# Atlas MFC Mill : Replacement reverse gear



## ThinWoodsman (Jun 7, 2020)

I decided to finally take a look at why the reverse feed (left-to-right, facing spindle) on my MFC mill never worked. Popped the hood and .... the gear is missing!

Specifically, part number MF-101-20A, the rightmost of the two gears at the top of the MF-58X reverse tumbler assembly. Does anybody know of a suitable replacement? If not, can an Atlas owner provide me with the measurements (diameter, number of teeth, tooth-depth/pitch.module if possible) needed to fabricate a replacement?

Thanks


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## CluelessNewB (Jun 7, 2020)

First check with Atlas/Clausing, they may actually still have the part (but it won't be cheap)   Typically they will provide an engineering drawing if they don't have the part. 

I believe you can email them using the address below:

info@clausingsc.com


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## wa5cab (Jun 7, 2020)

You will probably have better luck if you call them at 1-800-323-0972 and ask for old Atlas parts.  They are in EST,

The gear, from the part number, is a 20T but we have no further details on it.  You will also need the other parts shown on MMB-5 REV 8-1.  Specifically:

MF-64 Bushing (may come already installed in the gear)
MF-65 Bearing
M6-93 Washer
1/4"-20 X 7/8" Hex Cap Screw

Note that access to Downloads requires Donor status.

If they have the parts in stock, they will not give you any details from which you might make the parts.  If they do not have the parts, request a PDF or TIF of the drawings.  And forward a copy to me at wa5cab@cs.com and I will add them to the drawings in Downloads.

Also note that the tooth count of the two gears was chosen only to properly engage the MF-101-16L Tumbler Gear and has no effect on table traverse speed.


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## ThinWoodsman (Jun 7, 2020)

Yup, know already about Clausing and the other part numbers and the donor-status-required bit.
Thanks for the 20T.
I can probably infer the rest from the other gears.


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## wa5cab (Jun 7, 2020)

Yes, the only differences between the 20T that you need and the 24T that you have are the OD and the tooth count.


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## CluelessNewB (Jun 8, 2020)

Is there a 20T gear in the change-o-matic that would be the same diameter?


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## ThinWoodsman (Jun 8, 2020)

Not according to the parts list. I have the Change-o-Matic (love that name) removed and on a shelf at the moment so I can take a look next time I'm in the shop.


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## CluelessNewB (Jun 8, 2020)

I'm thinking M6-101-20 may be a 20T but with a bore keyed for the M6-70 bushing.


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## ThinWoodsman (Jun 8, 2020)

Ah, I see - I missed that one somehow, only saw the -40. Good idea, I'll check it out.


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## ThinWoodsman (Jun 9, 2020)

Sourced a replacement gear from a local guy with a bit of an Atlas graveyard. Will post dimensions for the curious when I pick it up.


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## wa5cab (Jun 9, 2020)

Sounds good!

For the record, first most of the Change Gears on the Atlas lathes, mills and shapers have part numbers beginning with one or two digits and/or letters (which ID the first machine that the part was used on) followed by "101" followed by the two-digit tooth count.  The four gears drawn to look like compound gears but having four different part numbers shown are each just 6" Change Gears.  Loading them onto an M6-70 double-keyed bushing turns them into compound gears.  So it is possible that M6-101-20 could have been bored out and turned into an MF-101-20A.  But not knowing the ID of the latter versus the ID of the key-ways in the former, I can't say whether or not the boring would have cleaned up the bore of the gear.  If it did, then it would have worked.

But fortunately, you didn't have to find out!


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