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Gearbox tailshaft bush

Posted: Fri Jul 17, 2020 11:40 pm
by pgp001
Does anyone happen to know the exact outside diameter of the propshaft where it enters into the tailshaft bush and seal etc.

My spare gearbox looks like it could benefit from a new bush, I have a 1.1875" machine reamer that looks to be about right but I have no spare propshaft to measure up to make sure.

Thanks
Phil

Re: Gearbox tailshaft bush

Posted: Sat Jul 18, 2020 8:51 am
by Murrayminor
My 1098 propellor shaft measures 1.1875" or 30.16mm where it enters the gearbox.
Hope this helps.

Regards
Dermot.

Re: Gearbox tailshaft bush

Posted: Sat Jul 18, 2020 11:25 am
by pgp001
Hi Dermot.

I wonder what the actual dimension of the finished bush is supposed to be, maybe a little larger than 1.1875" to give it a running clearance.

I will ask the bush suppliers and see if they can tell me.

Many thanks
Phil

Re: Gearbox tailshaft bush

Posted: Sat Jul 18, 2020 12:04 pm
by Murrayminor
If you had asked last week, I have just fitted the end oil seal so cannot measure the Bush now.

Re: Gearbox tailshaft bush

Posted: Sat Jul 18, 2020 6:30 pm
by win
I used my adjustable reamer when I did mine many years ago, just made it a running fit.
You can borrow it if you need it, I live in South Yorkshire, but it will not cost a fortune to post it.

Regards Win

Re: Gearbox tailshaft bush

Posted: Sat Aug 29, 2020 6:27 pm
by pgp001
Just a quick update.

I managed to extract the old bush by making a top hat shaped tool to pull it out using some 16mm threaded rod.

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The new bush was a LOT tighter to re-install, and it would only go back in if I heated the aluminium casing to expand it a bit.

This is my solution for sizing the bush, I have a 1.875" machine reamer but not one that is 0.002" oversize, and to be honest I am not a big fan of adjustable reamers either.

So I decided to make myself a Go - No Go gauge and bore it out on the lathe instead, I used the fixed steady running on the plain spigot where the seal housing fits.
It went very well and luckily it would just clear the bed without removing the long studs. the whole job only took about an hour or so.

Phil P

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