# Jet Mini Lathe Problems



## jedgerton (Sep 8, 2010)

OK, I need some help.  I have a Jet Mini Lathe that appeared to have some bearing problems.  When turning at ~4000 rpm for about 15 minutes, the headstock would get quite warm, in fact uncomfortable to touch.

I replaced the bearings hoping that would resolve the issue but upon removing the existing bearings, they appeared to be fine (smooth operation).  I replaced them anyway but the headstock appears to heat up at about the same rate.

In addition to the lack of improvement, the lathe is noticeably louder now and the noise sounds like it is coming from the thrust washer (I think that's the name).  The noise can be reduced by tightening down the hand wheel but I'm now wondering if that's where the friction/heat may be coming from.

Any ideas or thoughts?  Should I consider replacing the thrust washer?

I have another Jet Mini Lathe that shows no appreciable sign of heating up during use.

Thanks in advance for the help!

John


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## ROOKIETURNER (Sep 8, 2010)

My live center heats up, but never had my headstock heat up. Hope you get it resolved.


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## Dave_M (Sep 28, 2010)

Hi John,
Sorry I just noticed your question.  It sounds like you're having the same problem I had a while back.  The set screws on the hand wheel came lose on my Jet 1014 lathe and the hand wheel tightened up against the headstock too tight causing a lot of friction with the head stock.  I fixed it by by loosening the set screws on the hand wheel and then tightening the hand wheel tight against the head stock then backed off just under a 1/4 turn.  I tightened the hand wheel set screws and no more heat.  Runs good now.  

Hope that helps.
Dave


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## randyrls (Sep 28, 2010)

To join the Thread;  As Dave said, the Hand Wheel on the Jet mini applies "preload" to the headstock bearings.  The hand wheel should NOT be tightened completely on the shaft.  Tighten it, then back off a quarter turn then lock down the set screws.  The correct setting of the pre-load is just comfortably warm after 30 minutes of running at high speed.  If the headstock gets too hot to rest your hand on, back the preload off another one eighth of a turn.


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## jedgerton (Sep 29, 2010)

Thanks for all of the inputs but this problem is still unresolved. I removed the hand wheel altogether, put a mandrel in the headstock and applied force with a live center in the tail stock. It still heats up at about the same rate. My thinking is this eliminates fiction from the hand wheel but I'm not sure if absence of the handwheel might cause other problems. 

Any thoughts before I put this thing on the curb . 

John


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## ToddMR (Sep 29, 2010)

Have you called the company?


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## glycerine (Sep 29, 2010)

jedgerton said:


> Thanks for all of the inputs but this problem is still unresolved. I removed the hand wheel altogether, put a mandrel in the headstock and applied force with a live center in the tail stock. It still heats up at about the same rate. My thinking is this eliminates fiction from the hand wheel but I'm not sure if absence of the handwheel might cause other problems.
> 
> Any thoughts before I put this thing on the curb .
> 
> John


 
You said you put a mandrel in there and applied force with the tailstock.  Does the headstock heat up when just running but not under load?


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## jedgerton (Sep 29, 2010)

glycerine said:


> jedgerton said:
> 
> 
> > Thanks for all of the inputs but this problem is still unresolved. I removed the hand wheel altogether, put a mandrel in the headstock and applied force with a live center in the tail stock. It still heats up at about the same rate. My thinking is this eliminates fiction from the hand wheel but I'm not sure if absence of the handwheel might cause other problems.
> ...



I'll give that a try, good suggestion.  About calling the company, I haven't yet but I will do that before the trip to the curb.  By the way, if you ever saw my shop you would know that throwing things away isn't something I frequently do.

John


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## Skye (Sep 30, 2010)

Where is the headstock the hottest? Is it heating up down close to the motor?


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## Dudley Young (Oct 2, 2010)

You can't run it without the hand wheel on it. The hand wheel has to tighten against the rear bearing with the thrust washer in between. That is what makes the bearing turn. Other wise the spindle just spins in the inner race and will definitely cause heat and if dry will squeal like crazy. Do what lanman said. Make sure the thrust washer hasn't lost it's spring.


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## dalemcginnis (Oct 3, 2010)

Also check to see if the upper pulley on is loose.  Mine comes loose periodically and slips out of position to where it's rubbing against the frame.


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