# Jet 1642 motor gone bad



## Underdog (Oct 29, 2012)

Welp. It finally happened. I was turning some coffee table legs this weekend and the noisy motor got a LOT noisier. Time to do something about it.

I have a Jet EVS1642 that I bought new May of 2009. And unfortunately, it's past the 5 year warranty date. By the time I noticed the noise, last year, it was already out of warranty. Darn.

The new motor is right at $460 and then there's shipping. I called the local motor rebuilders, and their take is that it's cheaper to buy the new motor than to rebuild this one.

I took the motor out and clamped it to my bench and tried to get it to make noise or wobble like it's been doing under power, but it seems smooth as silk. Probably what's happened is the rear motor housing has gotten wallowed out… and only when it's under power does it give way.

Those table legs aren't going to pay for this… Sigh.

Why's a motor going bad on a 6 year old machine anyway? Not like I run the dog crap out of it running it a couple times a month….


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## exelectrician (Oct 3, 2011)

Hmm, perusing the parts manual on pages 25 through 29 I came to the following conclusion the motor is a three phase unit (very robust usually) the problem is probably in the inverter unit (part # 64) Here is what I would do,
1. Do this check with the power off, spin the motor by hand and listen for any roughness, It should spin freely and quietly. If this test reveals a quiet motor then the problem lies elsewhere.
2. Check the lathe spindle and the pulleys, also check for missing teeth in the drive belt, If these parts are all okay, then the problem is most probably in the inverter unit.

Let us all know how your tests go, good luck.


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## Underdog (Oct 29, 2012)

Thanks for the tips, but there's no way it's the inverter. The inverter won't cause the motor shaft to wobble. It's definitely the motor.


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## MrUnix (May 18, 2012)

Making noise and motor shaft wobble sure sounds like bearings. I would open it up and check before writing the motor off completely. If you have already resigned yourself to buying a new one, it can't hurt any. I'd also be suspicious of any motor shop that made such a claim over the phone without actually seeing the motor in person, but that's just me 

Cheers,
Brad


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## exelectrician (Oct 3, 2011)

Oh, the shaft wobbles? Is the shaft bent? Most good motor shops could replace the shaft. But if it is just the bearings then it is a simple job to change the bearings, there are many good YouTube videos showing you what to do for three phase motors, not expensive at all, so good news, you should be up and running soon.
Or a replacement motor from Baldor through Global here: #VM3554T $341.95 
http://www.globalindustrial.com/g/motors/ac-motors-2-phase/3-phase-general-purpose-motors/general-purpose-3-phase-200-and-575-volt-motors-103643


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## bigblockyeti (Sep 9, 2013)

Unless it's a proprietary motor, used three phase units can usually be had very inexpensively. What is the motor frame size as listed on the nameplate?


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## Underdog (Oct 29, 2012)

Yeah. Bent shaft. The weird thing is that the pulley doesn't wobble UNTIL it's under power. Just spinning it by hand won't make it wobble or scrape. Smooth as silk.
The magnetic force has to be pulling it to one side.

I pulled it apart last night and got a look. The armature is scraping the stationary coil laminations and popped quite a few out of place. The armature is loping, or jumping rope. The bearings are still in good shape, and the end caps aren't wallowed out. So basically the shaft has gotten bent somehow.

HOW? I have no friggin idea. This thing has been in my shop for the last 6 years and used probably on average a couple times a month. Never transported anywhere except when bringing it home the first time. Never been dropped or hammered on. Never had the motor off, never had changed the belt even…

Here are some pix.
Here's the tag:









You see where the armature has been scrubbing on one side. I mounted this between the 60 precision centers on the lathe, and turned it by hand. You can see it loping, even though the ends of the shaft don't really move much.








If you look close you can see where the armature hit the laminations and has pushed several out of place:


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## Underdog (Oct 29, 2012)

As for the replacement Baldor motor, there's a great thought. I'm all for spending less money if the quality is at least the same, and it will actually replace this one. If the quality is better, and I mean that the shaft won't bend under normal use, then so much the better.


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## WoodNSawdust (Mar 7, 2015)

Baldor is a well know manufacturer of quality motors. I would not hesitate to use one as a replacement.


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## MrRon (Jul 9, 2009)

> Baldor is a well know manufacturer of quality motors. I would not hesitate to use one as a replacement.
> 
> - WoodNSawdust


Some Baldor motors are now made in China. Check out this site for 3 phase motors: https://www.surpluscenter.com.


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## MrUnix (May 18, 2012)

You will be hard pressed to find a better motor than a Baldor. Absolutely better quality than that made in Taiwan thing you have now! However, I find it hard to believe that the armature could be bent from use, as they are pretty stout and would require quite a bit of force to damage. If it really is, then it most likely had to have been that way since it left the manufacturer. But, the damage you see looks exactly like what happens when bearings start to fail. It might be entirely possible that cleaning up the worn areas a bit and replacing the bearings could be a cheaper alternative than a motor replacement. Even though the bearings 'look' good, they can be worn enough to allow enough lateral movement under power to cause the contact damage you have. Would cost less than $20 to test that theory 

Cheers,
Brad


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## bigblockyeti (Sep 9, 2013)

I hate it when they don't list the frame size so everything has to be reverse engineered to end up with a quality product instead of just making something worth a darn in the first place. $460 for a motor that doesn't even have a frame size listed is about $459 too much. I bought a brand new 6 pole 3 phase Toshiba motor for my drill press to be used with a VFD. I think I paid $40 from a local industrial surplus center. I looked up the MSRP and it was just under $1100. That might be a thought, surpluscenter.com is basically the same, only everything is online and shipping can get steep pretty quick with something that weighs as much as a motor. Looking at the parts list online, it really looks like a 56C frame which is fairly ubiquitous and even brand new for a quality motor shouldn't be over $300. Do you have shaft, key and mounting bolt diameter and pitch dimensions? Those could indicate if it actually is a standard frame size.


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## Underdog (Oct 29, 2012)

No, I'd have to measure all that.

And NO the bearings are NOT bad. I'd know. I've replaced enough as a mechanic and maintenance man to know what a bad bearing is like. For them to be bad enough for this much movement in the pulley, and those bearings would be absolutely grinding… And they aren't. They don't even make any noise when you spin them by hand. No roughness, no noise. Smooth as silk…

I mean come on. If I can SEE the lope in the armature when the shaft is mounted between centers and rotated by hand, and the bearings are totally out of the picture, what makes anyone think that it could be bearings? I don't even have to measure the runout in that armature to see that it's past the point that bearings would fix it.

Don't you think I'd jump at it if it could be fixed that easily?


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## MrUnix (May 18, 2012)

> Don t you think I d jump at it if it could be fixed that easily?


Was just a suggestion 

And was based on rebuilding a lot of motors that had the exact same damage. The fact that the noise progressively got worse over time and use, combined with the damage seen, was what prompted it. Bearings can go bad without showing any indication or making any noise. A worn bearing still full of grease will appear perfect until loaded up.

Again, it was just a random thought thrown out there for consideration… feel free to ignore it 
I guess your next move is to try and find a suitable replacement… bummer.



> I mean come on. If I can SEE the lope in the armature when the shaft is mounted between centers and rotated by hand, and the bearings are totally out of the picture, what makes anyone think that it could be bearings? I don t even have to measure the runout in that armature to see that it s past the point that bearings would fix it.


Another random thought - spinning it between centers might not prove anything. The critical area is between the bearings, and the shaft end past the bearings may have runout that won't cause clearance problems between the windings/armature. It would cause uneven wear in the bearing on one side though. Just saying.

Cheers,
Brad


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## Underdog (Oct 29, 2012)

I'll humor you and double check those bearings… Perhaps you're right. But I've been doing some perusing of the internet, and apparently Jet had a bad batch of these motors. I just haven't used it enough for it to show up until now.
Gonna lobby for help with Jet customer service…


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## TheDane (May 15, 2008)

> Gonna lobby for help with Jet customer service…


That sure won't hurt … they may cut you some slack since it is a evidently a problem they have run into before. I had a problem with my new Jet bandsaw several years ago … not only did they come up with a solution, they sent me a free set of clamps for my trouble.


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## Wildwood (Jul 22, 2012)

Sorry to hear having motor trouble with your Jet 1642. I have the same lathe but 110V version. Thought had a solution to your problem and perhaps just changing out on/off switch might work for you! Long story short replacing my on/off switch solved my problem!

Now that you have the motor off and disassembled could you just shop electric motor stores in your area? 
Hope all goes well please keep us up-todate on how you make out!


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## Underdog (Oct 29, 2012)

Was told yesterday that this problem after 7 years (it's actually only 6 years) wasn't a manufacturing defect, but normal wear and tear, and would not be covered under any kind of warranty.

Normal wear and tear. Yeah right. And I'm a martian.

If I can expect that a new motor will only last 6 years before the shaft bends under light duty, what's that say about the quality of the product? Why should I buy an OEM?

I bought a set of bearings that turned out to be only $4, so we'll see if that fixes it. I doubt it, but it's worth a try…


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## TheDane (May 15, 2008)

> I bought a set of bearings that turned out to be only $4, so we ll see if that fixes it. I doubt it, but it s worth a try…


Let us know how this works out … a couple of close friends in my turning club have Jet 1642 lathes that would be about the same age as yours.


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## wormil (Nov 19, 2011)

Bending a 5/8" steel shaft is not trivial and is something you would notice when it happened, not normal wear and tear.


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## Wildwood (Jul 22, 2012)

Since own the same lathe really interested whenever a problem with them pops up. Too bad don't know price of Rikon 70-305 (1 ½ HP) motor which runs on 220V they don't list price guess have to call tech support 877-884-5167. The Rikon owner's manual almost exact copy of Jet! Might be able to shame Jet into giving you a break on price of a new motor. Squeaky wheel always get greased!

Asian motor HP ratings have always been optimistic. At one time Jet 110V & 220V lathe had a 1 ½ HP motor. 
Not sure when Jet bumped up that motor to 2 HP just know it has been awhile. 
Couple of people posted positive experiences on different message boards several years ago. Could not find an address online for a Jet service center so have to call tech support which troubles me. Think read one or two reviews at Amazon.com where people had bad experience shipping their 1221 lathe a service center and not happy with service.

At one time if lived near a jet service center could get a break on parts if brought lathe or part to them.

Any way wish you the best of luck dealing with Jet!


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## Underdog (Oct 29, 2012)

Put the new bearings in the motor last night and ran it up. There's still a noise there at slow RPM, and the shaft/pulley is still wobbling. So that didn't fix it.

Taking the motor to the motor shop today to see if it can be matched up with something aftermarket, so I can have price and availability in hand before I call Jet Customer Service.

They have no legal obligation to do anything at all for me, but blowing me off with the "normal wear and tear" line isn't going to keep me as a customer. If a bent shaft is what happens under normal wear and tear, then I'd hate to see what happens under severe service conditions.
And I have no desire to buy more of the same…


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## TheDane (May 15, 2008)

> And I have no desire to buy more of the same…


Can't say that I blame you for that. Good luck at the motor shop.


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## smitdog (Aug 20, 2012)

From a mechanical engineer's perspective - I'd guess the shaft has been bent since the beginning and it's just taken this much time to get worse because of the light use. Your jump rope analogy is pretty good. If it was bent even just a little bit to begin with, then the center of mass is going to be off from the center of rotation and will get pulled out due to the centripetal force. Think merry-go-round and sitting right in the center vs. sitting a little off center and getting pulled to the outside. That force gets higher as the RPMs increase so at those really high speeds it's applying more force out away from the center making the metal bend more than what you can generate by hand. Add to that Force + Time = Fatigue so as the metal fatigues it becomes easier to bend. As the fatigue gets worse, the metal bends more and the center of mass moves further away from the center of rotation which makes the force higher which makes the fatigue worse which… You get the picture, right? Sounds to me like you've just recently accumulated enough time that the metal of the shaft has fatigued enough and the force at high RPM is warping the shaft enough that the armature is finally hitting the surrounding coil.

What stinks about warranties is that they don't care about actual hours on the machine which would be a truer representation of manufacturers error. They definitely favor those that use their equipment every day…


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## bigblockyeti (Sep 9, 2013)

This experience of yours has been enlightening for me & if JET continues to choose not to stand behind their product for a very obvious manufacturing defect they will never receive any of my business!


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## Underdog (Oct 29, 2012)

SmitDog,
That was generally my thinking about this scenario, but you've detailed it well enough to make it even more plausible. What makes that scenario even more plausible is the fact the machinist didn't even bother to chuck up the hot roll stock (yup, the scale is still on the shaft) halfway true, before turning it for the pulleys, bearings, and armature core. The unturned hot roll portion lopes like a crankshaft journal… I was taught in machine shop class to always true up your stock in your adjustable jaw chuck until it registered very little or no runout. Obviously this "machinist" didn't do that.

Unfortunately the motor shop is saying that the mounting is all proprietary and stuff so they can't really help me. I'm asking them to reevaluate and see if there's any way I could just drill new holes in my mounting plate for a different motor. I have a feeling they just don't want to mess with it. Can't blame 'em really, since they're currently in the middle of a rush job on a 600 HP motor rewind…


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## MrUnix (May 18, 2012)

> Put the new bearings in the motor last night and ran it up. There s still a noise there at slow RPM, and the shaft/pulley is still wobbling. So that didn t fix it.


Well that sucks! Was hoping it would be a cheap fix for you with the bearings. I really dislike machines with proprietary designed parts and electronics for the reasons you have already mentioned. It makes maintenance and repair years down the road either really expensive or impossible. They may provide some nifty wiz-bang features, but longevity suffers as a result.

Cheers,
Brad

PS: That's one reason I refuse to give up my vintage Delta lathe with stepped pulleys and a generic induction motor!


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## Underdog (Oct 29, 2012)

MMMMmmmmmmmm….. that Crow sure tastes good. A bit chewy though…

Just dropped the motor off at the motor shop. They were kind enough to give me 15 minutes or so. Took the end caps off and inspected. Asked what was the reason I took it apart in the first place - bearings gone bad?

I said, no, the armature was hitting the coil laminations, and I replaced the bearings just in case that was the problem. But it didn't fix it, because, I said, the shaft is bent.

He says, well sometimes the belt gets tightened too tight, and then the bearings act as a fulcrum and the tension pulls the pulley end away from the bearing, and the center of the shaft bends away from that tension. He says, I can just about tell you which direction the tension is being pulled from where the armature is hitting the coil laminations. And when we pulled it back apart, sure enough, the armature was hitting just about the predicted spot.

The upshot is that he took pity on me and was going to bend the shaft back to true, and trim a bit off with the lathe to make sure it didn't hit anymore - for less than $100.

And the replacement motor option is kinda dead in the water. The motor mounting was different, a C-face needs a recess to mount in, plus the bolt pattern was different and the clincher was the 5/8" shaft being smaller than a 16mm shaft…

I trust these folks. I've been dealing with them for years and years, and they've ALWAYS treated me right even when it would have been easy to take advantage. And they do a LOT of business with some REALLY big industry folks here. (They've got a couple of 700 HP motor jobs after they finish the 600 HP job, right this minute.)

So, I'll take their word for it, apparently I did cause the problem. I admit, I was too quick to blame Jet for it.

Mmmmmmm….. Crow. Jest eat it….


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## bigblockyeti (Sep 9, 2013)

If they have specified a motor with a shaft that can be bent so easily, still their fault. Root cause analysis based on what information you've given thus far proves this. JET used to be a good Taiwanese copier of quality US built machines, that is clearly no longer the case.


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## Underdog (Oct 29, 2012)

I would have said you were right, but this guy rebuilds motors for a living (he's been building motors for longer than 30 years), and he knows what he's talking about. He's seen it even on 300 HP motors.

He also said the scale and eccentricity on the hot rolled shaft is no big deal, because they balance it afterward anyway. Also, the don't heat treat the shaft because it would break. It has to be shaft steel, but it's not hardened because it has to have some flexibility in it.

So… I'm just gonna go with I tightened the belts too tight and never do it again…. Gonna break out the manual and see what it says in there about belt tension.


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## Wildwood (Jul 22, 2012)

Learned a lot reading this thread and happy to hear problem solved. Good luck with almost new lathe!


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## Underdog (Oct 29, 2012)

Well. I wish I could say that the problem has been solved. But having the shaft straightened and the rotor turned to have some of the diameter taken off, has not fixed the problem.

In fact I'm not sure it's improved it very much. It's still making the same noise under power that it did before, and the pulley wobbles almost as much as it did before.

I'm just trying to find out exactly what is going on, by following the evidence. My theory is reverting back to my original one at this point, and I'm spitting that crow out…

Here's a closeup video of the pulleys under power. The "scrape, scrape" noise happens only under power (with or without the belt on) and when it's turned by hand (the very end of the video) it's perfectly smooth and quiet (except for the rattle-clack of the chuck jaws I forgot to take off.)


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## bigblockyeti (Sep 9, 2013)

It does still look like the shaft has a little run out in the video. Did the motor shop have the shaft supported between two centers or was it supported on the output side where the bearing is located? I only ask because it may look better from a runout standpoint when supported differently when in service than when being machined/balanced. Is the stator still tight in the case? I've seen instances where everything is smooth and quiet when not under power and when under power, the magnetic field causes the stator to move very slightly inside the case allowing contact with the rotor that can sound like a constant rubbing or slight rubbing every rotation of the rotor.


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## JoeinGa (Nov 26, 2012)

You CAN see that the wobble is very pronounced. I see you have the belt on the inner pulleys. Just curious .. is the wobble worse when the belt is on the outer pulleys?


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## Wildwood (Jul 22, 2012)

Real sorry lathe still not fixed. Have no idea what to tell you other than consider e-mailing Jet tools and include that video? Maybe they will spot something and help you back up to speed besides trying to sell you a new motor.

Best of luck about all can add!


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## Redoak49 (Dec 15, 2012)

Sorry it is not fixed.

I might take the belt off and put a dial indicator on the shaft. Also, do it with belt on and check the part being driven by the pulley. I would think that with a dial indicator you can determine where the problem is.

Good Luck


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## jimintroy (May 4, 2019)

Hi Underdog. I know this is a few years out but my Jet 1482 motor is exhibiting the same issues you saw with yours. I began to hear a low clunking noise last year and it has gotten progressively worse. I replaced the bearings but it had no effect on the noise. Not knowing exactly where the noise was coming from I continued to use it figuring the problem would better present itself with time. Well, it has. Yesterday I noted the usual clunking noise but also that the motor had lost its umph and was hot to the touch. So when I open it up I expect I'll see damage to the windings, etc.

In this discussion there was talk of locating a cheaper third party option. Were you ever able to get anything to fit?

Thanks,

Jim


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## jimintroy (May 4, 2019)

So I just pulled the motor apart for the fifth or so time, fully expecting there to be a mess. But the core was clean as was the armature. When I first tackled the problem a month ago, I noted that the motor shaft had some play on the pulley end in the radial direction. I thought "Ah-ha! That's what's causing my troubles." So I replaced both motor bearings. But soon (if not immediately) I was back with same clunking noise. This is a noise that occurs at all speeds and both directions. If I let up entirely on the belt tension it goes away and if I crank the tension up is lessens a bit, but just under the weight of the motor it clunks quite a bit. So I tried yet another front (pully-end) bearing from a different source, as I noted it had that same radial play as before. Today I noted that the play was there in the second replacement bearing.

I put a dial indicator on the shaft and measured the runout on both sides of the front and back bearings. There does seem to be some runout, with the worst being about 0.015" on the core side of the back bearing. Mind you, I mounted the thing between centers and I can't vouch for the accuracy of the spin. Anyway, here's what I get:

rear-check1-bearing-check2-core-check3-bearing-check4-front
0.004" 0.015" 0.007" 0.007"

I created a google album with dial indicator videos and some photos of the core and armature.

https://photos.app.goo.gl/pdvEHS8sXDM232V78

Any advice or observations appreciated.

-Jim


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## TopamaxSurvivor (May 2, 2008)

Not much in there to clunk that would not show wear. Must be the bearings or something hidden from view.


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## Underdog (Oct 29, 2012)

I was never able to find a replacement aftermarket motor. It's just too specialized.
I've found several accounts of 1642 motors gone bad over on Sawmill Creek - and all of them were attributed to a "bendy" motor shaft allowing the armature to hit the windings. You won't find a huge mess, just a few contact spots where the armature hits.
I sold mine after won a drawing for a Stratos lathe (see my review) at the AAW Symposium in 2016. The guy that bought it ran it for a while, and* then the motor finally failed, taking out the Inverter at the same time*. At least that's what I'm told.
Best to just bite the bullet and get a new motor. Obviously the bearings aren't helping.


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## jimintroy (May 4, 2019)

Thanks, Jim.

-Jim


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## Nubsnstubs (Aug 30, 2013)

Have you tried checking the pulleys? ............... Jerry (in Tucson)


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## jimintroy (May 4, 2019)

Thanks, Jerry. Yes I did re-tighten down the setscrews a couple times and they had occsionally backed out an 1/8 turn or so but the tightening didn't correct the problem. Jim (in Georgia) has me worried now that my power issue might be my inverter, which, last I checked, was more expensive than the motor.

Anybody know how to check the inverters? Mine is turned against the wall so it's hard to read or interact with but I've wondered about the adjustment knob on it. I've read about some guys who have re-programmed theirs once they found out the password. I just want to make sure mine is working right.

-Jim.


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## jimintroy (May 4, 2019)

So here's the epilogue:

I put the motor back together and continued to use it-knocking and all-while I ordered another motor from M&M Tool Parts. That was about $525 delivered. I noted that the manufacture date was 2018 so it's possible that they've made improvements, but anyway it's not old stock.

My best guess is that the bend in the shaft was causing the pulley end of it to knock against the end cap. Another possibility is that the knocking was taking place within the bearing itself. The bent shaft might also have rapidly worn out the pulley end bearing as there was always radial play at the pulley end even with a weeks-old bearing.

Another significant observation was that the old motor vibrated excessively when it was unloaded and the RPMs were cranked up. You could feel it through the floor. The new motor runs as smooth as silk.

So I'm back in business again and I replaced the spindle bearings along the way so that end of the machine is pretty well restored. For a fleeting moment I lusted after one of the Laguna lathes but that (and the Robusts even more so) was just too far outside the budget. Plus, I couldn't imagine what I'd do with the 1642 if it wasn't woking. To scrap it would be a crime.

Thanks for all the input, folks.

-Jim


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## Underdog (Oct 29, 2012)

Well. Glad you're up and running again. It kinda stinks when your lathe is down. Hate that you had to spend the $500+, but that was the only way…


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