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I bought a new drill press and I am converting it to variable speed. I bought a 3-phase motor and am driving it with a VFD. The motor shafts of the motors are a different size so I had a machine shop bore out the the pulley. I think they got the bore off-center just a tad because the motor vibrates badly when I connect the belts. It doesn't vibrate without the belts, even when I jack up the speed to 200%. My question is would a link-belt help or is the only solution to replace the pulley? If I need to replace the pulley, can someone recommend a good place to buy a pulley. Specs: 55-70 mm in diameter with a 24mm bore and a 6mm keyway. The original pulley is stepped but I don't need the steps now I have a variable speed motor.
Doing it right cost less than doing it over
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10-21-2016, 01:54 AM
(This post was last modified: 10-21-2016, 01:55 AM by daddo.)
If the pulley fits snuggly on the motor shaft, the pulley can be mounted on an arbor shaft trued to the lathe, then the pulley turned true again as long as not too much material must be removed. The shop should have checked that.
Once you have determined that it is indeed the pulley and not a flat on the belt or a motor shaft with runout- have the pulley fixed or buy another.
You might try;
http://www.mcmaster.com/#pulleys/=14otcsu
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In my opinion, keeping the multiple groove pulley would be a good idea anyway. I refitted my lathe with a VFD drive and motor but kept the original 4-groove pulley set. I can slow the spindle with the speed knob (in a fraction of a second) but lose torque or slow it by changing the pulley ratio (several seconds) and gain torque. What I'm turning determines which method I use but it's great to have the option. I suspect that drill press operation would be similar.
We do segmented turning, not because it is easy, but because it is hard.
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Well I ordered a new pulley, a single step as finding a multi-step with a 24 mm bore has been an exercise in futility. I'll try this out for a while as I still have the center and quill shaft step pulleys still in place,, so that gives me some variability. Time will tell if it works OK. My next task is to get the Hall Effect sensor mounted, a box to hold the LED readout, and hookup a pot to vary the speed. Radio Shack carries the pot but my local store was out-of-stock. In addition, I need to run new 110/220 service next to the drill press. I need 110 for the wall wart for the digital readout and the internal light on the drill press, and 220 to run the VFD.
Doing it right cost less than doing it over
