# Jet 10x24 headstock repair



## john mullen (May 5, 2014)

I hope this is the right place to ask for repair help for my JET 10X24P.
I was running the lathe in the lower gear range with the bull gear lock pin in the un locked position and after a while I think the pulley set has become frozen to the spindle. It just locked upanic: when I un do the back gear  the spindle turns as usual but without the bull gear being pined. the bull gear and pulley set will not rotate separately to realign the bull gear locking pin. what can I do to fix this problem. I want to take the spindle out and wonder if it will even come apart now. anybody ever have this problem before?? what do I do to get it apart?


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## Rapscallion (May 5, 2014)

When I started repairing the headstock of an old Colchester Triumph I looked for a manual for the machine first so that I could see how it all goes together. You might want to try the same.


John Mullen )


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## john mullen (May 5, 2014)

I do have the manual and it shows the exploded view and it is self explanatory  but no info on the removing the spindle with frozen v belt pulleys. I need help from someone who has experienced this problem and how they took the spindle out without totally destroying it


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## Rapscallion (May 5, 2014)

Oh, ok. I've never had that experience.All the best with it.


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## john mullen (May 6, 2014)

that's ok thanks anyway


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## john mullen (May 6, 2014)

Ok I got it apart today to find the brass bushings inside the pulleys of the headstock had not been properly lubed by the owner before me. there is a set screw in the grove of the center pulley that you remove and oil the bushings. I should have checked it before using the back gearing. live and learn.... the good news is that it hadn't done any damage to the spindle and I was able to repair everything good as new. I did damage one seal and that will delay putting it all back  together.  A trip to the bearing house tomorrow and ill zip it back up good as new:allgood:


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## john mullen (May 7, 2014)

I got the headstock back together today and it had a light noise in the bearing next to the chuck. I had no slack in the spindle but I tightened the bearing pre load some more and it went away. I wonder how much pre load there is supposed to be there on a used bearing setup. Any advice from someone with experience please advise... John


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## Kernbigo (May 8, 2014)

what kind of bearings are they angular contacts or taper roller?


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## john mullen (May 13, 2014)

Kernbigo said:


> what kind of bearings are they angular contacts or taper roller?



tapered roller


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## george wilson (May 13, 2014)

John,you do not live far from me. Is your Jet a belt drive or a gear head? I had a belt drive back about 1975. I wish I still had it. Very smooth finishes with it. Now,I have a Hardinge HLVH. It has a limited thread selection.32 threads IIRC. My large lathe is a 16" x 40" Grizzly made in Taiwan,1986,still like new. I have found extra gears to mount on the QC gearbox,to double or halve the indicated thread,so pretty good selection there.

Be sure to oil the shafts that the gear train behind the headstock runs on. Some of those shafts are cast iron,and will wring off if they seize up from lack of oil. I had that happen once back when I was new to machining. Luckily,the lathe still ran,without power feed,and I was able to turn a new shaft from steel and fix it.

Oil the bushings in the quick change gear box too. Oil the bushing at the tail end of the lathe's lead screw. Look every where for oiling points. I squirt a little oil in front of the tailstock's base sometimes before I'll slide it. I keep a film of oil on the ways.


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## Kernbigo (May 13, 2014)

Set the bearings up with a indicator and leave about .001 end play cold , taper rollers can't be run with zero end play they have to have some when they warm up. You may be able to get it down to .0005, bit try .001 first. I worked with the timken co. years ago on a besly double disc grinder, they thought they could run them with zero end play but after a short time they seized up.


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## john mullen (May 16, 2014)

Kernbigo said:


> Set the bearings up with a indicator and leave about .001 end play cold , taper rollers can't be run with zero end play they have to have some when they warm up. You may be able to get it down to .0005, bit try .001 first. I worked with the timken co. years ago on a besly double disc grinder, they thought they could run them with zero end play but after a short time they seized up.



I always thought that cone bearings were set up with a light pre load. I have set up many rear gear sets (ring and pinion type)with about 8 inch pounds of rotational drag as per Ford 9inch instructions . Just wonder why this would not apply on any cone bearing. I do not want to kill the bearings on my lathe as I have them set up this way now. I'll need more info before I run it... Thanks for the info..John


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## Kernbigo (May 16, 2014)

how do you set your trailer bearings,one lock back off about .004 clearance , no pre load due to heat and expansion, try .001 clearance, and if they run cool,then try .0005 clearance,at least you won't destroy them


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## john mullen (May 18, 2014)

Kernbigo said:


> how do you set your trailer bearings,one lock back off about .004 clearance , no pre load due to heat and expansion, try .001 clearance, and if they run cool,then try .0005 clearance,at least you won't destroy them



Thanks for that info. I did notice some heat on The chuck end of the head stock with my currant setting (not hot, just warm)  but not on the other end of the spindle shaft. I wonder why that would happen?  I'll redo the bearing set-up at .001 and give that a try


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## Kernbigo (May 18, 2014)

If you have oil cups add some mobil one that will help also


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## john mullen (May 19, 2014)

Kernbigo said:


> If you have oil cups add some mobil one that will help also


Thanks, it has oil reservoirs for each bearing with a site glass to see the level of oil .


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## john mullen (May 22, 2014)

Kernbigo said:


> Set the bearings up with a indicator and leave about .001 end play cold , taper rollers can't be run with zero end play they have to have some when they warm up. You may be able to get it down to .0005, bit try .001 first. I worked with the timken co. years ago on a besly double disc grinder, they thought they could run them with zero end play but after a short time they seized up.



I reset the spindle bearing end play at .001 and it was a little noisy  so I reset it at .0005 and it sounds good and runs cooler. I find that the chuck end of the spindle still runs warmer than the outer bearing . I assume it is heat coming from the work going into the chuck and then to the shaft and bearing .Its around 50% warmer on the chuck end. Is that normal??


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## george wilson (May 23, 2014)

It is normal for the front bearing to be warmer. It is carrying the weight of the chuck and the work,unless supported by the tailstock. Even if supported by the tailstock,the thrust of the tailstock adds to friction in the bearing.


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## john mullen (May 23, 2014)

george wilson said:


> It is normal for the front bearing to be warmer. It is carrying the weight of the chuck and the work,unless supported by the tailstock. Even if supported by the tailstock,the thrust of the tailstock adds to friction in the bearing.


Yeah George! That makes since. it's working very good now


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