I agree with aquinob a vfd is the way to go here is my drill press with vfd and 1/2 hp motor
https://www.garagejournal.com/forum/threads/buffalo-no-15-drill-press-acquisition.510408/
Good luck trying to find and get a new spindle. page 38 new departure old catalog https://7000765.fs1.hubspotusercontent-na1.net/hubfs/7000765/Knowledge Base/New Departure Hyatt/New Departure Hyatt Ball Bearing Catalog 2C-110 (1957).pdf the pulley bearings should be 6205 type
Here is a chuck I have, Jacobs 633C it came off a delta wood working radial drill press from the 70's, will check its runout. the locking collar thread is 1-1/16" 20tpi. Locking collar chucks are required if you side load, such as using a drum sander or wire wheel
yes, you will send the quill and spindle, it will take 2-3 day turn around $50 plus shipping . I may have a good jacobs chuck for you.
here is a link to my old drill press https://www.garagejournal.com/forum/threads/buffalo-no-15-drill-press-acquisition.510408/#post-10358592
I only had to take off a few thousandths. Your spindle runout under a thou should be fine as long as chuck has low runout . Std chucks have advertised runout of .003-.004"
to remove the spindle pulley, I have used a heat gun and light taps with a rubber mallet . here is my buffalo 15. It has not been repainted.
https://www.garagejournal.com/forum/threads/buffalo-no-15-drill-press-acquisition.510408/#post-10358592
Nice drill press rebuild, the spindle taper can be reground, I reground my spindle after installing new bearings in the quill. I got less than 2 tenths run out .0002" at the spindle
the TS does not switch the neutral, it is a 2 pole wired to a small old 20k. space at this location is tight and that is why the trailer genset will be used and stored at another location