# How to remove atlas 12" lead screw



## bkcorwin (Nov 11, 2013)

Hi All, I am trying to fix a problem with my gear train described in another post.  To do this I need to remove the lead screw but cannot get the screw to come out of the gear box.

I don't have any pictures, but I found one over on a different site that explains what I am looking for.  The thread was ended because you aren't allowed to discuss atlas brand machines over there (for reference as to what site im talking about).



That said, my question is shown in the picture.  How do I remove the lead screw from this end.  The tail stock end is free but I can't figure this side out.

Thanks much
Brian


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## Rob (Nov 11, 2013)

It should just pull out.  The only thing holding it in is the tailstock end bearing.


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## Privateer (Nov 11, 2013)

I am probably mistaken, but shouldn't it just pull out in the direction of the tailstock? Assuming there aren't any set screws in the little holes I saw in the picture.

Terry


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## dgehricke (Nov 11, 2013)

Brian,
 I have a 10 F atlas but I do not have a quick change gear box BUT I have disassembled a few when I was thinking of adding one to my 10F
the gears on the end of the gear train at the banjo should be removed, two bolts at the top of the gear box at the ways should be removed I think they are 
1/2 bolt head or 7/16 not sure. The end bearing this is a sacrificial bearing at the end of the lead screw at the tailstock.The next item is tricky the half nuts need to be opened as much as possible, at the saddle there are 2 bolts that hold the apron and half nut assembly together this should also be removed carefully. Once all this is freed up and disconnected the lead screw inside the quick change gear box has a couple of set screws that will need to be loosed and there is also a collar on the end of the lead screw left side as your facing it, I believe then you can slide out the lead screw.
any thing else give me a holler good luck


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## dgehricke (Nov 11, 2013)

Brian,
 Here are 2 PDFs that will help you with disassembly, the part that you are referencing is the clutch adjustment.I hope this helps.


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## bkcorwin (Nov 11, 2013)

Thanks that helps a lot.  The screw has been removed.  However I still can't remove the gear box.  I removed the two screws labeled A in that diagram, and the square bolt it talks about but the thing won't budge a bit.

Any ideas on the gearbox?


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## bkcorwin (Nov 12, 2013)

Well I got the gear box off.  Hopefully posting this information here will help someone else.  There were 3 socket head cap screws holding the gear box on to the machine.  One was visible on the front of the box, the second was visible by removing the label plate on the gear box.  The third is not located as indicated in the installation instructions.  The lathe is a quite new model, perhaps that has something to do with it?

In any case, the third screw holding the gear box on was visible by opening the top spindle cover.  Looking down through the opening there was the head of a socket head cap screw visible on the operator side way, that screwed into the gear box attaching it to the way.

The lead screw was simply stuck in the clutch mechanism.  To remove it I undid the two grub screws that hold the clutch assembly to the output of the gear box.  This allowed me to then tap the clutch off with a brass hammer.


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## wa5cab (Nov 12, 2013)

Brian,

My machine, as I said over on Yahoo, is about two years newer than yours.  And I have never had any need to remove the QCGB.  It does have the third socket head cap screw visible and accessible by raising the top cover.  What is the length?  I'll add it to the late model drawings and parts lists.  And when our Downloads comes back up, upload revisions.

I just went through about a dozen different parts manuals of varying vintages and none show that 4th bolt (3rd socket head).  Even the manual on the very late 3965 Metric model.  This last manual does show the 4th screw (the one with the jam nuts that goes through the bracket and foot) as a hex head and inserted from left to right instead of from right to left as do all other manuals.  Which way was yours and was the bolt square or hex head?

Also, as you have yours apart, you can answer another question.  All of the manuals (even the 3965 one) show four flat washers on the fourth bolt (through the foot).  But all show two of them as 3/8" and two as 5/16".  Can you confirm that they are all the same (3/8")?  Or are they all 3/8" but two are USS and two are SAE?  I don't see how any could possibly be 5/16".

Robert D.


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## bkcorwin (Nov 12, 2013)

Yeah I can check all that tomorrow.  I'll post back up here.

I'm taking it off just so I can have a look.  I had a terrible screeching grinding noise come up periodically that I cannot identify (though i do know its lead screw related).


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