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Old 12-13-2009, 12:30 AM   #1
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Default Feed screw on harbor freight mini lathe

Help! I was turning a crankshaft for a steam engine on my harbor freight mini lathe using the auto feed. Suddenly, it stopped feeding. I took off the cover to find the plastic gear was all chewed up where the key holds it to the shaft. I tried to turn the shaft with the allen wrench, but it doesn't turn. Any advice on how to proceed?


Mike



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Old 12-13-2009, 12:50 AM   #2
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Default Re: Feed screw on harbor freight mini lathe

this may be a dumb question but what oil have you been using to oil the lead screw bearings? Sounds like the lead screw seized up.
Call me crazy but I generally feed by hand except when threading.

To answer your question try some light or penetrating oil in the ends of the lead screw then follow up with spindle or way oil. spindle oil is lighter.
Littlmachineshop.com should have any parst you need to replace the old ones.
IIRc there are places that sell metal replacement gears if you want to go that route but beware it is good to have a cheap easily replace "weak link" to prevent major damage in such a case.
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Old 12-13-2009, 12:51 AM   #3
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Default Re: Feed screw on harbor freight mini lathe

Mike,

Don't know much about your particular lathe but can you release the auto feed ? If not there could be a bind up in your half nuts inside the apron.

Hope this helps.

Best Regards
Bob

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Old 12-13-2009, 12:59 AM   #4
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Default Re: Feed screw on harbor freight mini lathe


Found the metal gears

http://littlemachineshop.com/product...ory=1687114045
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Old 12-13-2009, 12:48 PM   #5
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Default Re: Feed screw on harbor freight mini lathe

Mike, I have two of those lathes and one with metal and one with plastic gears and have never had a problem with them, did you run into to the chuck or what ever you were cutting with the tool bit, that could be the problem of the gears, remove the gears from the drive train. leaving the one on the lead screw and make sure that the half nut if disengaged, then see if you can turn the lead screw from the gear, if that works you can start putting it back together and solve as you go, if all else fails send some pictures, Lathe Nut

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Old 12-13-2009, 10:38 PM   #6
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Default Re: Feed screw on harbor freight mini lathe

Thanks for all the advice. I took the lead screw off, and sprayed the bearings with wd-40. I then wiped it dry, and put some high speed oil on the bearings. After working a while, I was able to make it turn properly. I guess I wasn't getting enough oil on the bearings.

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Old 12-13-2009, 10:47 PM   #7
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Default Re: Feed screw on harbor freight mini lathe

Slightly off topic, are ALL of the Harbor Freight lathe leadscrews metric thread?

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Old 12-13-2009, 11:19 PM   #8
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Default Re: Feed screw on harbor freight mini lathe

The lead screws on most of the 7x lathes is 16TPI

The lead screws in the cross slide and compound are usually metric unless you bought the Micro Mark machine or converted to the OE dial mounted DROs.

I used ot have a 7x10. I got better.

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Old 12-14-2009, 03:00 AM   #9
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Default Re: Feed screw on harbor freight mini lathe

Mike, glad that you are going again, Lathe Nut



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