G4003g Owners, Would Like To Compare Backlash

Bob pretty much summed it up!
Don't worry about the backlash, most all the lathes I've run had / has backlash in the carriage and the only places I've seen read discussion about it is on the net. Most people never pay any attention to it, they just use a indicator or a DRO and move on. The MTT class teaches the students to use a uses a magnet back dial indictor when using the carriage. I have the 4003g and I am satisfied with it and haven't had any problems that the others seem have had.
Either I'm lucky or I just don't pay ant attention to the little things .
Good luck and have fun with the lathe.
 
Thanks for all the replies.

This gives me more time to make chips without wondering if I should be taking things apart looking for something.

I have not notice any motor harmonics yet. Today I'll be cutting brass, I imagine it's going to show if I have a problem.
 
If you don't look go for problems and you wont find them:encourage:
If you find a problem go looking for a solution. Don't automatically blame the lathe.;)
Most problems with finishes are from types of metal / feed / speed / tool position or from the tool bit geometry ( not always but most of the time )
 
Lets have a look at the harmonic problem shall we...this first pic is at the finest feed, slowest speed 70 rpm with the thick rubber motor isolation washers removed. Wow that's ugly, its about half this bad with the rubber washers installed.



This is with the rubber washers installed, 3rd finest feed, 220 rpm.



This is at 800 rpm, finest feed and its still showing up.



Note the spiral pattern even when facing.



In testing this issue I ran at half a dozen different spindle speeds, three different feeds, light to heavy cuts, the spiraling is more severe to less severe but there on every combination. Yes I chucked up some aluminum also, same result.
 
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coolidge said:
Lets have a look at the harmonic problem shall we
Click to expand...
Coolidge, and all, Don't have a lot of info about this, but I distinctly remember reading (don't know where, but it's been about 2 years) about someone who had the exact same harmonic problem with his Grizzly. In fact your pics are what reminded me, they look similar. All he did was to put pieces of 1 1/2" thick wood planks between the feet and concrete floor, and it cured the problem. The reason I remember it so well is because that's why, when I built the feet for my Logan, I designed the 6"X 6" metal feet to also have 1 1/2" thick Redwood squares under them. Don't know if its helping my lathe or not, but I figured, at that time, with NO machining experience at all, It certainly wouldn't hurt. Quick side note to Coolidge, your casters are great--Pics coming soon ! Hope this helps, JR49
 
JR49 said:
Coolidge, and all, Don't have a lot of info about this, but I distinctly remember reading (don't know where, but it's been about 2 years) about someone who had the exact same harmonic problem with his Grizzly. In fact your pics are what reminded me, they look similar. All he did was to put pieces of 1 1/2" thick wood planks between the feet and concrete floor, and it cured the problem. The reason I remember it so well is because that's why, when I built the feet for my Logan, I designed the 6"X 6" metal feet to also have 1 1/2" thick Redwood squares under them. Don't know if its helping my lathe or not, but I figured, at that time, with NO machining experience at all, It certainly wouldn't hurt. Quick side note to Coolidge, your casters are great--Pics coming soon ! Hope this helps, JR49
Click to expand...

This problem began when I had my lathe on 1 inch thick rubber leveling feet, in fact at one point I removed them and sat the lathe on the concrete to see if that would help, no improvement. Apologies to the author of this thread we are getting way off topic so I'll wrap up with this.

Summary Findings: The issue did not exist when my lathe was new, it appeared after about 15 hours of use which in my case spanned about 18 months as I was very busy with other things and only used the lathe occasionally during this time period. It has gradually become worse with another 10 hours of use. I have tried quite a number of tests and fixes, adjusting the gibs, resetting the preload on the spindle bearings, different speeds, feeds, depths of cuts, materials, etc. The only constant in this is the motor and the drive shaft the motor connects to. I had been thinking it was a bearing issue on the drive shaft, others on the forum felt the same. But recently I came across what appears to be a definitive test performed by someone else who owns this lathe and posted pics of very similar harmonic patterns, on both OD turning and facing. This guy disconnected his motor, left it off and spun the spindle with a big drill, the harmonic pattern vanished. To confirm he left the motor disconnected, but turned it on, again ran the spindle with a big drill and the harmonic pattern returned. So it seems to be traveling from the motor into the lathe casting. Another guy installed some industrial rubber spacers between his motor and the lathe, where there is no metal to metal contact between the two, he reported this did not completely eliminate the harmonic pattern, but it was like a 95% improvement. Anyway I'm going to try a new Baldor motor as my next step at fixing this.
 
coolidge said:
This problem began when I had my lathe on 1 inch thick rubber leveling feet, in fact at one point I removed them and sat the lathe on the concrete to see if that would help, no improvement. Apologies to the author of this thread we are getting way off topic so I'll wrap up with this.

Summary Findings: The issue did not exist when my lathe was new, it appeared after about 15 hours of use which in my case spanned about 18 months as I was very busy with other things and only used the lathe occasionally during this time period. It has gradually become worse with another 10 hours of use. I have tried quite a number of tests and fixes, adjusting the gibs, resetting the preload on the spindle bearings, different speeds, feeds, depths of cuts, materials, etc. The only constant in this is the motor and the drive shaft the motor connects to. I had been thinking it was a bearing issue on the drive shaft, others on the forum felt the same. But recently I came across what appears to be a definitive test performed by someone else who owns this lathe and posted pics of very similar harmonic patterns, on both OD turning and facing. This guy disconnected his motor, left it off and spun the spindle with a big drill, the harmonic pattern vanished. To confirm he left the motor disconnected, but turned it on, again ran the spindle with a big drill and the harmonic pattern returned. So it seems to be traveling from the motor into the lathe casting. Another guy installed some industrial rubber spacers between his motor and the lathe, where there is no metal to metal contact between the two, he reported this did not completely eliminate the harmonic pattern, but it was like a 95% improvement. Anyway I'm going to try a new Baldor motor as my next step at fixing this.
Click to expand...
Coolidge, check the drive belts for smooth running or having "oscillations." Do they track smoothly and without flapping around? The "fix" you posted also would have bypassed a belt problem, and an issue due to belt problems would likely come on gradually, a motor not so much...
 
Been there done that Bob, replaced the factory belts with Napa made in USA variable spaced cog belts, replaced those with made in Europe link belts. Ran it with only 1 belt vs 2. Speaking of which, for sale a bunch of G4003G belts hardly used lol.
 
I had a very similar problem on the grizzly 9x20 lathe I had I never did figure that it was the motor. Hmm I sold it and bought another harbor freight version which was about 30 times better. May have been the motor. But I remember I changed bearings belts and messed with the lead screw but nothing ever cured it. These Chinese machines just don't have the mass to dampen it out. I do love the rumble that I hear when my pacemaker starts up.

Btw the carriage wheel on my packer has atleast .1 of backlash I've never cared to measure you should have no problem with that small amount of backlash.
 
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