Sleeve gear installation problem

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mdt-son

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Hi guys. I am following the gearbox rebuild video by Chris Rooke

Now I am stuck with a sleeve gear too tight for the bearing ID. It was mentioned in another video that new sleeve gears supplied by AN appear to have a Dmax above the factory made sleeve gears, making the fitting a challenge.

So, this is now confirmed. I did freeze the sleeve gear overnight at -18 deg C (-0.4 deg F), yet it can't be pursuaded to go fully home. Luckily I was able to knock it out of the bearing before it heated up.

What's the remedy here? Should I try to heat the case and bearing a little? I can't go higher than 60 degrees C because of the rubber parts already fitted. I could cool the sleeve gear in solid CO2 (-79 deg C), enabling it to shrink more.
Or sanding the shaft using grade 1200 W/D?

- Knut
 
mdt-son said:
Hi guys. I am following the gearbox rebuild video by Chris Rooke

Now I am stuck with a sleeve gear too tight for the bearing ID. It was mentioned in another video that new sleeve gears supplied by AN appear to have a Dmax above the factory made sleeve gears, making the fitting a challenge.

So, this is now confirmed. I did freeze the sleeve gear overnight at -18 deg C (-0.4 deg F), yet it can't be pursuaded to go fully home. Luckily I was able to knock it out of the bearing before it heated up.

What's the remedy here? Should I try to heat the case and bearing a little? I can't go higher than 60 degrees C because of the rubber parts already fitted. I could cool the sleeve gear in solid CO2 (-79 deg C), enabling it to shrink more.
Or sanding the shaft using grade 1200 W/D?

- Knut
Click to expand...

In my experience, a home freezer is a waste of time when inserting things. Solid CO2 (dry ice in the US) is relatively easy to get (at least in the US) and will probably do the job. Liquid nitrogen would certainly do it but you would probably need the sleeve gear out to take it somewhere.

Beating them in usually means needing to ream them, as least the mushroom caused at the edge so avoid that if you can.

Unless you have the two-circlip type of sleeve gear, you want the bushing(s) tight as it is a mess when they slip out.
 
I would put them in a bath of oil for a day prior to fitting. The bushes are Sintered bronze. (oilite bushes)
andover-norton.co.uk

Andover Norton - SLEEVE GEAR BUSH (1.2

SLEEVE GEAR BUSH (1.2
andover-norton.co.uk
Put two of these instead of the earlier bushes and they hold more ridged in the 4th gear inside diameter. That way you don't need three bushes. That was a common Hack to fix the problem.
 
Am I misunderstanding the original post? I thought that Knut was concerned about getting the sleeve gear into the ball race, but the replies so far are talking about fitting the bushes into the sleeve gear.
IF Knut's problem is a sleeve gear too tight in the ball race, I had the same problem and resorted to careful use of fine emery cloth on the sleeve gear so that it fitted into the bearing with a 'firm knock', as shown in the video.
 
oldschool said:
IF Knut's problem is a sleeve gear too tight in the ball race, I had the same problem and resorted to careful use of fine emery cloth on the sleeve gear so that it fitted into the bearing with a 'firm knock', as shown in the video.
Click to expand...
Thank you. Is emery cloth grade 1200 appropriate, or should I select an even finer grade? I don't think an extreme thermal fit will do the shaft or the bearing race any good.

- Knut
 
800 will do, the courser the grit the more frequent the checking of size. If you have 1200 then use that for a final polish.
 
1200 will take ages. Don’t be shy, put in a lathe and use a strip of 180 grit emery cotlh.
 
Last edited:
had the same issue with a close ratio cluster from RGM and Andover bearing, resolved as suggested by ludwig in the lathe but with a skim pass using a carbide insert
 
I would measure the gear carefully to check if it is only one area that is too large, You can always spin it and use sand paper to remove some of the extra OD of the gear, Ideally it should be a light press fit as it will help to make a C-3 bearing have a little less slop and rocking of the fitted gear. A machine shop should be able to polish off a thou or two easily.
 
If the gear is too large, if you were to get it in, it might cause the bearing to lose all it's internal, clearance and turn hard . You really need to do some accurate measuring. A light press would be OK, But too much interference fit will /could be bad!
 
The question is, should you need to machine or sand the shaft? Maybe feedback to AN would be beneficial?
 
"So, this is now confirmed. I did freeze the sleeve gear overnight at -18 deg C (-0.4 deg F), yet it can't be pursuaded to go fully home."


Are you sure where fully home is?
IMG_6295.jpeg
 
Using a freezer is only reducing the temp by 30C (+12C to -18C) or so compared to a garage, that is nothing compared to the 200C you apply to a crankcase housing to get it to open up. Its a factor of 7 which is next to useless and steel has a lower coefficient of expansion than alloy.

Use the emery cloth.
 
I am not familiar with Chris Rooke's videos on a Commando engine rebuild.
I see there are a great many of them. Any comment on quality of the advice or the videos in general?
 
cliffa said:
The question is, should you need to machine or sand the shaft? Maybe feedback to AN would be beneficial?
Click to expand...
Actually, this seems to always be an issue for me. Old sleeve gears coming out of old bearings is no problem - snug slip fit.

Old sleeve gears in new bearings need a little sanding.
New sleeve gears in new bearings need a lot of sanding.
New sleeve gears in old bearings need a little sanding.

It appears that new sleeve gears are slightly bigger than originals (haven't bothered to measure).
It appears that new bearings are slightly smaller than those of 50 years ago (haven't bothered to measure and shouldn't be).

The basic problem is that the OD of the sleeve gear and the ID of the bearing must be the same for a correct fit. .001" off the wrong way and they are no longer a slip fit. Much more than .001" off the other way and they are a sloppy fit.
 
marshg246 said:
Actually, this seems to always be an issue for me. Old sleeve gears coming out of old bearings is no problem - snug slip fit.

Old sleeve gears in new bearings need a little sanding.
New sleeve gears in new bearings need a lot of sanding.
New sleeve gears in old bearings need a little sanding.

It appears that new sleeve gears are slightly bigger than originals (haven't bothered to measure).
It appears that new bearings are slightly smaller than those of 50 years ago (haven't bothered to measure and shouldn't be).

The basic problem is that the OD of the sleeve gear and the ID of the bearing must be the same for a correct fit. .001" off the wrong way and they are no longer a slip fit. Much more than .001" off the other way and they are a sloppy fit.
Click to expand...
and how about the O.D. of the bearings?
 

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