I have a 1972 Enco version of the Rong Fu. Balancing drive pulleys can reduce vibration. Check the pulleys on your machine, if there are no lightening holes it has not been balanced. I had to drill 5 half inch holes about 3/16 deep in the large drive pulley that sits on top of the quill,, couldn't go deeper without interfering with belt surface. Made a difference. Lots of instructions on balancing on Google.