Failed to remove the shaft coupling

[fisherman]

Use the gearbox flange, it's held on with a nut so not going to affect the G/B, not going to push the gearbox shaft out. basically it provides a robust puller, put a spacer on the shaft end, four bolts through the flanges, oil on the nuts and washers ,and wind up. You are only pressing the halves together, no endways pressure on the gearbox, as long as you don't start with the hammer.

 

[Hurricane]

Use the gearbox flange, it's held on with a nut so not going to affect the G/B, not going to push the gearbox shaft out. basically it provides a robust puller, put a spacer on the shaft end, four bolts through the flanges, oil on the nuts and washers ,and wind up. You are only pressing the halves together, no endways pressure on the gearbox, as long as you don't start with the hammer.

The OP said above that he doesn't want to risk damaging the gearbox flange.
I think his current approach is to do the same as you are suggesting but with a steel plate/disc instead of the gearbox flange.

 

[fisherman]

The OP said above that he doesn't want to risk damaging the gearbox flange.
I think his current approach is to do the same as you are suggesting but with a steel plate/disc instead of the gearbox flange.

OK. Can't see what damage would be possible. An old knackered flange would do for a puller.....

 

[Mistroma]

The OP said above that he doesn't want to risk damaging the gearbox flange.
I think his current approach is to do the same as you are suggesting but with a steel plate/disc instead of the gearbox flange.

Yes, I spotted that. Perhaps he was under the impression that he was pulling on the flange. Most flanges are pretty thick and strong. I didn't even consider a puller with mine, just a spacer with longer bolts to squeeze the flanges together and some heat.

It is a puller, because it is pulling the coupling off the shaft. OP should think of it as a "pusher" because it is pushing the end of the shaft by applying compression between both flanges.

It was several miles to reach somewhere selling bolts and I decided to get a guy with the proper tools. Guess what, he used longer bolts, a steel billet and some heat.

 

[Boater On Thames]

@Croftie Yes. It's metric 45mm.

 

[Boater On Thames]

Yes. I just received some 120mm long bolts and just waiting for a piece of 20mm thick steel plate to do that. I will avoid using the gearbox flange because I don't want to damage it, and it's too little room between the gearbox and its flange. It is very hard to tighten the nuts there.

 

[John100156]

@Croftie Yes. It's metric 45mm.

Can be difficult to distinguish, I checked my shafts before ordering new lip seals, they were 1.3/4" very close to 45mm:




Anyway, I think we are all looking forward to your final post, advising us that you have been successful and all is well again.

Wishing you every success....!

 

[John100156]

Just a thought, as 1.3/4" is so close to 45mm, could 'they' have possibly heated an 1.3/4 flange, and then fitted it to a slightly bigger 45mm shaft? Would make it blooming tight when cold, although I doubt it what with the key....

 

[TK Blue MAX]

Just a thought, as 1.3/4" is so close to 45mm, could 'they' have possibly heated an 1.3/4 flange, and then fitted it to a slightly bigger 45mm shaft? Would make it blooming tight when cold, although I doubt it what with the key....

Half a mm is massive on shaft fits, you would need the flange almost molten to get a 1 3/4" onto a 45mm shaft

 

[fisherman]

too little room between the gearbox and its flange. It is very hard to tighten the nuts there.

Get round that by putting bolts in from the shaft end, nut on g/b end, with an extra nut at the bolt head, which you wind in while holding the bolt head if needed. But it sounds like you are nearly there anyway.

 

[John100156]

Half a mm is massive on shaft fits, you would need the flange almost molten to get a 1 3/4" onto a 45mm shaft

I remember (many years ago) when I was rallying and rebuilding engines, we use to heat up the con-rods before pressing-in the gudgeon pins to assemble the pistons - not sure what the rate of expansion was...!

 

[Falling Star]

Yes. I just received some 120mm long bolts and just waiting for a piece of 20mm thick steel plate to do that. I will avoid using the gearbox flange because I don't want to damage it, and it's too little room between the gearbox and its flange. It is very hard to tighten the nuts there.

I do wish you luck with it and hopefully that will work. Doing it that way, there is a risk that the threads may strip before it releases.
Take your time and maybe continue using heat and some taps with a hammer as you tighten the nuts.

 

[burgundyben]

I remember (many years ago) when I was rallying and rebuilding engines, we use to heat up the con-rods before pressing-in the gudgeon pins to assemble the pistons - not sure what the rate of expansion was...!

You only need a few thou! Not half a millimetre!


Hole Expansion Ratio, HER, quite a complex set of calcs with a number of factors.

 

[John100156]

You only need a few thou! Not half a millimetre!


Hole Expansion Ratio, HER, quite a complex set of calcs with a number of factors.

Well, I did say it was just a thought....!
I will stick to my area(s) of expertise, but like others, just can't wait to hear the mighty crack and confirmation its all released...!

 

[Bandit]

Its a British Fairline I am sure they are all inch and three quarter. Mine was and every Turbo 36 and Sedan I have seen is.

 

[Croftie]

Its a British Fairline I am sure they are all inch and three quarter. Mine was and every Turbo 36 and Sedan I have seen is.

I asked him to double check, he said "@Croftie Yes. It's metric 45mm. "
Probably in a week will be asking how to shim up a 1.75 shaft to fill a 45mm coupling

 

[oldgit]

The boat is of USA manufacture ?

 

[Boater On Thames]

Yes. Made in the USA.

 

[Bandit]

Yes. Made in the USA.

Sorry my mistake I thought it was a Fairline 36 turbo, I apologise.

 

[Boater On Thames]

@Bandit. No worries. I appreciated your input.

Finally received the 20mm steel plate. I am going to drill holes on it today and try it on the coupling tomorrow.