I' m about to put a jackshaft-mounted pair of pulleys on a drill
press for lower speeds. Does it matter/is there a best place to put
the shaft? I'm trying to figure out if it is offset on the drive
side will the forces on the bearing be more balanced.

On Mar 13, 6:52*am, jackshaft wrote:
I' m about to put a jackshaft-mounted pair of pulleys on a drill
press for lower speeds. *Does it matter/is there a best place to put
the shaft? *I'm trying to figure out if it is offset on the drive
side will the forces on the bearing be more balanced.

The commercial wide-range drill presses have two short belts with
three cone pulleys, the center one is usually pivoted eccentrically on
the center post to provide for tightening both at once. The offset
doesn't seem to give undue wear on the bearings, but I've not seen one
that's had 60 years of wear yet. How low a speed do you want? Lowest
I've seen with the above arrangement was like 40 rpm. Has been
several articles in various model-making and home shop mags about
retrofitting a 5 speed press to that arrangement in the past, some
even going so far as to machine the v-belt cone pulley for the center.

Stan

I saw a setup for speed reduction where the main motor had a double
shaft, with a pulley on the bottom shaft, belted to another motor
mounted to the column at a decent reduction. Just so long as one doesn't
apply power to both motors at the same time, seems like a fairly easy
solution.


Jon