G4003g Motor Vibration Surface Finish Issues Fixed!!

Excellent. As a new G40003G lathe owner (whose lathe is still bolted to the pallet and has never been turned on) I found this interesting.

My lathe skills are zero, so I assume my surface finish issues will be more of my doing than the lathe when I get started, but this is good data to have in my back pocket. Thanks!
 
coolidge said:
... I did not demonstrate much of a difference between the motors. If anything I dispelled the theory that its the cheaper China motor causing the surface finish issue.
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I don't know, it looked to me like the motor took you about half way. Regardless, maybe you should strip the motor off before you sell the lathe and keep it for a future modification.
 
tmarks11 said:
I don't know, it looked to me like the motor took you about half way. Regardless, maybe you should strip the motor off before you sell the lathe and keep it for a future modification.
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There was significant buzz in the lathe from the Baldor motor even with those thick rubber washers. If I had bolted the Baldor motor on like I had the Grizzly motor bolted on, metal to metal I'm pretty sure the surface finish would have been similar, perhaps a bit smoother eliminating the WHA WHA WHA Whooo of the Grizzly motor. If I have to pull it back off maybe I'll test that and report back. I just don't want people rushing out to buy a new motor thinking that will fix something. Since the isolation mounts are so cheap, less than $3 each I think people should try those first before dropping $324 on a Baldor motor, just my 2 cents worth. The Baldor will be included with the lathe when I sell it, its almost certain I will go 3 phase with a VFD on my next lathe.
 
abrace said:
Excellent. As a new G40003G lathe owner (whose lathe is still bolted to the pallet and has never been turned on) I found this interesting.

My lathe skills are zero, so I assume my surface finish issues will be more of my doing than the lathe when I get started, but this is good data to have in my back pocket. Thanks!
Click to expand...

You may as well order up the isolation mounts. I had to re-drill and tap the motor mount because the knuckleheads at the factory drilled the holes too far to the left, resulting in the motor being too far to the left, so they just hung the pulley half off the end of the motor shaft to align it with the drive pulley on the lathe (face palm). So if you have to go to all that trouble you may as well install the isolation mounts while you are at it.
 
coolidge said:
You may as well order up the isolation mounts. I had to re-drill and tap the motor mount because the knuckleheads at the factory drilled the holes too far to the left, resulting in the motor being too far to the left, so they just hung the pulley half off the end of the motor shaft...
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Cut the knuckleheads some slack. Wasn't their fault that the print said to drill those holes...

I got to believe that because my G0709 is the same way. Different model lathe, with the same drive pulley only half engaged with the motor shaft.... I am betting that the crude cast iron motor bracket was designed for the original 12x36 lathe, and doesn't really fit the current models but they are using it anyhow....
 
Couple of thoughts: All induction motors have discontinuous torque, which tends to make them vibrate about the axis of rotation. The simplest solution may be to use a motor mounted in a cradle with rubber rings. This type of motor is readily available and normally used to drive HVAC blowers. Three phase motors have less vibration for the same reason an engine with more cylinders tends to vibrate less. If a single phase motor does not have a run capacitor, adding one can reduce vibration noticeable by bringing the "start" windings into play as additional "cylinders." Other things being equal, a DC motor running on a well-filtered supply is usually very quiet and vibration-free. But one running on a plain SCR drive without filtration will NOT be either. Likewise, a three phase motor running on a VFD may or may not be quiet and vibration-free. Lots of ways to approach this aside from shock-mounting the motor.
 
UPDATE: Okay two issues, first the isolation mounts positions the motor just enough to the rear that the belt rubs on the lathe end cover, it goes on but you can run it that way. As I mentioned in a previous post there's not much room inside the cover. Second issue is with the motor hanging sideways on the isolation mounts the two at the rear are not looking too happy. The pulley helps support the motor at the front but I think the motor is going to have to be repositioned to sit flat.
 
I started to do this a few times, but when I see the huge 3 hp motor sitting in that tight place on the bottom with bolts that are so hard to get to, I decide to get to it tomorrow which is today, but there is always tomorrow.
There are great isolators used on HVAC compressors with rubber that goes through the bolt area- I might try these as I have a few of them. In fact, I might just do that today.
 
Mounting the motor in the horizontal plane sounds like a lot of work and trouble for a machine that you are planning on selling. Probably would have been close to the same price to drop a 3 phase motor and something like a Teco 510 VFD drive, and you wouldn't have to deal with the motor capacitors interfering with the mounting. But then, one never foresees all the bumps in the road.

You may ultimately need to look at other type of mounts, something with a mounting plate with an embedded thread nut for the motor bolt. You also may be better off making a new motor mounting plate out of plate steel or aluminum to mount the motor/feet, and slot the plate for adjustment. Some of the motor manufactures also sell low profile motor adjustable mounting plates. http://www.leeson.com/Literature/pdf/1050/MotorAccessories.pdf

One of these vendors may be able to direct you to a mounting system for vertical mount shear system,
http://www.vibrasystems.com/product...ry-mounts/compression-shear-mounts-19/lf.html
http://us.essentracomponents.com/sh...unt:---1-2-13-threads---hole-diameter-1105130
 
Converting to 3 phase adding a VFD and controls would have been a LOT more expensive and I'd still have the same issue with the motor having to sit flat on isolation mounts caps or not. This Baldor is no larger than the factory motor in diameter and actually a bit shorter end to end. So while a 3 phase motor would get the caps out of my way and that would be quite helpful, the expense and additional work of a 3 phase VFD conversion cancels that out. Just my 2 cents. IF I was planning to keep the lathe then there's no question I'd do the 3 phase conversion.
 
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