I recently acquired a used HF 8" x 12" lathe. It was like new. I disassembled the whole lathe into small assemblies in order to move it from the trunk of the car into my shop. After complete cleanup (it still had the factory shipping grease) I began to adjust it following tips from this and many other sites on the internet. My knowledge about machinery is almost null, took shop classes in High School about 40 years ago, so what is a big issue for me might be trivial to anyone else.
The original 5" 3 jaws chuck's runout, measured on a 1/2" drill rod, 1/4" from the chuck, was 6 mils. I took out the chuck, cleaned and oiled it. Installed it again (3 times) rotating the position of the chuck, respective to the spindle, each time (while measuring also measuring runout on each position) and found out that one of the positions was more favorable (measured runout approx. 4 mils). Marked the position with permanent marker on both the chuck and the spindle. Started looking for standard runout values for this kind of chuck and some people said that 2-3 mils could be considered OK, so I was not happy with my 4 mils runout.
I know that between the shoulder on the spindle and the boss on the chuck there is a few mils space, so I left the drill rod installed on the chuck, installed a carrier on the AXA toolpost and grabbed the rod on the free end with the carrier (by moving z and x for centering and the adjusting carrier's height with the adjustment nut) the setting screws on the carrier were not tightened. I rotated the chuck and found the minimum height of the rod. Marked the position on top of the chuck and tightened the setting screws on the carrier.
Now I loosened the 3 chuck holding screws (slightly), repositioned the mark on top and elevated the rod-chuck assembly approx. 2 mils by turning the axa carrier's adjustment nut, re-tightened the chuck and tested for runout. New measured runout is approx. 1 mil.
This procedure took about 25 minutes.
Best regards,
kreutz
The original 5" 3 jaws chuck's runout, measured on a 1/2" drill rod, 1/4" from the chuck, was 6 mils. I took out the chuck, cleaned and oiled it. Installed it again (3 times) rotating the position of the chuck, respective to the spindle, each time (while measuring also measuring runout on each position) and found out that one of the positions was more favorable (measured runout approx. 4 mils). Marked the position with permanent marker on both the chuck and the spindle. Started looking for standard runout values for this kind of chuck and some people said that 2-3 mils could be considered OK, so I was not happy with my 4 mils runout.
I know that between the shoulder on the spindle and the boss on the chuck there is a few mils space, so I left the drill rod installed on the chuck, installed a carrier on the AXA toolpost and grabbed the rod on the free end with the carrier (by moving z and x for centering and the adjusting carrier's height with the adjustment nut) the setting screws on the carrier were not tightened. I rotated the chuck and found the minimum height of the rod. Marked the position on top of the chuck and tightened the setting screws on the carrier.
Now I loosened the 3 chuck holding screws (slightly), repositioned the mark on top and elevated the rod-chuck assembly approx. 2 mils by turning the axa carrier's adjustment nut, re-tightened the chuck and tested for runout. New measured runout is approx. 1 mil.
This procedure took about 25 minutes.
Best regards,
kreutz
Last edited: