# Jet 1221vs wobbling bad, just sharing



## RobS (Jun 26, 2016)

So after having the Rockler Excelsior for 3 weeks, I discovered that the tail stock just had too much play and could be tightened down within 1/8" off center which would not work for drilling, so I took it back and upgraded to the jet 1221vs. I figured go big and just be done with it. The speed control is awesome. The ability to switched pulley locations was painless. I bruised my hand on the excelsior from using it non stop for 3 weeks, not an issue with the 1221.  The extra size and stability was great. The push in lock to swap thread on heads was a great touch. The tool holders are ehhh needs better spacing, but they are metal. The wrench to swap out the bolt on face was a nice touch. 

However, After one week, I've turned three pens and drilled 4 blanks.  I was loving this baby.  On the 5th blank the head started wobbling and the longer the machine runs the worse it's getting. I turned another pen but the wobble was continuing to progress and it snapped the very top off my live center.  After much searching on line for 1221vs wobble I saw a YouTube video that was exactly what I was seeing. It look like the bearings are failing.  I called Rockler they said bring it in to verify the issue is real then it would have to go to a jet service center. No exchange on this $$$$ which is a boat anchor till its fixed. So now it's time to figure how to dead lift the 135lbs. 

As a mechanical engineer I can say It's symptomatic of anything using bearings. Four possible issues: 1) bad design, improper support causing large moment arm (not the case here).  2) sizing the bearings with an inadequate safety factor (possibility, but jet is pretty legitimate so not likely).  3) random luck ended up with a bum bearing where a ball had a micro fracture that caused it to crack during the burn in phase which was my one week of mild use(possibility, this is why we did burn in on consoles at work to ensure pumps or electronics did not fail).  4) was not machined square (possibility).

So let's see how tomorrow goes when I call jet.  I could not sleep at all. I've got 12 pens on order from friends, and the blanks are already cut and drilled with brass glued in. I also ordered custom tools from Hanau here on the forum. Just bummed my new favorite tool is outta commission. 
:frown:
Thanks for listening.


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## Two Hair (Jun 26, 2016)

Sorry to hear of your lathe troubles.  I own a jet 1221 (7yrs) and so far it has been a very good lathe.  Keep us posted on how jet handles this.


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## duncsuss (Jun 26, 2016)

That's got to be frustrating -- sorry you're in that situation.



RobS said:


> Four possible issues: 1) bad design, improper support causing large moment arm (not the case here).  2) sizing the bearings with an inadequate safety factor (possibility, but jet is pretty legitimate so not likely).  3) random luck ended up with a bum bearing where a ball had a micro fracture that caused it to crack during the burn in phase which was my one week of mild use(possibility, this is why we did burn in on consoles at work to ensure pumps or electronics did not fail).  4) was not machined square (possibility).



Possibility 5) the headstock experienced blunt trauma.

Whatever the cause -- I hope they sort it out for you quickly.


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## RobS (Jun 27, 2016)

Thank you all for the empathy.

So called Jet this morning and they gave me 3 options (by the way super nice guy, non argumentative, very cordial, I even complimented him on aside from the wobble, I love this lathe it is freaking awesome):
1) Return it to Rockler (Note the Rockler I bought it from told me to call jet and they do not take them back generally, but to call them back after I spoke to Jet)
2) They can mail me out parts (min 7 business days)
3) Drop it off at a service center which is 40min from the house (time unknown, unknown if they have parts in stock could be quick could be long)

So I'm going to drive up to the closest Rockler and see if they will swap it.  Note unfortunately it is not the Rockler I bought it at which is 62 miles away from where I work, while the one closest to work is 20 miles away.

Depending on how this goes, someone will either gain or lose a customer, considering I've spent about $1,600 in 4 weeks at Rockler I assume it is in their best interest.

To be continued.


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## leehljp (Jun 27, 2016)

Rob, you are an engineer and I am not doubting your expertise at all. I will make a suggestion to a possibility - un-level floor. Even a smooth garage/shop floor may have a smooth transition from the legs area for one end of the lathe to the other end. However with a 1/8 variance that is not noticeable, that can twist or warp machinery enough to cause such problems. I remember 3 or 4 times in the past 10 years of people having trouble with table saw squareness in seemingly smooth floors. Heavy machinery will settle without being noticed, but a floor distortion of 3/32 to 1/8 inch over the space of 36 to 48 inches can and will throw thing out of kilter, and make the problem seem to be mechanical rather than foundational.


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## RobS (Jun 27, 2016)

Hank I would agree with you advice.  

However, this is on an industrial lab bench which I leveled.  Also the wobble is noticeable with nothing loaded in the spindle.  You can physically see the spindle wobbling inside the pulley housing.

RobS


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## low_48 (Jun 27, 2016)

I'm skeptical as well. How could a sealed ball bearing fail so quickly and catastrophically that the shaft wobbles? How much noise does it make? You should hear some horrible noise if the bearings have failed so dramatically. Wouldn't you need a ball to actually fall out for that to happen? Can you measure any play in the shaft? Any fore and aft motion? Any motion like the outer race of the bearing is in an oversize hole? The hand wheel threads on and sets the preload. Is it set correctly? Several of your scenarios seem unlikely unless it happened the second you turned it on. Jet has been making that lathe for quite a while, pretty hard to question their basic engineering. You didn't get a Beta test unit, there are thousands of them out there so really doubt it is a basic engineering error.


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## RobS (Jun 27, 2016)

low_48 said:


> I'm skeptical as well. How could a sealed ball bearing fail so quickly and catastrophically that the shaft wobbles? How much noise does it make? You should hear some horrible noise if the bearings have failed so dramatically. Wouldn't you need a ball to actually fall out for that to happen? Can you measure any play in the shaft? Any fore and aft motion? Any motion like the outer race of the bearing is in an oversize hole? The hand wheel threads on and sets the preload. Is it set correctly? Several of your scenarios seem unlikely unless it happened the second you turned it on. Jet has been making that lathe for quite a while, pretty hard to question their basic engineering. You didn't get a Beta test unit, there are thousands of them out there so really doubt it is a basic engineering error.



There is no noise, their is no grinding feeling.  But you can see the spindle rise and fall when it is in the housing.  Note also I did discount the majority of the scenarios.  In this case, I am leaning hard that when the casting was machined it was not machined square/plumb/on-axis.  It just so happens that one other user has had the same problem and created this video which is exactly what I am seeing:  https://www.youtube.com/watch?v=k-cG--Pauyo

It is also possible that Jet was sold some bum bearings.

I'm not discounting that this is a well matured product line, but issues do arise.  The fact that there is only one other problem like this that I could find online is a testament to Jet.


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## RobS (Jun 27, 2016)

*Resolved*

Resolved!!!!!!
The boys at Rockler figured it out.  It was not the lathes fault. The four jaw chuck had a small piece of bog wood that had worked its way into the sealing face and adapter that was causing the spinning imbalance!!!

I was wrong!!  It's not the bearings. 
Once again I was wrong and the boys at Rockler spent an hour with me trouble shooting it!!!!

Thank you. 
RobS:biggrin:


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## duncsuss (Jun 27, 2016)

RobS said:


> Resolved!!!!!!
> The boys at Rockler figured it out.  It was not the lathes fault. The four jaw chuck had a small piece of bog wood that had worked its way into the sealing face and adapter that was causing the spinning imbalance!!!
> 
> I was wrong!!  It's not the bearings.
> ...



Glad they got that resolved for you :highfive:

If you'd tested the lathe without the chuck on it, you might have reached the solution faster. I didn't think to ask you what accessories were mounted on the lathe!


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## JimB (Jun 27, 2016)

Good to hear. Don't forget to call Jet and let them know it is resolved.


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## low_48 (Jun 27, 2016)

duncsuss said:


> RobS said:
> 
> 
> > Resolved!!!!!!
> ...



In post number 6 we were told this. "Also the wobble is noticeable with nothing loaded in the spindle. You can physically see the spindle wobbling inside the pulley housing."  How did a piece of wood in the chuck show as wobble inside the pulley housing?


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## RobS (Jun 27, 2016)

low_48 said:


> duncsuss said:
> 
> 
> > RobS said:
> ...



Alright, let me break it down,
1) Looking with nothing loaded in the pulley housing, the spindle sensor collar adjacent to the optical encoder wobbles, just like on the video.

2) it wobbled with the 4 jaw chuck installed.

3) it wobbled with the pen mandrel

4) The test I did not run, but that we did run at Rockler was to load a spur center into the spindle and you will see that despite the wobble in the spindle sensor collar, the tip of the spur center does not wobble.

5) It is important to note that the spindle sensor collar wobbles like a mother but it appears to not impact the performance of the system, it does however lead one to make assumptions that impacts the ability to reach the correct conclusion.

6) Please note I never bad mouthed Jet, nor did I bad mouth Rockler.  I stuck to the facts and noted when I was guessing what the problem was.

This was a lesson learned, and wish I could change the title of this thread to "How I thought my spindle bearings had gone bad, when in fact it was debris caught in a hidden place" but I have no idea how.

Thank you all for your patience, I've run a Bridgeport lathe and mill for years and although similar there are still enough differences that make me a rookie.

I did call Jet back and did tell them we figured it out, and it was not their product, and I still love this lathe.

Also it took 3 guys at Rockler to help figure it out, the answer was not obvious.

RobS


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## low_48 (Jun 27, 2016)

6) Please note I never bad mouthed Jet,    

LOL, I can't help myself.  You didn't bad mouth them, but just suggested the possibly that they had a bad design, poor design choice of bearings, and poor machining.


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## RobS (Jun 27, 2016)

Ok, my original diagnosis was stating what can go wrong with bearings in general, please see items in blue, and my additional follow up where I say its likely not the case.

As a mechanical engineer I can say It's symptomatic of anything using bearings. Four possible issues: 1) bad design, improper support causing large moment arm (not the case here).  2) sizing the bearings with an inadequate safety factor (possibility, but jet is pretty legitimate so not likely).  3) random luck ended up with a bum bearing where a ball had a micro fracture that caused it to crack during the burn in phase which was my one week of mild use(possibility, this is why we did burn in on consoles at work to ensure pumps or electronics did not fail).  4) was not machined square (possibility).

My apologies if my wording is construed as though I was making negative remarks to Jet, I was specifically trying to say that I don't blame them and bum bearings can happen.  In this case it was 100% user error.

RobS


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## Wildman (Jun 29, 2016)

Sure glad problem resolved, other day read initial post and upset with Rockler for not exchaging lathes for you.  For whatever reason could log on but could post my displeasure with them.  Glad  message board gods kept throwing me out now and learning Rockler came thru for you!

Good luck with it!


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## RobS (Jun 29, 2016)

Yeah, officially Rockler never stated they would or would not, they said "generally and to call them back after I talked to Jet".  They also emphasized to bring it in to trouble shoot because they found it hard to believe the Jet was faulty.  They did a great job, I'm totally happy with them, I was a bit emotional that after 1 week  things started going south, which was my fault not theirs nor Jets', just my rookie a$$.  In hind sight, Rockler wanted to make sure that the machine was fully vetted before making a decision which was the right thing to do, I was just getting panicky and freaking out.

You think after using a Bridgeport mill and lathe for years you would be good on figuring out wood lathes, the truth is that they are close but not the same, their is a lot to learn and I knew just enough to get myself in trouble.

Here is the greatest irony, had I bought the 4 jaw chuck from them, I could have got the one without the adapter and I would have never had this problem but I wanted to save $50.  In the end I would have been better off buying their chuck!  I spent last night with a tooth brush and alcohol cleaning out all the threads and face of bog wood, and I locktite'd (blue) and set screwed the 4-jaw to the adapter and its spinning spot on.

Here is another thing, my drill chuck which I bought elsewhere is also spinning out of center, which I tried on other lathes and yup its messed up.  So once again, had I bought theirs instead of trying to save $15 I probably would not have had the problem.  

So in the end, me trying to save $65 ended up costing me 45 miles in driving, gas and making an ass out of myself here on the forum.

I really wish I could re-title this thread.

Greatest lesson though, was use a brand new spur center to test for wobble, if its spot on then its your accessories.

Thanks guys
RobS


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## Curly (Jun 29, 2016)

I don't think a re-title is needed, nor did you screw up. The thread will help another that has a similar issue as long as they read through all of it. I don't however think a new spur centre is the answer, but a new dead centre would be better as they are usually more accurately made. The best tool to use would have been, given your metal lathe and milling machine background,  a good indicator and magnetic base.

Glad you have the problem resolved.


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