Grizzly G4003G - Installed rubber motor mounts, fixed motor alignment, pulley, wiring issue

[coolidge]

I made some more improvements to my G4003G lathe by fixing some quality issues and installed some thick rubber washers to dampen vibration from the motor. Lets start with the quality issues...

Notice how far the pulley sticks out on the shaft, pretty lame.



Here's another pic, unacceptable imo PLUS the pulley was bored so poorly it wobbled a like it was made of jello. Luckily the replacement pulley arrived from Grizzly today 2 weeks earlier than expected! Replacement pulley was straight and true.



Here's why the pulley was sticking out so far on the shaft, the factory drilled the mounting holes too far to the left so the only way they could align the motor pulley to the spindle pulley was to hang it out off the end of the motor shaft (facepalm) Also note how they snaked the two cables through this mount e.g. between the motor and the motor mount, I re-routed one of these above and the other to the left of the motor, this allowed me to bolt the motor onto this motor mount while on the work bench WAY easier.



Here I have re-drilled and tapped the motor mount holes 5/16-18 relocating the holes about .400 inches towards the headstock. I also picked up some large 1/8 inch thick rubber washers at my local hardware store to dampen any vibration from the motor, I added smaller 5/16 rubber washers between the mounting bolts and motor, I used some grade 8 bolts I hand on hand. I have read where a few guys have isolated the motor from the lathe with rubber and this improved finish, meh I figured it couldn't hurt while I had everything apart. Also for the three large bolts that bolt this mount to the lathe, the CHINA washers were not so great, one was already bent inwards into the slot from the factory. I picked up some grade 8 thick washers to replace them.



This was the next quality issue, I had to unwire the motor to remove it, see the red wire lower left its missing a washer. I wondered why this wire was loose during disassembly, I found out later without the washer the screw bottoms out in the hole leaving the wire loose. I added a washer to fix this.



Here I'm using my digital angle gauge to align the motor parallel to the spindle pulley shaft, this tool makes it easy. I used a wood block and some wood shims to hold up/position the left side of the motor while I set the belt tension and tightened the right bolt. I also aligned the pulleys vertically.



Certainly closer than I could have eyeballed it. Notice how much farther onto the motor shaft the pulley is now, its nearly flush with the end of the shaft.



Buttoned everything up and celebrated with a cold beverage.

 

[darkzero]

Good job. Curious about the rubber washers you used for the motor. Have you tested it & seen an improvement on finish?

 

[coolidge]

Darkzero I have not tested it yet, finish so far has been 'okay' not exactly mirror like. Most of the reports I read where guys isolated the motor was due to poor finish when threading and in testing threading on my machine the finish was in fact not very good, but I was using the brazed on 60 degree bits during those tests I have an indexible threading tool now which I have yet to test. I'll get around to testing this over the weekend.

 

[Dog]

I have been through this with this model lathe. The problem with using rubber to isolate the motor is it will compress and not do much except make your belt adjustment not hold. I ended up using this http://www.mcmaster.com/#standard-vibration-damping-pads/=rkru19 These pads are used for setting machinery on and don't compress much. I also had to install new bearings and balance the motor. That finally got the finish to acceptable but what a pain in the butt. Good luck.
[h=3]High-Capacity Oil-Resistant Nitrile Vibration-Damping Pads[/h]

5940K51

High-Capacity Nitrile Vibration-Damping Pad, Oil-Resistant, 12" x 12" x 1/2" Thick, 1500 PSI Cap

 

[coolidge]

Dog these are dense heavy rubber washers they did not compress much, others I found were too soft though.

 

[AlanR]

To really use rubber washers for vibration damping you need them on both sides of the motor mount. I have some specially made mounts and bolts, there's a upper rubber washer and a lower. They have a stepped, reduced diameter that fits into the motor mount so there's no metal to metal contact at all.

These were originally used for sewing machines, we had a bunch of them.

I'll try to post a picture later on.

 

[AlanR]

Here's a picture.



Nothing to stop you from using two short ones except for the length of the bolt.

In this picture I believe I have the rubber mounts reversed. The bolt (a fancy carriage bolt) goes through the table top and the motor hangs below. I used them with the long rubber part below the motor mount, I figured the weight of the motor needs the most cushioning, they're pretty soft. I used nylock nuts.

 

[drs23]

Well this is perfect timing. The motor on my G4003G died Monday. After jumping through the hoops Grizzly Tech Support put me through to determine it was actually a bad motor like I had been telling them for two days they're shipping a warranty replacement.

coolidge,

I found my motor pulley out about that far as well with the key sticking out an inch or so past the face of the pulley. Also found the setscrew completely missing. That must be the screw I found floating around when I uncrated it originally and couldn't find where it went.

Have you reassembled your motor/lathe yet? If so, can you tell any difference or enough difference that it made your mod effort rewarding?

I also noticed you installed NAPA belts in lieu of the factory installed Gates. What was the reasoning behind this. I ask because I was considering going back with adjustable link belts. I used some on an Atlas I used to have and it make a noticeable difference.

AlanR,

Where did you score your specialty thru-damper bolt. That sounds very intersting. Are they still available? If so, where? I've got the rubber washers that Dog mentioned on the way from M/C as of now.

Thanks for posting guys. Great timing!

Dale

 

[AlanR]

Well this is perfect timing. The motor on my G4003G died Monday. After jumping through the hoops Grizzly Tech Support put me through to determine it was actually a bad motor like I had been telling them for two days they're shipping a warranty replacement.

AlanR,

Where did you score your specialty thru-damper bolt. That sounds very intersting. Are they still available? If so, where? I've got the rubber washers that Dog mentioned on the way from M/C as of now.

Dale

I'm in an old sewing plant and there's tons of stuff kicking around. I have no idea where they came from but I'd bet a sewing machine parts supplier would know.

You might find the rubber pieces at mcmaster.com You can make your own metal parts.

 

[coolidge]

Here's a picture.

View attachment 74666

Nothing to stop you from using two short ones except for the length of the bolt.

In this picture I believe I have the rubber mounts reversed. The bolt (a fancy carriage bolt) goes through the table top and the motor hangs below. I used them with the long rubber part below the motor mount, I figured the weight of the motor needs the most cushioning, they're pretty soft. I used nylock nuts.

Alan this is what I have done, the large rubber washer on one side and not known in the pics is a smaller rubber washer under the bolt head and washer. My machine seems to run smooth the motor seems balanced so I didn't feel the need to go with thicker dampeners that could dampen a shaky motor. Mostly I was looking to insulate from the motor to avoid any high frequency vibrations or harmonics. I think replacing the motor pulley will do more than these washers since that was the component out of whack.

- - - Updated - - -

Well this is perfect timing. The motor on my G4003G died Monday. After jumping through the hoops Grizzly Tech Support put me through to determine it was actually a bad motor like I had been telling them for two days they're shipping a warranty replacement.

coolidge,

I found my motor pulley out about that far as well with the key sticking out an inch or so past the face of the pulley. Also found the setscrew completely missing. That must be the screw I found floating around when I uncrated it originally and couldn't find where it went.

Have you reassembled your motor/lathe yet? If so, can you tell any difference or enough difference that it made your mod effort rewarding?

I also noticed you installed NAPA belts in lieu of the factory installed Gates. What was the reasoning behind this. I ask because I was considering going back with adjustable link belts. I used some on an Atlas I used to have and it make a noticeable difference.

AlanR,

Where did you score your specialty thru-damper bolt. That sounds very intersting. Are they still available? If so, where? I've got the rubber washers that Dog mentioned on the way from M/C as of now.

Thanks for posting guys. Great timing!

Dale

Reassembled it last night but not tested, I'll fire it up this even and report back. I took the time to align the pulleys both parallel and vertically I think that's important. Sounds like your motor was mounted just like mine, half assed. On a scale of 1 to 10 this was a 2.5 in terms of irritation, odd as it sounds I almost enjoy taking this CHINA stuff apart and improving it. I tossed the China belts on a shelf mostly because I was taking this apart and spending the time to align everything well I figured just go with some good quality made in USA belts. Hopefully I won't have to mess with this again for years. Napa had these in stock by the way, its a common size. They have a variable cog size design, wide, medium, narrow I guess to cut down on vibration. A link belt would probably be better even these are stiff, they have broke in some but still have a bit of set in them.