***Resolved*** NEW PM-1440HVT-2 Lathe (PM fixed it)

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paynerd

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Well after saving up for many years to get my lathe, after spending $20,000+ to get it, its not working. I've been working for several weeks now with their tech support on this brand new lathe and I feel like they aren't sure what the problem is either. I know there are some pretty smart folks on here that can help us figure out what needs replaced to speed this trial and error up.

When I reach rpm speeds around 700 something starts clanking around in the headstock. My personal (VERY non-educated) guess is there is a small amount of vibration in the spindle (not being centered or damaged) and that vibration gets worse at faster speeds which causes the gears in the headstock to start vibrating.

When I sent the video they wanted me to start changing the parameters on my VDF. (Like I'd have a clue how to do that), then my tech guy said he "talked the other techs" out of messing with the VDF and to send me a sleeve that goes around the gears. No clue what he's talking about. That's where I'm at with my $20,000 purchase.

I'm assuming I'm going to have to be the guy that somehow how to figure out how to do all this repair work on my new machine. Ya, just a little frustrated to say the least. Now that I've accepted the fact that I will either have an expensive paper weight or I have to figure this out on my own. I'm asking anyone out there that can help speed this up for me. Do you think this sleeve he's talking about is the problem? What tests can I do to help figure this out.

(he had me open the headstock and make sure everything was good in there which seemed to be fine)

I uploaded the video on youtube so you can see and hear what it is. Thanks for any help you can give.




 
I agree that the spindle gear should not have any sideways movement, as you have figured out the gear is vibrating back and forth at speed. It has nothing to do with the VFD parameters. I would check with PM/QMT tech. but to me something was not assembled correctly and should be covered under warranty.
 
Are you moving that gear up and down, or side to side? From your video, it appears up and down. In either case, the fit of the gear assembly to the spindle is way too loose, you shouldn’t be able to move it in any direction that easily. The gears could have been bored too big, or the spindle could have too small OD. I think this needs to be taken apart and measurements taken to see which part is defective.
 
I agree that it LOOKS like the gear is loose on the spindle, there should be a way to confirm that without taking it apart.
 
The play in the gear is definitely alarming and is likely the source of the noise but I also wonder if the spindle bearings are not sufficiently preloaded causing the spindle to bounce around?
If you put a dial indicator on the face of the spindle, can you get any axial movement? Likewise radial movement on the side of the spindle?
I ask this because I recently rebuilt the headstock on my 12x37 and until I had sufficient preload on the spindle bearings it was unbelievably noisy, sounded like a bag of hammers falling down the stairs.
 
DavidR8 said:
The play in the gear is definitely alarming and is likely the source of the noise but I also wonder if the spindle bearings are not sufficiently preloaded causing the spindle to bounce around?
If you put a dial indicator on the face of the spindle, can you get any axial movement? Likewise radial movement on the side of the spindle?
I ask this because I recently rebuilt the headstock on my 12x37 and until I had sufficient preload on the spindle bearings it was unbelievably noisy, sounded like a bag of hammers falling down the stairs.
Click to expand...
This would be my assumption too! I sent them this video of the gear moving like that. He didn't seem to bat an eye over it so I assumed it was normal play. I will upload a video of the radial and axial movement on the spindle so you can tell me if its normal or not.
 
It’s possible the bearing preload is too loose, but if you slow the video, at the 0:45 time stamp, look at the interface of the smaller gear to the spindle, it looks like the gear is moving relative to the spindle.

I’m interested in seeing what your next video shows. It was difficult to tell from the video, is there a snap ring on the spindle to keep the gear in the proper position?
 
I assume this only occurs with the gear selector in high, there does not appear to be any chattering in the gear selector. I did have a case where the ball detente spring was not replaced in a gear selector in a 1440GT and the gear would chatter similar to what you are experiencing in vibration and noise (but more of a metal rattling). Applying some pressure to the gear selector prevented the gear movement and chatter, it also went away when we replaced the ball/spring for the detente. A bad bearing or preload, you would see some run-out with an indicator and I would expect the noise to increase with speed, this appears to be a resonant frequency at around 650-700 RPM. Does anything change if you have no chuck vs. a chuck mounted. Surprised this would not be picked up in the factory QC checks. I know quite a few people who own the same lathe and they are very smooth and have had no issues.
 

It seems to be the same if I have the chuck on or off. I just compiled a bunch of different spots to check. I think the last one has all the movement because its thin steel at that spot is my guess. I'm not sure how much movement is acceptable for this. I didn't know what a lathe was a month ago jus to give you an idea of my background on this stuff.

Let me know what other videos can help that you'd like me to upload. Thank you all for your help on this!
 
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