# Atlas 10F Reverse Gearbox - Questions



## rfdes (Apr 26, 2014)

It is my understanding that the small reverse gearbox was one of the weak points of the 10F design and Atlas eventually abandoned the design.
Well, my gearbox is definitely 'finicky' and has been from day one.  There are times where sliding the lever struggles to mate with the appropriate
gear and I have to futz with the lever back and forth to get the parts to mate.  I've had mine apart for cleaning and inspecting but don't see anything
obvious.  I have heard stories of others who claim there gear boxes work smoothly.  Does anyone have any tips/pointers in getting the gears to better behave?  
I suppose buying new parts is an option but I would rather do things on my own (more fun that way).  Hopefully, there are some modifications available that
 might make these gear boxes work a bit more smooth.

thanks for any help you can offer...
Jim


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## pdentrem (Apr 26, 2014)

I feel your pain. I would simply hold the lever over with a little pressure until the shift collar would finally engage. Thus I never found a solution for mine. 

I did change the three gears at one point when one of them disintegrated. As for engagement issues with the sliding tooth gear (clutch), it is actually called a shift collar #9-50A. It is the nature of the beast. Putting a slight bevel on the sides of the teeth to ease the engagement with the side gears might help. Maybe?

I noticed that there has been a couple versions, the older was more of a single tooth dog clutch. As a real single dog clutch it would engage just about at anytime, almost 300 degrees of rotation, except for when the dogs were lined up. Perhaps it was abandoned due to the higher breakage of the smaller dog pin. The newer style that you have is stronger but only meshes in 6 possible positions, every 60 degrees.
Pierre


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## Wierd Harold (Apr 26, 2014)

This came up a while ago and according to wa5cab you should not shift under power but only when the lathe is stopped .
As to the old style single dog box, I have this on one of my lathes and it only engages in one spot in 360 with only a couple of degrees play.
HWF


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## pdentrem (Apr 26, 2014)

Just about all the time, if the lathe is not running, you will have to manually turn the spindle to engage the shift collar in either direction.

Harold
Do you have any pictures of the older style? I have only seen crappy ones that showed a half circle cutout.
Pierre


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## Wierd Harold (Apr 27, 2014)

These are the best pics I have on hand. If these won't do I can snap a couple tomorrow as this lathe is apart at the moment'

This is the "right hand gear" and you can see that it has a single 180 degree cutout.



and this is the "shift collar with the matching 180 degree single dog.
This not original as it was missing when I got the lathe. 
This was actually the first part I made on the lathe.



HWF


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## pdentrem (Apr 27, 2014)

That explains your comment on the very narrow engagement window. It is not like the usual dog clutch. Thanks for that.
Pierre


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## wa5cab (Apr 27, 2014)

Harold,

I must have been thinking about the tumbler style (with spur gears) when I made that comment, or didn't realize at the time that it was a dog clutch.  It wouldn't be very practical to adhere to that rule with the parts photographed below, and with the amount of metal involved I would agree not necessary so long as the shift is made "smartly".  The power cross feed is also not practically shiftable unless the lead screw is turning because the two gears engage from the side.  The shift should be made rapidly, though, to avoid damage when only the edges of the teeth are engaged.

Actually, the reversing gearbox wasn't abandoned on the 10" Change Gear models until production ceased in 1957.  But AFAIK it was never used on the 6" or 12".

Robert D.



Wierd Harold said:


> This came up a while ago and according to wa5cab you should not shift under power but only when the lathe is stopped .
> As to the old style single dog box, I have this on one of my lathes and it only engages in one spot in 360 with only a couple of degrees play.
> HWF


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## rfdes (Apr 27, 2014)

My gearbox seems to work smoothly at times then it wants to hang for whatever reason.  My inspection shows the parts don't *appear* to be in bad shape and was
wondering if there is some alignment trick that someone may know of.

Thanks again
Jim
WB5KYE


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## wa5cab (Apr 28, 2014)

Does it balk at engaging or disengaging?  Or both?  Do you have the single clutch dog shown below?

Robert D.


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## rfdes (Apr 28, 2014)

wa5cab said:


> Does it balk at engaging or disengaging?  Or both?  Do you have the single clutch dog shown below?
> 
> Robert D.



Hi Robert -
It only gives me problems when I attempt to engage.  My unit has the multiple dogs (something like 60 deg apart).  As I mentioned, there are times
it will engage smoothly 5 times in a row, say from the neutral position to the forward, then will be contrary for the next dozen attempts or so.  I need
to take it apart again for another inspection, I suppose.

Jim


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