What about one of the companies that do fork stanchions already?

Same process & procedure, Stuart, but fork stanchions have the advantage from a re-plating POV of being parallel - weapon of choice here being a centreless grinder.

First pass to get the old chrome off & down to pit-free clean steel is basically an eyeballing job - no setup as such, just keep letting the stanchion feed itself though the machine with an increased infeed each pass until it cleans up.

After chroming much the same untill the surface is clean, then start to measure and adjust the machine to get size.

Gearbox shafts are multiple diameters & have splines. Most likely require to be set between centres on a cylindrical grinder, with stops set to avoind hitting features other than that being worked on. May need to do this on more than one feature on the shaft, before and after plating, so more labour than putting a parallel shaft through a centreless grinder.

I am out of touch with pricing these days, but I can't see a specialist grinding company (or even a general jobbing shop) working for under £60 an hour (+ Vat) these days, so multiple setups will cost even if the plating isn't too expensive. Last job I had done was probably 10 years ago now - "sorting out" a bent tailstock barrel from a CNC lathe after a "coming together" with the tool turret due to a programming error. 100mm diameter hardened steel barrel with a 5MT socket and, post collision, a 0.05mm bend. Repair was to grind out the bend on the OD between centres, plate oversize & grind back to size then touch up the taper socket true to the OD - cost around £400 + Vat IIRC and that was a relatively straightforward job that didn't require much material removal.

Nigel B.