Atlas Mill Followed Me Home

The 5 step pulley was what I meant. I don't know nothin about the bearings for the Jack shaft.


Steve Shannon
 
I've been looking at the parts lists; it's a little difficult to tell from the drawings but it looks like the MF model is supposed to have a four step pulley on the motor and the countershaft. The smallest step on the five step pulley on the countershaft isn't aligned with the motor pulley; the other four look like they line up. I'll just ignore that smallest step. If I were to use it the belt would be too long anyway.

I grabbed a copy of the drawings the other day for the arbor and arbor driver. They look pretty straightforward to make. I'll keep my eyes open for some spacers. I believe I probably have the 7/8 inch arbor now. I would like to assemble one of each, with spacers.
Thank YOU for the sketch that enabled that drawing. If it wasn't for the great people like you that inhabit this forum I would be having to reverse engineer it myself. It really does make a difference!

Steve Shannon, P.E.
 
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Just as an observation from a relative newbie, a person can do a lot with the Atlas Horizontal and end mills, shell mills, etc using various holders right out of the spindle.. I've seen some impressive work done this way. However, to take full advantage of this tough little machine, an arbor using the proper stack of spacers to place the cutter(s) in their optimal position over the table, and the over arm with its brace to support the outboard end of the arbor, are extremely useful if not downright required. I'm thinking the additional vertical support arm may be a bit of overkill, but it DOES add even more rigidity to the setup.

What brought this up was the OP's comment about the 7/8" arbor and wanting to get all three. I'm wondering whether there is an advantage of having a heavier arbor shaft beyond ability to fit different cutters one might find? Is additional strength a significant factor? Also on the matter of the number of pulley sheaves (and thus speeds) does there seem to be sufficient advantage at stake to merit "retrofitting" a MFC with older type pulleys to gain a wider range and number of speeds? Inquisitive minds want to know!

Froggie
 
It's been my experience that in this case, size does matter. Anytime you can use a tool or attachment to provide more rigidity it's a win - win to gain accuracy.
In regards to the pulley, it could be handy to have more speed variations. It depends on the work being required and the tool bit being used. And of course the speed vs. feed.
Having another speed choice could prove beneficial.
 
The reason I want the 1 1/4 arbor is because my neighbor thinks he has a a bunch of cutters for that size that he would give me. If I'm all set up to turn the MT2 it's not much of an effort to cut three blanks instead of two. Then, because the diameter of the drive hub on the arbor is 1 3/8", I already must have sufficient diameter stock for the 1 1/4 arbor. As other say, the part is already in there.
I agree that the vertical bar adds support, which the extra mass of the 1 1/4" arbor, hanging on a MT2, may require. The other beneficiaries are the nose of the spindle and the arbor support piece M1-60, which may experience torque as a result of the extra sag which may occur.
I've toyed with the idea of boring out the largest arbor. The material at the very center of any solid shaft adds mass without adding much strength. I wouldn't take much out, just enough to reduce the weight to that of the one inch arbor.
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Steve Shannon, P.E.

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Getting back to the pulleys, all of the Atlas mills (like all of their metal lathes) came with a 2-step motor pulley and a matching 2-step countershaft pulley. Because both pulleys are cantilevered on the end of the motor or counter shafts, I would avoid longer pulleys.

The deal with the cutout (see the final parts manual MMB-5) on the rear of the Housing is that only the M1-1A version had it. The M1-1 that came on the base and A-model mills was a one-piece housing. The M1-1A came on the B and C models of the mill.
 
Mine only has a single pulley for the motor and countershaft so I will have to see about getting/ making the proper pulleys in a while.
I like Steves idea of having all 3 arbors available for when tooling is available at a good price! What grade steel would I use for the arbors?
I think the larger shafts would allow a better, deeper cut etc as the extra mass will help keep the machine from stalling or chattering....yes bigger is better in most things but the smller shaft would also add more versitility and some extra clearance on some odd jobs?
Rodney
 
Going by the photo in the first post of this thread, it looks to me like a much of the countershaft assembly has been replaced by a previous owner. The step pulleys, shaft, bearings and the casting that holds them don't look original. The casting the bolts directly to the side of the mill does look original though.

Here's a photo of mine with the guard removed. (The holes at the end of the countershaft are for mounting the guard.)

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wa5cab said:
Getting back to the pulleys, all of the Atlas mills (like all of their metal lathes) came with a 2-step motor pulley and a matching 2-step countershaft pulley. Because both pulleys are cantilevered on the end of the motor or counter shafts, I would avoid longer pulleys.

The deal with the cutout (see the final parts manual MMB-5) on the rear of the Housing is that only the M1-1A version had it. The M1-1 that came on the base and A-model mills was a one-piece housing. The M1-1A came on the B and C models of the mill.
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Robert D.: I see what you mean. M6-427 and M6-428 were both two step pulleys. Where mine differs is in the pulleys for the countershaft to spindle. For my serial number both of those are four step, M1-79 and M6-80.
Thank you also for the tip about the back cover for the M1-1A. I won't even consider routing coolant lines through the rear of the housing.

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VSAncona said:
Going by the photo in the first post of this thread, it looks to me like a much of the countershaft assembly has been replaced by a previous owner. The step pulleys, shaft, bearings and the casting that holds them don't look original. The casting the bolts directly to the side of the mill does look original though.
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Vince:
I'll post some pictures of the countershaft assembly later today if I get a chance. After today I'll be traveling for a week and I seem to have found lots to do before leaving, so I might not get to it; please forgive me. What leads you to believe that the step pulleys, shaft, bearings, and casting have been replaced? Mine is model MF, serial number 725, which may be slightly different. What's yours? I would necessarily be surprised if some of mine has been replaced. There's a chip in the base casting, so at some time it struck something hard.
Does anybody have an extra knob: S7-145?

Also, I see a reference to a boring bar arbor, shown in figure 14 on page numbered 4 (fifth page in the MMB-5 PDF). Has anybody got one, or a factory drawing? If I'm going to be making replacement arbors I might as well make one of these also.
It's Monday and now that I'm retired it's a fun day!
Steve
 
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