Sometimes the pf is written on the motor rating plate, might be worth a phone call to see if one of the lads can see it marked on the plate.
Anyway with a mill esp if its a later one theres usually a speed control for the spindle, either a dc or ac drive, usually to comply with directives such drives have built in power factor correction.
I think you need to contact the machine manufacturer and see what they say about the expected pf.
Where I work we have extrusion machines for polymer, they use lots of energy, and the heaters are inductive as when the pf machine had a failed cap bank the pf went down as low as 0.28, us the maint department aere a little embarassed when the first we knew of it was when the power company came and told us.