You can machine a hardened shaft if the machinist has the right tooling. I think it requires a ceramic tip, but that's beside the point. If it's the length that is the problem, just cut it off with a grinder and file down the burs.
If it is the diameter of the shaft, you may just want to swap the bushings. Get your old one out and measure the outside diameter. Then measure the diameter of the shaft to get the inside diameter you need for the new bushing.
There is a company called Bunting that makes bushings and they are very cheap (like less than a buck) and they have them in thousands of sizes right off the shelf. Motion Industries and Applied Industrial Technologies are just two of the many suppliers that stock them.
The part numbers are pretty easy. They start with CB for cast bronze, then the inside diameter in 16ths, the outside diameter in 16ths and the length in 8ths.
Example: CB0814-08 =1/2" inside, 7/8" outside, 1" long
or CB1220-06= 3/4" inside, 1-1/4" outside, 3/4" long
Find one of the above listed suppliers and go check them out. It will be a lot cheaper than having one machined.
I guess I'll let you have that info for free even though you lured me in here with talks of money.
