# Atlas Gears



## dgehricke (Apr 2, 2015)

I have a 10F with the change gears,so my question is this what are the letters for on the gears i.e. 64A or 64B or 64 as well as some of the other size gears,they are all the same thickness and the hub is the same on all the gears, so maybe I've been living under a rock for the last 20 years  or I missed the boat.Can someone kindly fill me in and explain why.
Thanks
dgehricke


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## RJSakowski (Apr 2, 2015)

Numbers on a lathe gear usually denote the number of teeth.  Not sure about the A and B.

Bob


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## dgehricke (Apr 2, 2015)

come on Bob, I knew I should have added that I am aware that the numbers designate the number of teeth on the gear.I still want to know what the letters designate.
At least were getting warm.
Regards
dgehricke


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## RJSakowski (Apr 2, 2015)

dgehricke said:


> come on Bob, I knew I should have added that I am aware that the numbers designate the number of teeth on the gear.I still want to know what the letters designate.
> At least were getting warm.
> Regards
> dgehricke


Sorry dgehrckel,  I had no previous knowledge of your experience level.  I looked at a parts list for the 10F and the change gears all have a 9-101 prefix followed by the number of teeth and an "A". Is it possible that the B indicates a production change?  The parts list I was looking at was from 1966.

Bob


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## Rob (Apr 3, 2015)

I haven't heard of one with the B but the original gears for the 10/12 inch did not have a A following the tooth count and the hub was thinner.  The later ones with the A following the tooth count have a thicker hub.  I not sure but I seem to remember that the original ones have a 3/8 hub thickness and the A have a 1/2 hub thickness.


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## dgehricke (Apr 3, 2015)

RJSakowski said:


> Sorry dgehrckel,  I had no previous knowledge of your experience level.  I looked at a parts list for the 10F and the change gears all have a 9-101 prefix followed by the number of teeth and an "A". Is it possible that the B indicates a production change?  The parts list I was looking at was from 1966.
> 
> Bob


I have done a lot of looking to find info about the letters and what they designate over the years and no luck I also checked the measurements and all my gears are the same and the letters only appear on one side of the gear i.e. 64 or 32 on one side and the other its 64A or B or 32 A or B. only the smaller gears like the 24 or 20 have no letters
None of the gears have been cut down or machined in anyway,I also know there is a bulletin from Atlas about cutting the gears down.
My apologies for the first answer to your post I really should have posted that I was aware of the tooth count, MY Bad. Thanks for your response hopefully I'll get to the bottom of this.
Regards
dgehricke


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## JOEZ (Apr 3, 2015)

dgehrickie
   I have  several gears that have different (Hub) thickness on my change gears. I will try to make a list if your interested?
I have some with letters and others that don't.
          Joez


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## wa5cab (Apr 4, 2015)

The original change gears on the Atlas 9" have part numbers 9-101-nn (where "nn" is the tooth count).  These have a 3/8" face and a 3/8" hub, and the largest gear made is a 96T.  These were also used on the 10" up through 10D (and upgraded 10E) and on 12" up through 101.07361, 101.07381 and 101.7401.  The Atlas 10F and all remaining 12" use change gears with part numbers 9-101-nnA.  These have a 3/8" face and a 1/2" hub and the largest gear made is a 64T.  The A can be turned into a non-A by machining 1/16" off of both sides of the hub.  To use a non-A gear on a later lathe requires two 1/16" thick double-keyed spacers everywhere but on the screw gear, where they do not need to be keyed.


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## dgehricke (Apr 4, 2015)

JOEZ said:


> dgehrickie
> I have  several gears that have different (Hub) thickness on my change gears. I will try to make a list if your interested?
> I have some with letters and others that don't.
> Joez


Joez,
No need for a list but I do appreciate the offer I think the post from WA5cab below may have answered my question.
Thanks again
Regards
dgehricke


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