Monarch Flat Belt Lathe spindle runout

[alanmcd]

I have been refurbishing an 18 x 36 Monarch lathe vintage unknown. It is overhead flat belt driven via a manual (looks to be original) transmission. Every thing works great but there is about 5 to 7 thousands run out on the threaded 2 1/4" x 8 spindle. The internal taper (# 12 Jarno) exhibits the same run out but the shoulder next to the bronze bearing journal is dead on. It appears that the outer threaded portion is bent. How can I repair this or work around it? I have no documentation.

[harp]

I had a similar problem on my '27 LeBlond 14x40 lathe. I made new backing plates for the chucks. I bored and threaded the stock on another lathe,and roughed it in. Put the plate on the spindle and turned it true. Worked fine for me. You can also skim the threads on the spindle true, either way, your going to make new backing plates. Same with a center, cut the taper, put it in the spindle and cut the 60. You will have to mark the center and the spindle and always put in the same place to be true. Good luck!

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[h.w.evers]

Do you get the same runout when the drive belt is engaged and disengaged? Worth checking!