Atlas Mfc - Motor Pulley Size? Spindle Belt Size?

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.
 
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.
IMG_0203.JPG
 
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.
 
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.
Click to expand...

i would like a copy please
 
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

  1. List Of Categories (Click Here First For Alpha Sorted List) 1,826
    1. Machine Manuals, Catalogs & Drawings 1,173
      1. Atlas/Craftsman/AA 147
        1. A/C Lathes 67
        2. Atlas Drawings 38
          1. Atlas Lathe 12
 
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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
 
Which model is your mill? Base, A, B or C? Because the pulleys are different for the different models, the belts may be different.
 
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.
 
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-".
 
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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