@@huuphuocnguyen6924 Thanks for the promptness you used a stepped pulley, what speeds do you constantly use at the chuck to machine?! I noticed you made a speed reducer I tell myself that you are surely working with output speeds of 200 revolutions then 300, 400 and 700 at most I feel like reaching 1000 revolutions for the workpiece is too much Thank you for sharing you are very inspiring we learn a lot