# Atlas Craftsman 618



## forwheeler (Nov 28, 2012)

I am new to this group, machining and the lathe.
I don't understand the backgear setup. If I put the backgear in action then I can't rotate the assembly at all. Can someone shed some light on this?


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## FastPauly (Nov 28, 2012)

As far as not being able to hand rotate the chuck while the back gears are engaged is akin to parking your standard shift car on a steep hill in 1st gear....it is less likely to roll away vs leaving it in a higher gear.


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## forwheeler (Nov 28, 2012)

I tried it with the motor and the belt just slips. Maybe there is something seized plus I don't know if the countershaft gears are supposed to rotate separately or the spindle gears rotate separately when this is engaged.


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## kd4gij (Nov 28, 2012)

The bull gear. The one closest to the chuck has a pin that loks it to the pullys. you need to pull that out to disingaga the pullys when you yse back gear. Hope that make secnce. oh and disingage the pin before you put it in back gear so you can rotate the spindle to get to the pin. If you do not have a parts diagram of your lathe go to this yahoo group and sign up thay have all of the doc.for your lathe in the files section.

http://groups.yahoo.com/group/atlas_craftsman/


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## forwheeler (Nov 28, 2012)

Ok I see the pin now. It is kept in place by a set screw. Is the purpose of the backgear to slow the spindle way down?


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## kd4gij (Nov 28, 2012)

forwheeler said:


> Ok I see the pin now. It is kept in place by a set screw. Is the purpose of the backgear to slow the spindle way down?



 Yes that is the purpus. Threading and knurling are  done in back gear.


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## forwheeler (Nov 28, 2012)

Thanks for your help.
I have a boring question. Should I start a new thread here?


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## AR1911 (Nov 28, 2012)

Set screw?  there are no set screws in the bull gear or the stepped pulley, or the backgear. What looks like a setscew is a plug in the oil port. It should be screwed in flush, but no more, and not tightened.

Are you sure you have the right pin?
It's on the right side of the biggest gear, closest to the chuck. You pull the pin out and turn it 90 degrees to let the big gear freewheel on it's own hub.
I am assuming your have the early version of the 618. The later Mk2s were entirely different.

You do need to be careful with that. the gear teeth at the back are cast pot-metal and easily broken. trying to turn it while it's locked up, for example to loosen a stuck chuck, is what breaks those teeth.


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## forwheeler (Nov 28, 2012)

Here are some pictures so you can see what I see.


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## forwheeler (Nov 28, 2012)

sssfox said:


> It's the pin in the bottom picture.  If it hasn't moved for a while, you may need to use a little force.


Yes and it looks like it might be held in place by a set screw in the other picture.


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