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New Jet Lathe - Grinding/Clicking Noise

5K views 47 replies 11 participants last post by  builtinbkyn 
#1 · (Edited by Moderator)
So yesterday I finally fired up my new Jet 1221. With nothing mounted but the faceplate, I expected to hear a cool whirl and humming sound. Unfortunately that wasn't the case. There was a noticeable grinding noise accompanied by an intermittent clicking or knocking. The machine on slow speed ran silently until the speed was increased.

So with some tools in hand I went about trouble shooting it myself. Removed the faceplate and live center, thinking maybe one of them were not seated right. Then I pulled the handled. Still the same noises. I then moved the belt to another speed setting and still the same. To my ear, it sounds like bad bearings.

Next step was a call to Jet. The tech, after hearing the noise thru the phone, had me go thru the same paces I had already done as the noise wasn't usual. He then had me pull the belt and run just the motor. No noise was heard. He also had me loosen and tighten the set screws on the pulley in specific order- keyway first followed by the opposite side. Still the noise persisted. He informed me that since I purchased the lathe thru Amazon I would have to deal with them if this was in the first 30 days. However he did tell me that once a second call was placed, they would deal with it. That made me feel a bit more confident Jet wouldn't just make the claim that since it's spinning true and working, the noise is incidental.

I'm pretty confident a bearing or even both bearings are the culprit. I pulled the shaft and even though they don't make the grinding noise when spun by hand, the belt tension could surely influence this situation if the bearings were faulty.

This is a pretty basic design. Nothing complicated about it. What I'd like to do is replace the bearings with higher quality bearings rather than wait the 30 days and then make the second call to Jet. I know it's additional expense, but it's also my time and heck, if the bearings they're using aren't all that great - I believe they're NSK - sizes are 20×42x12 -NSK #6004vv and 25×47x12 - NSK #6005vv. Not being familiar with bearings, is there a better type of sealed bearing for this? Cylindrical bearings vs the ballbearings used? I suspect Jet went middle of the road and would actually prefer better if available.
 
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#3 · (Edited by Moderator)
Those are pretty standard radial deep groove ball bearings… If you really want to replace them, give Lynne a call at Accurate and she will hook you up. Although, NSK are generally pretty good bearings, and it would be very unusual to have new ones that were bad. If they are sealed (not shielded), it's pretty easy to remove the seal and inspect the balls, cage and condition of the grease to see if they are good (you can't tell just by spinning them).

I personally would let Amazon/Jet fix the problem since it's a new machine.

Cheers,
Brad
 
#5 ·
Thanks for the responses guys. I guess I may first try to deal with Amazon on this and see if they'll replace it. Packing this up and getting it shipped will be a hassle, but may be the route I should go. I guess I'll base my decision on the logistics - hopefully Amazon will provide a pickup vs me having to take it to a shipping center. I hope I don't get another with the same issue. Actually regarding the issue, am I expecting too much? I thought it would run pretty silently except some noise from the belt.
 
#6 ·
Amazon has fantastic customer service. When I returned a lathe they gave me a shipping label and arranged for UPS to pick up the box. But I had to buy a 2nd lathe and wait for a refund on the first lathe when they received it in Kentucky. If you bought from CPO through Amazon, CPO will ship a replacement as soon as they get confirmation by UPS that you shipped the bad one but you'll need to call them to make that happen.

As for bearings, NSK is a premium bearing. It's weird that you got bad bearings in a new lathe. This wasn't a warehouse deal by any chance?
 
#7 ·
Amazon has fantastic customer service. When I returned a lathe they gave me a shipping label and arranged for UPS to pick up the box. But I had to buy a 2nd lathe and wait for a refund on the first lathe when they received it in Kentucky. If you bought from CPO through Amazon, CPO will ship a replacement as soon as they get confirmation by UPS that you shipped the bad one but you ll need to call them to make that happen.

As for bearings, NSK is a premium bearing. It s weird that you got bad bearings in a new lathe. This wasn t a warehouse deal by any chance?

- Rick M
Hey Rick. The lathe was sold and shipped by Amazon according to the description on my order. I don't know. Maybe I'm expecting the machine to run differently than it's capable of. It turns true, but I didn't expect it to sound the way it does. The tech even commented it shouldn't sound as it does when hearing it thru a cell phone. If it's the bearings, I can replace them easier than shipping the darn thing back and then waiting on a replacement. There's no issue with the motor and everything else is fine. The electronics work and the speed readout seems to be accurate for the pulley setting. A bearing change is the easiest route. They're $15 each. At this point I'll wait the 30 days and then see what Jet has to say. In the meantime I'll use it as the tech said I should do. If there's any significant issues, they will reveal themselves during use.
 
#11 · (Edited by Moderator)
$15 is nothing for quality bearings. I would be suspicious if they were less, especially something uncommon like VV.
- Rick M
6000 series = Extra light duty metric
VV = double non-contact seal (one each side)

Nothing really uncommon about them.

Cheers,
Brad

PS: The 'non-contact' seals are really unnecessary IMO, given the low speed of a lathe. The max speed for the VV's is ~20,000rpm, the contact seals (2RS) are a few thousand less. The max spindle speed of that Jet lathe is 3,600rpm :)
 
#12 ·
Yeah I did see similarly spec'd bearings for about a 3rd of the price. I was actually interested in getting better bearings than the OEM bearings. I was wondering if they need to be deep groove bearings or if cylindrical bearings were suitable. Aren't they supposed to be better? I have no knowledge of this :)
 
#13 ·
IMO, you should just go with what it was designed with… cylindrical roller bearings are designed for radial loads, not axial. The deep groove bearings that were in there are designed to handle both radial and axial loads.

Cheers,
Brad
 
#14 ·
OK thanks Brad. One thing I'm going to do before anything else is to pull the shaft, remove the bearings and inspect them and the recess each seat. The casting may have some flash or something that's preventing one of them from seating properly. My suspicion would be the one on the work side. The retainer for that bearing is a metal flange that bolts to the housing. If the bearing isn't seating all the way in or of it's skewed somewhat, it could be causing the sound I'm hearing. The motor without the load of the tensioned belt, spins silently. I don't suspect the motor in any way. It has to be something else.

The other thing that could be causing this is the collar for the speed sensor. It's rather poorly executed. It's a machined aluminum collar that slides over the shaft and is retained with one set screw. Inside the collar is a magnet that's retained with a c-clip. It has a shoulder on only one side to bear on the shaft. The other side, where the magnet is retained with the c-clip, has no support on the shaft - if that makes sense. I checked to ensure it wasn't hitting the pulley housing and it wasn't. However now that I think about it, it could still be the culprit. Centrifugal force could actually be causing the magnet spin inside the aluminum collar. That would sound like a bad bearing. An easy fix would be some CA glue inside between the magnet and the collar.
 
#16 · (Edited by Moderator)
This is the kind of stuff I do to old lathes, I sure as hell would never accept a new lathe that needed that much work without a significant discount.
- Rick M
+1

If you were willing to do the work, you could have saved a significant amount of money buying used. Given that it's new and never been used, have them make it right. You have waited this long before ever getting a lathe, so a few more days isn't going to kill you :)

Sort of related - My PM45 has a slight clicking/clanking noise at certain speeds. Turns out the index wheel has loosened up where the cutout for the keyway is, which is letting it move around a bit - and is apparently the one common problem those lathes have. I have just ignored it, as it doesn't effect the operation of the machine in the least. But I have a new drive belt on order, as the one on there now is showing it's age and has a couple of 'cogs' that have gone missing. I plan on welding it to the stop collar that sits behind it when I go to replace the belt, since I will have to pull the spindle anyway. Stuff like that can be expected on a machine that is over 30 years old… but I would have been pretty upset had it been a brand new one that I paid top dollar for!

Cheers,
Brad
 
#17 ·
I can't agree more with the both of you and why I did buy new. However, when I called Jet, the tech had me troubleshoot it too. So go figure LOL Actually pulling these bits out of the lathe takes about 3 minutes. So I'm not really spending much time on it. If I don't find the cause of the grinding noise, it goes back for a new one.

I remember when I was looking at cabinet saws. Posted the usual thread on it too :) Many responses said to get a used one. I replied, I didn't need a project like that. LOL I also remember during my search, seeing how many Grizzly customers on new saws went thru similar instances where they were required to either replace pieces sent to them by Grizzly and/or pack the darn thing up, ship it back and await a new one. Well at least this machine doesn't weigh 500lbs ;)
 
#18 ·
Loose set screws will cause a ticking sound. It's a long way from grinding sounds but it only takes a second to check and seems more likely than a bad bearing. Might also check the motor mount, loose bolts cause bad sounds.
 
#26 ·
Well there's good and bad in this. The tech also seems to think it's the bearings. I need to take it to a service center :( Not happy about having to lug a new machine there and then wait for it to be repaired. I asked if they could send me bearings, but he said the service center was the only option presented to him. I may just pick up the bearings and do this myself. My time is valuable to me. Though the center is about a mile or so from me, taking it there, waiting for them to get it repaired and then retrieving it may not be worth the $30 for the pair of bearings. I guess I call the service center first to see what the turn around time is and if they have parking lol
 
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