Bearing (?) in mind the wall thinness, and the hoop stress resulting from a press fit, might a Loctite product be safer?

Instead of press fit, could you use shrink or heat expanded fit ? Same limits and finished size, but less stress in fitting the bush (If you are quick enough).

Bob

I would use Locktite 620 retainer as that is designed to retain bearings etc with high strength and high temperature. You fit it with a slight clearance to allow the Locktite to work on a very clean surface so clean it very well with a solvent cleaner first. You don't have to allow for press fit just size on outside and slight clearance of a couple of thou but check the Locktite web site for details. I used it on parts in a plastic mould where it was heated by the plastic and loaded with a pin which had a rotary pull on the part in question.

David

To digress slightly, the usual way to fix something like this would be to grind down the damaged shaft, hard chrome plate and grind back to finished size. This us not the same as the decorative finish (bling) applied to cars.

The idea of har chrome platingb the bearing area and grinding back to original size appeals. (Keeps everythinbg to standard dimensions, although Imperial needle roller bearings may be becoming reare )

Unlike London Transport who used to grind worn shackle pins to their various standard undersizes, Southdown Motor Services used to have the pins hard chromed and ground back to original size. In this way, any pin could be used, in any vehicle.

Howard

Have a look at Glacier/oilite bushings, they give you all the information you need. Soft material thin wall bushes need a sized mandrel to create the correct size during deformation.

So that he can go back to a needle roller.

Dear Simon

With a four millimeter wall thickness on that diameter of bronze sleeve any push fit will damage the sleeve and distort it. I assume you want to take the needle roller outer shell out and the bushing to rotate within the outer shells housing.

Rather than a push fit, try as suggested above a heat shrink fit.

Put the shaft in the freezer wrapped in cling film and the bushing in the oven as high as your over will go.

When ready put the shaft in your vice with copper jaws get the bushing ready and a bit of pipe just over the size of the shaft, take the cling film off and it will remove the condensation and ice with it and lower the bushing on the shaft, being bronze it will have expanded a fair bit and should just drop in place if not use the pipe section to gently help it in place and then let it all come to the same temperature.

In regards to clearance this will depend upon the heating and cooling range but as its a gearbox assume it will be less than one hundred degrees i would allow two to three thou as your interfearance fit.

For my tuppence worth i would suggest making the bronze bushing a shrink fit in the housing and then shrinking or locktighting a thin high strength steel tube over the shaft roller surface and allowing that to be the running surface within the static bushing. however that may interfear with other items going onto the shaft and thats why you have chosen your approach.

BR Rolster

If the load is in one direction you're a lot better off having the steel shaft rotating in the stationary bronze bush. This is because ad the bronze wears the contact twixt steel and bronze remains a half moon shape, good for hydrodynamic oil film generation. If the bronze rotates in a stationary steel housing, the bronze just gets bigger all round. This is one reason why old fashioned wheelbarrows had the axle rotating with the wheel in rough cast iron bearings. Modern cheap ones with plastic wheels rotating on stationary axles soon develop wobbly wheels.

Might be worth contacting HCP in Mansfield – they mainly do motorbike forks, but I'm sure they will advise. No connection, just a happy customer.

Links to https://www.hardchromeplating.co.uk/

Rob