I had a 3" diameter (X 2') shaft reduced by a machinist friend. He
chucked it up and sanded it to size, then polished it with finer
sandpaper. Didn't take much time, 5-10 minutes. Being a friend, he
didn't charge me, but I would think any charge would be nominal.
If you have a local tech school nearby, a student might do it for a
gratuity fee. This would be a task a student is capable of.