BEARING RACE CLEARANCE

[wrenchcruncher]

I need to bore a vertical drive housing from a boat, install a sleeve in a damaged area, then remove the bearing from the sleeve a few times for shimming. What clearance is required for this ?.
Any info would be appreciated.

[jalessi]

This might help.

http://www.kdtrading.no/tradingshop/...ok_enfield.pdf

[jalessi]

http://www.sterndrive.info/id10.html

[HuFlungDung]

The fit of the sleeve depends on how thick you make it, ie., how much oversize you bore the existing hole. As a general rule, we make sleeves approximately .050" wall. For a 1.5 to 2" bore, probably make it about .003" interference. Press the sleeve in and bore to final size. In this case, you'll want a snug push fit, one that you'll have to tap the bearing into place. This will be about .0003 to .0005 clearance, if you can measure both the bearing OD and the new bore accurately.

If you polish a bit of a taper at the front so that the bearing gets snug as it seats fully into position, this will make it less trying to install the bearing several times. Too tight and you risk scoring/galling effects, especially if you are impatient and get the bearing cocked in the bore on the way in. Lubricate the bore as you make each trial installation to minimize the chance of scoring.

If you get it too loose, there is always a Loctite product that will fix it up

[wrenchcruncher]

Thanks for the replies.
HuFlungDung your reply fits my application exactly . I bored the housing .150" oversize {that is what I needed to clean up the bore} leaving me with .075" wall thickness on my sleeve, the bearing race is 1.7". I used a .003" press fit for the sleeve to the housing and installed the sleeve. With the sleeve installed I get a bore diameter of 1.68", so I will need to remove about .0015 to .0017" .
Thank you
Not going to be easy though, this is a blind hole about 5" down and not much material left to remove?.

[HuFlungDung]

When the sleeve wall gets thicker, it is safe to reduce the interference fit slightly. If it is possible to set the part up for a final boring, then leave .025 to .050" to bore out of the sleeve. I should have added in my comment above that this is typically what we would do.

But, in some circumstances, it makes sense to try for the 'one-shot sleeve' where you carefully estimate the shrinkage the sleeve will take when installed, and bore it that much oversize before installation. In an aluminum housing, the housing is going to swell usually, so this means you won't get 100% of the shrinkage (due to calculated interference) in the sleeve. It is a bit of a crapshoot

For the amount you have to remove, the situation is difficult. Its a lot to remove by polishing, but we have sometimes resorted to using a flapwheel in an extended spindle die grinder to hand work a sleeve to size. But it is difficult to control what is going on, especially when the bore is blind and you need to polish right up to the shoulder.

Probably the way to do the one-shot sleeve (ie., totally finished sleeve OD and ID) is to reduce the interference fit to -.0005 to 0 and use loctite when installing the sleeve. This way you will not have to guess about which way things will shrink and by what percentage.