be removed.

We are situated in Preveza, Greece, so metric options are plentiful here.

[stormalong]

1.75 inch is 44.45 mm so if you get some .25 mm brass shim stock it will be just about perfect.

[Ballsnall]

Originally Posted by sailingpangolin

I think we will go for the correct fit on the OD so 30x45

If you are keeping the vessel long term, you can probably get two machined up for the same price, it's just a quick skim with a boring bar, then you have a spare.

[sailingpangolin]

Just to let everyone know: We opted for sanding the rubber piece to 1 1/4''. I did this manually with a small wood piece and added layers of ductape to increase the diameter. See pics. It was a bit of laborious process but worked out ok in the end. Thanks to everyone for your help!