I admit this seems like a question I should know the answer to, but I don't. I have a 25mm countershaft rod to fit two pulleys which have this bore. The countershaft supports on either end use bearings with 20mm bores. Without this lathe running, I have no machine capable of fitting a rod of this diameter (25mm) through the spindle. Hence, I will need to send it out. What are the tolerances I should be specifying?? ...both diameter and concentricity. The shaft is McMaster #1482K45 The spec's on that item are ∅ tolerance 0.0-0.0762mm and straightness tolerance is 0.3048mm per 305mm. Length is not critical because I can mount the supports as needed.
I guess I'm just confused if I would be better to send to a grinding shop or a general machinist local to me. Thanks for the help, guys. I appreciate it.