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ID knurling tool and bore sleeving advice?

I have several rear hubs from vintage race MG Midgets that have spun their bearings, and I need to find a repair. The problem is that this is a single ball bearing taking all loads, and by the time you put triple the horse power through far stickier tires through them they last about 300 miles. The symptom is the outer race gets loose in the bore allowing the hub to wobble due to the increased loads. The bearings themselves are fine. Hub is forged steel. This was fine when we had a seemingly endless supply of rear hubs to throw at the cars, but they are now becoming pretty scarce.

The proper fix is to install a second bearing behind the first, but that requires a custom machined hub. When you do that there isn't enough room to put in a seal that actually lasts, so instead of spinning the bearing you get rear end grease all over your rear brakes.

So what I want to try to do is improve and repair the press-fit between the bearing and the hub. My first thought is to try to knurl the ID to raise the surface to get a big press fit. This coupled with Loctite may work. the second idea is to sleeve the bores. There isn't a lot of room to open out the bore to take a sleeve, so how thick a wall does the sleeve need? What material for the sleeve?

Does anyone make an ID knurling tool or should I make one?

Thanks, Brian

Reply to
Brian
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Sounds very much like the MGA rear hubs.

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Not sure whether this will work or not, given the loads which are causing the problems.

Agreed -- clean the surfaces, prime them, and use the LocTite bearing retainer compound. The knurl may give better surface area for the LocTite to grip.

I would first experiment with steel shim stock. I think that the brass shim stock would not handle the loads involved, and would creep.

Hmm ... I've got one, but it would not do you any good. It is a cut-style knurler crossed with a small 3-jaw chuck. It can cut either OD or ID, but since it cuts, it would not raise the metal as you need.

What is the OD of the bearing/ID of the bore? Perhaps one of the T-bar knurlers designed for turret lathe operation could have the holders reversed to handle the ID of the bore.

Other than that, I would suggest a deep study of tool catalogs.

Good Luck, DoN.

Reply to
DoN. Nichols

By boss just did in ID knurling at the shop. He temporarily pulled a knurling wheel off a tool and I made a simple holder with a small piece of drill rod where I turned the end down to fit the hub of the knurling wheel, allowing it to spin freely. That was it -- just chucked it up and it worked. I thought the wheel might come off, but the forces hold it on.

-Bruno

Reply to
Bruno

. My first thought is to try to knurl the ID to raise

There is a readymade steel sleeve used in electric motor repair. Called a "tolerance ring". Don't know if it would work, but it might beat trying to use shim stock.

I've sleeved a bunch of hubs over the years that were no longer available. Set up and bore the hub, no larger than needed to clean up. Final wall thickness of the sleeve can be as thin as .010". Machine a ring that is a light press fit, but has enough wall thickness to press in. Loctite it in, let the loctite set, then set it up and bore the ID.

Bill

Bill

Reply to
Bill Marrs

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