I don't like the stock mill handles. They work ok, but vibrate a lot and make noise, and don't feel too good to use. I made some quick replacements using some ABS rod and some cheap flanged bearings I bought on eBay. The fit of the bearings doesn't need to be precise in the ABS since the bolt will hold everything together. The bolt head was turned down and beveled to give it a nicer feel. Medium thread locker was used since there wasn't room for a lock nut anymore.
It works well and there isn't anymore noise. However, the cheap bearings I used feel pretty notchy with any pressure on them, so I might upgrade to better bearings if these wear out.