I want to modify the bearing seats of a hub to enable it to take a larger diameter axle and end caps. It’s not a lot of material to take off but my local machine shop are not used to ‘holding’ a hub in the lathe so will have to make a mandrel or something, increasing costs and faff. I’m looking for a bicycle hub-friendly machine shop. I was thinking Goldtec but any others out there?

Couldn’t you just buy different bearings with smaller balls in them (because I know ball diameters can be changed from bearing to bearing).

I don’t know anywhere that will take your hub but they might also encounter problems with the free hub, you know, freehubbing whilst they are trying to cut the material.

With most lathe chucks they just can’t go wide enough for the flanges on the hub so it would need steadying at both ends and then you could only machine the outside so yeah, I don’t blame them.

For the amount that you are probably looking at wouldnt it be worth selling the hub and buying the correct one?

With most lathe chucks they just can’t go wide enough for the flanges on the hub

The flanges might not be centred to the bore either, which would mean using a four jaw and faffing about to get it centred.
I’d be inclined to think the turner knows what he’s doing and let him get on with it, but then I did used to work in a machine shop.

A new hub would be cheaper than paying my old rates.

Kinetics?

It’s a front hub. I’m getting it modified because I have a matching set of front and rear hubs in anodised light blue to match my Yeti. The rear hub fits, the front one needs to be modified to fit the 15mm front axle.
I’m hanging on to the hubs for sentimental reasons.

I have done similar things in the past – I think I did it by chucking up on the internal bearing race on one side, doing the other side, then swapping.

Update:
I took maximusmountain’s suggestion and have just ordered some different size bearings. It may be easier than I thought, just the 15mm adapters to machine which should be very simple.

Basically, I’ve got some Ringle Radium hubs from a Cube Stereo which are 9mm front and I want to use them with 15mm front. Looks like I can do this with minimal machine shop effort.