Thread chatter on Grizzly 4003G resolved...finally..!!!

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eww1350

Guest
I wanted to post this on the open forum just in case there are other 13x36-40" Chi-Com lathe owners out there that are having the problems I had with chatter when making threads...I solved the problem..MYSELF...and am willing to share my fix with others...and because I recieved NO help from the manufacturer I am not going to describe the fix here...but anyone willing to contact me (send a PM)...I will gladly share this resolution...it is NOT expensive and can be done in a couple of hours...it has been frustrating working thru the problem and I don't want others feeling as though they will just have to live with it...:mad:


Eddie in Texas
 
NO...it has nothing to do with the spindle or loose parts, or tooling, or set-up...
 
I am surprised by the number of people that are sending me PMs stating that they have a Grizzly with the same chatter problems...where were you guys when I was getting denounced and told that It was me being incapable of setting up a lathe properly..!!!
If more had come forward on this open forum I think Grizzly would have taken this more seriously...and not swept it under the rug as operator error...!
 
I've had a Grizzly lathe for several years that has served me well. But I've got a couple buddies that had the same issue as you've had. Like you, they had no luck getting Grizzly to help them resolve the problem in any way. Both lathes were eventually returned and both went on to purchase machines from different supply houses. I've been happy with the stuff I've purchased from Grizzly, for the most part. But I doubt I would buy another big ticket item from them simply due to their lack of technical support.
 
Ok...OK...I have had Sooo many guys saying "I or someone I know has the same problem" ..I can't keep up with all of the requests...over 50 so far..!!!
I am going to take some photos and post it on the open forum...Give me a couple of days to get it up...I am going to have to dissassemble some of the lathe to get photos of my fix...
I empathize with those who are living with the problem...I was about 24 hours away from buying all the hardware needed to convert to 3-phase..but I am too hard headed to believe that a single phase system cannot work on a lathe...
Keep in mind I went after this on a Saturday morning with what material I had in my modest home shop just to see if my theory was correct...I am a low budget..use your head type "fix it" guy...and I will put hours, days and weeks into analyzing a problem..before doing any wholesale changes...anyone that knows me knows that I am somewhat of a "perfectionist" (within my abilities)...and I will do for another exactly as I would do for myself...just because that is the way I was taught...

Anyway stay tuned for the rest of the story...

Eddie in Texas
 
Here we go...I took some photos and put them in TinyPics.com...I will paste them in and see how it turns out...

Here is the basic concept;
Using a quality ribbed/corrigated type anti-vibration pad about 4"x4"..(bought it on Ebay) and some SuperFeet...(only thing I had in the shop that was neoprene faced)...I installed the AV material between the motor mount/bracket and the lathe frame.
I removed and replaced the hard washers on the 3 mounting bolts with the superfeet...and adjusted motor belt tension to the minimum that would still pull without slipping...isolating the harmonic "buzz' coming from the motor..
Grizzly mounts the motor on rubber/polyurethane pads..but they are too hard to absorb the vibration...It is IMPERATIVE that the anti-vibration pad and the soft washers NOT be compressed...use light torque on the bolts (about 20-30 ft.lbs)...the motor will not slip or move when it is turned on-off or run at high speed...let the AV material absorb the vibration...if you over tighten or compress the material you will defeat its purpose...

Photo of the lathe motor mount with AV material in place...
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Photo of factory installed rubber pad...way too hard to do any good..!
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Photo of anti-vibration material and superfeet used...
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Make sure you remove these hard washers and use a soft face washer or you will be tempted to over torque the mounting bolts
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Thread with chatter before the "fix"
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Before and after results of threads cut at 70 rpm with a CARBIDE threading tool...
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Hope this is of help to others...if there is something I missed...let me know...
my lathe is much quieter now and is making threads like it was supposed to...:)

Eddie in Texas
 
Thank you very much for posting that.

I think it explains why all my thread chatter problems, and some related turning problems, went away when my single phase motor died and I converted to three phase. My lathe isn't a Grizzly, but it is a 12 x 36 gear head, and it does everything better with a three phase motor. Three phase motors do not have the torsional torque pulsations that a single phase motor has.

Fitch
 
eww1355
Thank you so much for resolving this issue. I certainly hope that I, and the others who will try his method, will be as successful as you have been.

The comment from Shiraz Balolia in an earlier thread that there were “only a handful of issues, some caused by lack of knowledge”, was a statement that turns out to be wrong. A question for him will be “what are you going to do with this information?”.

I have had this thread chatter problem from day one. I feel relieved to learn that it is not my technique. I will soon attempt an upgrade of the motor mounting system.
 
EWW1355
Thanks again for the information. As soon as the pads arrive I will fix my lathe also. Great pictures by the way. The entire mods will cost me about $20, you would think grizzly would find it worth their while to implement this into their machines and improve their customer relations above where it is now. I guess sometimes when people get to busy making money they forget about the people behind the money they are taking. A simple mod like this wouldn't cost them squat and put them ahead of their competition by leaps and bounds. Anyway we thank you and appreciate it.very much.
 
On my Jet 12 X 36 BD, I converted to 90V dc drive motor, but is still had a very minor amount of vibration in a fine cut. I replaced the belts with "Linked V Belts and it not only ran MUCH quieter, the vibration marks in the cut were totally gone. I was going to remove the motor from the lathe and mount it on the wall behind the machine to remove the vibration. A few $$ at Habor Freight saved me from doing this.........

linkvbelt_055-vi.jpg
 
Take off the outer drive belt and pitch it, before you get extreme....it's apparent in your photos that the belts are not matched or in proper tension.
Dual V-belts are nothing but trouble. It's almost impossible to get them to not chatter.
 
TRA said:
Take off the outer drive belt and pitch it, before you get extreme....it's apparent in your photos that the belts are not matched or in proper tension.
Dual V-belts are nothing but trouble. It's almost impossible to get them to not chatter.
Click to expand...

Good idea...I will also try that just to make it as smooth as possible...

Thanks

Eddie in Texas
 
Thread chatter on Grizzly G4003G

I'm just one more person who has been frustrated with the poor quality of threads I was able to cut on this machine. The modification posted by "eww 1350" made a huge difference. The only thing I did diffenently was to make a set of the square rubber spacers between the motor and the cast bracket that the motor attatches to, out of the same anti-vibration material. The hss threading inserts from Arthur R Warner Co. are additionally the best I have used.
Thanks so much for sharring.

Hugh Fraser
 
I had a similar problem with my Taiwan Jet lathe (Chattering when threading in back gear). I did the same thing to my motor with little improvement. I took the motor off and had it rebuilt with all new bearings and had rotor balanced. Its really amazing the difference in the quality of threading, turning and facing even improved, Not to mention the reduction in noise and motor vibration. Took me 4 years but I have a keeper lathe now.
 
I have removed my motor and motor mount in preparation to install the anti-vibration pads. I gave the motor a spin and it sounded like a wrench sliding down a steel incline. That is right, the bearings are toast.

This lathe is 29 months old. I noticed the noise a couple of months ago, and it kept getting louder. I thought it might be the spindle bearings and have not had time to check them. I now know where the sound was coming from. My thread chatter has been there since day one.

I picked up two different kinds of anti-vibration pad, and some longer hex bolts to compensate for the added thickness. Check out the heavy duty sandwich of anti-vibration pad over a cork center.

I made some neoprene washers for the bolts. I already had some sheets of neoprene, but I am not sure how I am going to configure everything yet.

I took the motor to an electric motor repair business with instructions to replace the bearings, and dip and bake the motor because of the bad things I have heard about Chinese motors.
AntiVibrationPad.jpg
 
I haven't had the issue out of my Shop Fox M1112 lathe which is suppose to be manufactured at the same facility with the same specs as the Grizzly G4003G lathe. Here are some pics I took of a recent Remington thread I did. I don't think I can see a lot of chatter in the threads, but then I'm not a career machinist with multiple years experience.

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