Atlas Mfc - Motor Pulley Size? Spindle Belt Size?

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