# Atlas Mfc  - Motor Pulley Size?  Spindle Belt Size?



## CluelessNewB

Does anyone know what the outside diameters of the two steps are on the motor pulley for an Atlas MFC mill.  I believe the part number is 10-428 or M6-428.

Also does anyone know what the MFC spindle belt size is?  

Thanks!


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## CluelessNewB

It appears that this pulley was also used on the 618 and maybe even the 10F lathe.  The 10-428 may be just the reducing bushing rather than the pulley part number.  I believe is M6-428 is the correct pulley part number.


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## JPMacG

Thanks for posting Rich.  I have the same question.


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## wa5cab

Rich,

Unfortunately, I do not have the commercial part number for the MFC spindle belt.  The motor belt is a 4L350 (Atlas part # L3-125, same as on the early 12" lathes).

The motor pulley on the MFB and MFC is a 10-428.  This has a 5/8" ID hub.  The 5/8"X1/2" reducing bushing is a commercial part and has no Atlas number.  The same pulley but with 1/2" ID is 9-428.  The OD's of the two pulley grooves are 4.390" and 1.930".  Center-to-center distance between the two grooves is 0.625".

The motor pulley on the MF and MFA is an M6-428, same as on all of the Atlas built 6" lathes except for the MK2.


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## CluelessNewB

Thanks!


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## JPMacG

I'll call Clausing/Atlas on Monday and ask if they still carry the 9-428 or 10-428.    I'll post what I learn here.


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## JPMacG

Actually I need that same pulley for my Craftsman 12x24 lathe.  When I bought it from my neighbor many years ago it came without a pulley and I installed just a single sheave pulley that I had in the junk box.


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## wa5cab

If anyone is serious about making a 10-428, I have a machining drawing that one of the Yahoo members worked up and made one from.  I haven't put it or any of the others back into Downloads because as Downloads currently exists, it would be pretty difficult to find anything, and uploads can currently only be done one file at a time.  Would take roughly forever.


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## CluelessNewB

I might be interested in making one.  I will try other options first.  If I do try to make one I would probably try casting a rough shape first rather than turning from stock.  I have a nice Baldor 3/4 hp 1725 3 phase motor looking for a job, it might be easier to pick an intermediate pulley ratio and use that with a VFD.


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## JPMacG

A pulley would be beyond my machining skills.  I think that getting the grooves to the proper widths, angles and diameters (simultaneously) would be too great a challenge for me.

I'm thinking of purchasing two single-sheave pulleys of the needed diameters, turning down the raised boss on one, and bolting them together at their hubs.   I could put a shaft through both of them and match drill the bolt hole pattern.   http://www.electricmotorwarehouse.com/pulley/cat25.pdf


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## wa5cab

Rich,

Unless you make it out of cast iron, a pulley made from a cast blank (aluminum) will not be nearly as strong as one made from wrought stock.

Jon,

Look more carefully at the section views of the cast iron pulleys from Leeson.  The face opposite the hub is not flat on any of the three types.  And on the larger PD ones, neither face is flat.  So that wouldn't work very well.


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## JPMacG

I called Clausing this morning.   They do stock the 9-428 pulley.   It is $96.68 plus shipping.   That's a bit too much for me.

Robert D., Thanks for the heads up on the Leeson pulleys.  I see the problem.


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## VSAncona

I asked Clausing about the spindle belt when I was restoring my MFC. They told me the belt is a Gates 3280.


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## wa5cab

Jon,

Did they quote a price on the 10-428 (very few 1/2" dia. shaft 1/2 HP or larger motors made today)?


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## JPMacG

She said that when she looked up the 9-428 she was referred to the 10-428.   She said a reducing bushing was included.   I did not ask the price of the 10-428.   Maybe it excludes the reducer and is less expensive.

I might be wise to get a pulley that uses a 5/8 inch shaft with a reducer.   If my 60 year old Atlas motor gives out I can use the pulley with a modern 5/8" shaft motor.


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## wa5cab

When she said that a reducing bushing was included, she was referring to the 10-428.  And if she looked up 9-428 and was referred to 10-428, then the price that she quoted you was for the 10-428 with bushing.


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## JPMacG

I went ahead and purchased two single groove Leeson pulleys.  The small one is an AK20 and the large one an AK46.   They are virtually identical in OD and PD to the original Atlas  -428 part.  For now, I plan to just swap out pulleys when I want to change speeds.   This takes only two or three minutes, so it is not a big deal.  I have to say that the Leeson cast iron pulleys are very nice looking - they appear to be more rugged and more precise than the original die cast Zamac (?) part.

.


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## lcato

If the motor shaft is long you can machine them to mount next to each other.


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## wa5cab

No, or I don't think so.  Early in the thread, Jon posted a link to Leeson pulleys (which included cross-section drawings), and at least one of the two didn't look suitable for stacking.


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## lcato

I was thinking like this.


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## wa5cab

The problem is that with at least the larger pulley, the rim hangs out farther than the hub on one side.  So that if the two pulleys were slid together until the hubs touched, the belt in the smaller groove would rub on the rim of the larger one.  I don't think that motor shafts are long enough to do what I think your drawing shows.


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## JPMacG

Unfortunately, the shaft of my Atlas motor is not long enough to do that.   But it is long enough (1-1/2") for me to position each pulley individually beneath the corresponding pulley grove on the counter shaft.  

I can see that swapping pulleys like I am doing would not work on a motor with a shorter shaft.   One would not be able to position the motor pulley directly beneath the outer pulley on the counter shaft.  I guess you could always move the motor on its mount, but that would be a chore.

I'm still thinking that I could modify the pulleys and bolt them together at their hubs, maybe with a spacer in between.   But for now, swapping pulleys will do.


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## wa5cab

If you do decide to cut the hub off on one pulley and bolt the two together with a custom machined spacer between them, be sure that all the screw holes are equally spaced and on the same hole circle diameter.  And that all of the bolts, nuts and washers are the same weight (generally the same length and diameter).  An out of balance motor pulley will cause vibration and accelerated bearing wear.


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## BillyT

wa5cab said:


> If anyone is serious about making a 10-428, I have a machining drawing that one of the Yahoo members worked up and made one from.  I haven't put it or any of the others back into Downloads because as Downloads currently exists, it would be pretty difficult to find anything, and uploads can currently only be done one file at a time.  Would take roughly forever.



i would like a copy please


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## wa5cab

Billy,

We got DOWNLOADS somewhat tamed.  I created a lot of sub-categories (folders), especially for those badges where we had a large number of files, including Atlas.  You will find the drawing under Atlas/Craftsman/AA.  Drill down to the Atlas & Craftsman Drawings category and there will be fewer files to look through.  The path would be 


List Of Categories (Click Here First For Alpha Sorted List) 1,826
Machine Manuals, Catalogs & Drawings 1,173
Atlas/Craftsman/AA 147
A/C Lathes 67
Atlas Drawings 38
Atlas Lathe 12


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## HalcyonDaze

If anybody's still looking for the belt(s), I got mine at Grainger.  These fit the stock pulleys, so if your pulley diameter is different, you'll need to allow for it.

Spindle belt:  Dayton 5L270G
Motor belt:  Dayton4L330H


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## wa5cab

Which model is your mill?  Base, A, B or C?  Because the pulleys are different for the different models, the belts may be different.


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## HalcyonDaze

Mine is an MFC.  The motor pulley is part# 10-428 and the counter shaft pulley is part# L2-679B.  The centerline of the two shafts is currently 9.5 inches c/c, adjustable.

My manual covers just about every model of the machine, and nearly all the parts are the same between the models.  They appear to have the same motor pulley on all the models, different counter shaft pulleys on differing models, the L2-679B is on models MFC, MIC, and MHC. 

I hope this helps.


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## wa5cab

HA,

OK.  Thanks.  But I run DOWNLOADS, and most (but not all) of the Atlas/Craftsman manuals and drawings in there came directly or indirectly from me.  So I have MP-2, MP-2A, MMB-1A, MMB-3, MMB-4 and MMB-5.  I'm still looking for MP-1, MMB-1, and MMB-2.

The motor pulley on the M1, MF, MH, M1A, MFA and MHA is M6-428 for 1/2" motor shafts (or M6-429 for 5/8" motor shafts, but that isn't shown on the original parts drawings or lists - I got it from Clausing when I bought one recently).  The 2-step countershaft pulley is M6-427 on the base models and M1-427 on the "A" models.  

But the reason that I asked what model mill you have is that someone else with an MFC had reported that his belts were 4L350 motor and 5L280 spindle.  Did you by any chance get your numbers off of original belts or did you put everything together and measure required length?  Unfortunately, in the case of the other reported belt numbers, I don't know the answer to that question.  But also, the Atlas part number shown for the motor belt on the M*B and M*C is L3-125 which is also the motor belt on all 14 models of the Craftsman 3/8" bed 12" lathes.  And dozens of people have reported it as 4L350.

I recently spent about an hour on the phone with someone in Tech Support at Clausing over the belt issue.  And about all that I learned is that they've lost all records of what the industry part numbers for all of the belts in all of the mills were.

Incidentally, although the fonts used in a lot of Atlas documentation (and most places that it appears on the Internet) makes it look otherwise, the second character in the model ID of the manual cross-feed models is actually a numeral "one", not an uppercase letter "eye".  So the first mill was the M1, not the MI.  And most of the original part numbers begin with "M1-".


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## HalcyonDaze

Mine had the original spindle belt when I got it, so it was just a matter of matching it.  The motor belt was figured using a belt length formula, but it took a  couple of trips to Grainger to get it just right.  I took the numbers I gave you directly off the belts.  I also took the part numbers for the pulleys directly off of the pulleys, and they match what's in my manual.

I read somewhere that the motor pulley on an Atlas lathe has the same step sizes, but the bore is 5/8" because it was equipped with a 1/2HP motor with a bigger shaft, whereas the mill was equipped with a smaller 1/3HP motor with a 1/2" shaft.

This brings us to the end of my knowledge concerning belts and pulleys on an Atlas mill.


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## wa5cab

OK.  But actually, the 6" originally had 1/4 HP and the 9", 10"  and early 12" had 1/3 HP as the recommended motor size.  At the time, most 1/3 HP motors were 48 Frame, not 56 Frame, so 1/2" shafts.  And for that matter, so were some 1/2 HP.  At some point maybe mid-War, the recommended motor sizes were changed to 1/3 and 1/2 HP.  And the 56 Frame became more common.  

The original 9" had a 1/2" bore single step motor pulley, 9-85.  When Atlas brought out the 9" Utility, which had or could be ordered with a conventional countershaft assembly, the motor pulley became the 1/2" bore 2-step 9-428.  When the 6" came out, it had a smaller 2-step 1/2" bore M6-428.  Which was later used on the M1 and M1A, etc.  56 frame size became more common so they added an M6-429 and a 10-428.  Which is what's on my 3996 made in 1980.  And is what was used on the M*B and M*C.  AFAIK, today all that Atlas makes are M6-429 and 10-428.  If you have a 1/2" shaft motor, you use a reducing bushing.


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## merix5

JPMacG said:


> I called Clausing this morning.   They do stock the 9-428 pulley.   It is $96.68 plus shipping.   That's a bit too much for me.
> 
> Robert D., Thanks for the heads up on the Leeson pulleys.  I see the problem.


Could I get the contact info for Clausing from you? I haven't found it in my searches. Thanks, Dennis.


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## wa5cab

Dennis,

Clausing telephone # is 800-323-0972.  Ask for old Atlas parts.  

FWIW, I bought an M6-429 (same as M6-428 except made for 5/8" dia. motor shaft) from them a few weeks ago.  It was a little more than what JPMACG quoted for the M6-428.  But it appears to have been machined from solid round 316 SS.  Heavy sucker.


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## merix5

Thanks a lot. I am an old timer, a toolmaker and machinist with 38 years. I'm going to split the pulley into two pieces and make it, rejoining probably with pins, but not sure yet. I'll redesign it so it is within the capability of the 12" Clausing/Atlas/Craftsman.
Then I'll post the drawing . Thanks again, Dennis M.


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## wa5cab

OK.  However, I can save you some time.  The 2-step motor pully for 5/8" shaft motors used since around the time of the introduction of the Atlas 10D and first Craftsman 12" through to end of production in 1981 is part number 10-428.  There is a reverse-engineered drawing in DOWNLOADS In the Atlas Lathe Drawings category that was drawn by a member of the A_C Group on Yahoo.  At least one pulley has been made from it that I know of.  The original factory drawing isn't available as Clausing still sells the pulley.  It is a little larger than M6-428 or 429.  The 1/2" shaft part number was 9-428.  It is identical to 10-428 except for the ID.


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## Mathurin

That is my first question, I have a Craftsman metal lathe 101.21400 the motor pulley is M6-429 with bore 5/8'' ! download the drawing for M6-428 is it the same dimension for the M6-429 except the bore 1/2'' ?

Thanks


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## Silverbullet

Good deal going with cast iron over aluminum pulleys . I know cost is everything in a build , but why did the company cheap out with the pulleys. I own one and have a couple things to fix and replace. The belt guard I'm gonna draw on aluminum plate and cut the metal to shape of the original . Table handle is getting a round lathe handle picked up on eBay. Other then that it's cleaning and lubeing. I'm going to make a couple arbors , one it came with and two others in 7/8" and 1 1/4" .  Pick up some 2 morse collets and maybe make the arbor cover not needed but they had them . Anybody know what they're made of ?  I'm thinking of using wood , all it does is sit on the support bar and a dowel pin mounts it.


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## wa5cab

I think that the original M6-429 pulleys were Zamak.  But I bought one from Clausing recently (for the mill, actually) and it is machined from stainless.

The arbor covers on the mill were made of cast iron.  They were dropped from the "C" models because of the addition of the arbor support bar.


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## miken

wa5cab said:


> Which model is your mill?  Base, A, B or C?  Because the pulleys are different for the different models, the belts may be different.


Hi, I recently purchased an Atlas horizontal mill and I am trying to get it functional again. Unfortunately, the model number plate is missing. It does not have provisions (locking nut) for the large overarm support beam cover. The boss on the casting is there but not drilled, so I am thinking it is a later model, MFC? Any advice to help determine the model would be appreciated. My question is actually regarding the pulley on the motor shaft and the pulley on the end of the counter shaft. I am missing them and trying to confirm if they are in fact the same for all models? Are they; motor pulley is part# 10-428 and the counter shaft pulley is part# L2-679B? I have the two-step countershaft spindle drive pulley and think that is correct as M1-80B? I am unable to find drawings, or unable to download them. Any help is greatly appreciated as I am trying to nail down the diameters of each.
Thanks, Mike -


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## wa5cab

Most likely the mill that you have is an MFC.  MF is 4-speed x 2.  MFA is 3-speed x 2.  MFB and MFC are 2-speed x 2.  MF through MFB have a guard over the over-arm.  MFC does not but has instead an additional support added and a different rear cover.  You probably have an MFC.

This is all spelled out by parts manuals in Downloads but access to Downloads requires Donor status (any level).

If you do decide to become a Donor, be sure that you read the details on what each level adds.  Click on Donations in main tool bar.  System does not have provision for increasing or decreasing levels other than annually.


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## miken

wa5cab said:


> Most likely the mill that you have is an MFC.


Yes, that is what I was thinking. I found the manuals over on vintage machinery, but I don't believe either of the ones I found list the actual pulley diameters. In post #4 you list the motor pulley diameters as: "The OD's of the two pulley grooves are 4.390" and 1.930". Any chance you also know the countershaft pulley diameters as well? I believe they are much larger from appearance. 

Thanks.


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