# South Bend 9a reverse problems



## brandon428 (Feb 17, 2021)

Hi all,

Was running my lathe today with the back gear engaged, and flipped the motor in reverse to get a reverse feed.  After using it for a few minutes, the chuck and spindle froze where the belts were turning but the spindle was not.  I turned off the machine and could turn the spindle by hand (though it was tight) and the carriage was really tight/hard to move longitudinally.  I took it out of the back gear, and it worked fine again.  Re-engaged the back gear, same problem.  Flipped the motor back to forward, and everything worked fine again.  Ran it for 20 minutes, went back to reverse, and same "stuck" problem after a minute of usage.

Has anyone run into this before?


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## mmcmdl (Feb 17, 2021)

Did you ever get a rocker ? I'll give you mine for nothing if you take care of shipping .


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## brandon428 (Feb 17, 2021)

Nope.  I thought you were sending me one already!  I'll PM you.


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## markba633csi (Feb 17, 2021)

Disengage the leadscrew and gears completely to help isolate the problem.  Sounds like the backgear or spindle pulley is binding up somehow.  
Was anything in the headstock getting warm? 
-Mark


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## brandon428 (Feb 18, 2021)

Hmmm, how do I disconnect the leadscrew.  Is there a pin somewhere?


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## gradient (Feb 18, 2021)

I believe you can just disengage the gearbox speed/thead selectors from the pin holes and let them hang down or move the forward / reverse selector to the neutral position. Works on my SB.


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## brandon428 (Feb 27, 2021)

Looks like it's something in the quick change gearbox.  When I disconnect it the problem goes away.  Not packed with shavings, but hoping the gears aren't worn in one direction (reverse) only.


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## brandon428 (Mar 3, 2021)

And it looks like my gears are worn, and I can see why it would only happen in one direction.

Anyone know where I can buy new gears?  According to the parts diagram I need PT626NK1 (Pinion Gear 42,44) and A5619NK1 (Comp pinion 9,10).


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## martik777 (Mar 3, 2021)

You said: " motor in reverse to get a reverse feed"

You change the position of the reverse tumbler to reverse feed direction NOT the motor direction

Do you have a photo of those gears?


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## brandon428 (Mar 3, 2021)

Sorry, I have a motor switch that allows the motor to go in reverse, which I sometimes use in a pinch.  Same results if I use the reverse tumbler.

I can take a picture tomorrow, but here's the part sheet -- the ones circled are red are the thrashed ones.


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## martik777 (Mar 4, 2021)

Doubt you'll find those gears - You will have to make them or 3D print them. Can you choose another setting to avoid those gears?


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