Author Topic: Main shaft keyway damage  (Read 709 times)

Offline a101960

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Main shaft keyway damage
« on: 14.08. 2017 10:59 »
I am trouble finding a new main shaft for my gearbox. The keyway is damaged on the one that I have. Would it be safe to assemble the clutch without a woodruff key (that’s how I found it when I took it apart). I have read that the most important thing is how tight the fit is on the taper is this correct? Actually, I do seem to remember that the fly wheels on BMC Minis were had no keyway so this does seem to be probable. What are  your thoughts on this? As a matter of fact my clutch nut was done up really tight, so I was wondering if I used  Loctite, and did the same would it be OK? In all other respects the shaft appears to be in good condition.

Offline duTch

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Re: Main shaft keyway damage
« Reply #1 on: 14.08. 2017 11:13 »
Quote
......Would it be safe to assemble the clutch without a woodruff key (that’s how I found it when I took it apart). I have read that the most important thing is how tight the fit is on the taper is this correct?.....

 Sorry, but doesn't seem like a real good idea to me...to make it hold you'd need to do it up REAL tight, and that makes undoing REAL hard...I think someone not long ago suggested carving a keyway in the other side of the shaft..(?) seems a better idea to me.

  Maybe you could try Auto-cycle engineering, I think they make shafts and are Gold Star buffs (I think)
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Offline JulianS

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Re: Main shaft keyway damage
« Reply #2 on: 14.08. 2017 12:06 »
I agree with duTch.

Key essential.

Make sure you dont buy an RRT2 shaft it wont fit your sleeve gear.

There are some seriouly strong loctite products available, not the usual ones we use on our bikes, it is worth looking at their website if you decide to go that way.

How bad is the damage ?

Offline muskrat

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Re: Main shaft keyway damage
« Reply #3 on: 14.08. 2017 12:23 »
Me three. The taper is self locking BUT the key is there incase it doesn't. The key is also designed to shear (should be softer than the shaft) if a lock up happens. A lose key is better than no key.
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Online Greybeard

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Re: Main shaft keyway damage
« Reply #4 on: 14.08. 2017 13:36 »
On my old Austin Seven I had an enlarged key slot that I filed up a stepped key for.

Online cyclobutch

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Re: Main shaft keyway damage
« Reply #5 on: 14.08. 2017 15:32 »

...I think someone not long ago suggested carving a keyway in the other side of the shaft..(?) seems a better idea to me.


That would be my suggestion.
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Offline a101960

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Re: Main shaft keyway damage
« Reply #6 on: 14.08. 2017 16:13 »
OK here are a couple of pictures of the damage to the main shaft keyway. I think that it is well and truly past its sell by. Anyone got one they want to sell?

Offline coater87

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Re: Main shaft keyway damage
« Reply #7 on: 14.08. 2017 19:58 »
 Honestly, if our tapers were machined right the key is redundant.

 But its very hard to find a main shaft that does not have key damage, I have looked. Is this because nobody tightens the nut? I dont think so...I think its because our taper fits sucked from day one and the bike had to rely on the key the whole time.

 I really believe you can save that shaft. You need to clean it super well, including the inside of the adapter and the key slot itself. Preferably with something that leaves no oily residue (spray electronics cleaner for instance) or even loctite primer.

 Use green loctite sleave retainer. This is the serious stuff (will require heat to remove). Put a couple drops in the keyslot, make sure the key is clean, and lightly smear it on the taper. Dont get it near any bearings, or they will lock up tight.

 Put it together as soon as you put down the loctite, dont use it on the threads for the nut or it may require heat and an impact wrench to get off.

 This stuff is very strong, and is used regularly on much more demanding stuff than our clutches.

 I just bought a new main shaft from DeGroot because mine was bent. The key way looked like yours and I had used loctite just like I described. This is what its made for.

 Lee

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Online trevinoz

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Re: Main shaft keyway damage
« Reply #8 on: 14.08. 2017 22:06 »
I would NEVER Loctite a clutch sleeve to a mainshaft.
I have seen the grief it causes when it comes time to remove it.

Offline coater87

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Re: Main shaft keyway damage
« Reply #9 on: 14.08. 2017 22:55 »
I would NEVER Loctite a clutch sleeve to a mainshaft.
I have seen the grief it causes when it comes time to remove it.

 I agree with this as far as removal. I had let my adapter set up for about 3 days before I needed to remove it again, It required a decent three jaw puller and 10 minutes with a Map gas torch. The only thing worse was if i needed an impact on the puller. Not easy.

 I dont believe you will get it back off with the puller that threads inside the diameter of the adapter, i am pretty sure you will just remove the threads.

 But thats the trade off.

 I blued my shaft and adapter, I would like to see 75% contact or better on a taper fit so it can work. I had between 20 and 30%, a really poor fit. So I played around with all the odd junk bits I have, and the best fit I got was near 50%.

 You can lap this fit in with grinding paste, and a lathe if you have a lot of time. I think we would all be long gone by the time you lapped a 20% fit shaft and adapter if you did this by hand. These are both hard, hard, parts so neither acts as a charged lap for the other.

 If you install a poor fitting taper and key, no matter how much you tighten it, its going to roll and damage the shaft. Then you are right back to a bad key way in a new shaft. *sad2*

 IMO, loctite is the way to go here. But exactly as Trevor pointed out, plan for removal to be as bad as it gets.

 But you wont roll the key in a new shaft. Or because of the loctite you can get by easily using a straight shaft with a damaged key way.

 I guess its up to whether you have the means to remove it again available to you.

 I use loctite 640 (green) for stuff like this.

 If its really, really worn, replace it or try loctite 660 (silver) and plan to throw it away next time its apart- because you should have replaced it last time. ;)

 Thats how I do it, but each to his own.

 Lee

Central Wisconsin in the U.S.

Online chaterlea25

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Re: Main shaft keyway damage
« Reply #10 on: 14.08. 2017 23:00 »
Hi,
I wont enter the loctite discussion  *eek*
but,
New mainshafts are available from Autocycle Engineering in Dudley
and De Groot in Holland
Even though I'm sure these originated from Autocycle ??

John
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Online bikerboy

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Re: Main shaft keyway damage
« Reply #11 on: 15.08. 2017 01:15 »
I dont know where you are but somebody like Coventry boring and metalling can probably repair that.

I sent them a crank that was mullered a lot worse than that and they repaired it no problem, it was not that expensive either in my opinion

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Re: Main shaft keyway damage
« Reply #12 on: 15.08. 2017 04:47 »
OK here are a couple of pictures of the damage to the main shaft keyway. I think that it is well and truly past its sell by. Anyone got one they want to sell?

My key way is not much better than that. I just made up my own key that was a tight fit in the slot depth. The bought new key was able to move 020" up and down so just made one a little thicker. My home made one was thick enough to just stop the clutch centre taper contacting properly under hand pressure, but the clutch nut was still able to push the centre on and hence make the taper "bite". To get the good fit I wanted the key ended up thicker on one end than the other indicating the slot depth varies along its length.

My theory was that the key could not "roll" if it was a tight fit between the shaft and centre, and hence it could not get bent out of shape enough to come out of the key way, it would have to shear.
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Offline a101960

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Re: Main shaft keyway damage
« Reply #13 on: 15.08. 2017 10:54 »
To everyone that has given advice and suggestions I thank you all. John, De Groot do not have any A10 mainshafts, and I have emailed Autocycle Engineering in Dudley, I await their reply and I will let you know how I get on with them. Bikerboy, I have also emailed Coventry Metalling also awaiting a reply. Draganfly have them listed as "available to order" but I am a bit wary about going down this route because I am well aware of the notrious Draganfly back order system that never seems to deliver. I have heard tales of people waiting for years for Draganfly back orders. I have no machining facilities, nor for that matter do I have any mechanical apptitude so any of the suggested work rounds are way beyond my abilities. Once again thank you all for the contributions that you have posted, I will let you all know how I get on.
John

Offline a101960

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Re: Main shaft keyway damage
« Reply #14 on: 15.08. 2017 12:45 »
Well, I have had a reply from Autocycle Engineering, and wouldn't you just know it, they are out of stock. They are going to make some more, but it will not be for a few weeks, but they did say that a Goldie one (which they do have in stock) could be used with a simple mod. I have emailed them back to find out more. I am assuming this would entail some machining which I cannot do so I am no further forward. Looks like the bike is off the road for the forseeable future. Old bikes, who would have them eh?
John