# Atlas Frankenstein Lathe



## Jlwright3 (Dec 11, 2020)

So I have an atlas lathe that I am looking to get some more information about.

From my own research, it appears that a previous owner has taken a 10" headstock and mounted it to a bed from an Atlas 12" along with the 12" carriage and tailstock. It looks like they machined and adapter/raiser plate in order to bring the centerline of the spindle bearing inline with the center of the tailstock.

The serial number found on the bed of the lathe shows model number 3986, serial number 104562.

Any insight into the date and size of the headstock would be appreciated.

As of right now, the lathe appears to function without issue. My guess is it took a combination of 10" and 12" parts to get the gear train functional. I have limited pictures at the moment, but I can take more if necessary.


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## mickri (Dec 11, 2020)

It is my understanding that the 10" and 12" atlas/craftsman lathes used the same bed.  Robert (our atlas/craftsman expert) should chime in here for anything that you should be on the look out for.  If the tailstock alignment checks out you should be good to go.


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## Jlwright3 (Dec 11, 2020)

I have yet to check it out, I'm still in the process of thoroughly cleaning it and greasing/ oiling everything up. If there was a raiser made to adapt the 10" headstock to a 12" tailstock, I'm baffled at how they would have gotten the forward and reverse lead screws gears to line up with the quick change box. From some short tests, everything there works very well. 

Im thinking they might have just used the gear assembly from a 12" lathe? No clue. 

Very hopeful that everything lines up well.


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## aaronrumple (Dec 11, 2020)

Bed says late model 12". The feet are wrong for a 12".
The threading lever isn't a typical 12" Tailstock is a 12"
It looks like there is a riser block under the headstock.
Most of it looks like a 12"
I agree - it has been pieced together. But looks well done.


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## aaronrumple (Dec 11, 2020)

Was this added on to make the fwd/rev work?


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## Jlwright3 (Dec 11, 2020)

It looks like it was added to it and it works good. The side cover was also homemade. I was cleaning it up and some paint was chipped on the inside and you can see it was brazed together.

As soon as I feel comfortable with running it (cleaned and lubricate properly) I'll adjust everything and see how she cuts. Hopefully the person that pieced it altogether knew what they were doing.


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## wa5cab (Dec 11, 2020)

The 10" Atlas and the early 12" Craftsman did in fact use the same beds.  The late 12" Atlas and Craftsman are the same machines except for badges that say either Atlas or Craftsman.  The early 10" and 12" machines had 3/8" ways and the late 12" had 1/2" ways.  There was no late 10".  According to the nameplate, the bed is from an Atlas 3986, which is a bench model, not cabinet.  So step 1 is to  mic the ways to confirm but the way thickness should be 1/2" nominal.  FWIW, from 10F and 101.07402 on, all machines used the same "A" suffix change gears.  And both legs are consistant with 3986.


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## Jlwright3 (Dec 11, 2020)

The ways are 1/2"


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## wa5cab (Dec 12, 2020)

OK.  Then the lathe was originally a 3986 12x36 bench model.  It is sitting on a cabinet that has had the external cover on the left end removed.  It is hard to say from the photos  but I think that the counter shaft came from the 10".  I think that the one from the 3986 would have fouled the 10" back gears which are mounted to the rear of the spindle instead of underneath it as on the 3986.  The QCGB is probably from the 3986.

What is the purpose of the black ball between the speed chart and the drum switch?

The carriage, cross slide, compound and tailstock are all presumably from the 3986.  Which was probably originally made in 1976.


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## kcoffield (Dec 12, 2020)

I converted an older 12" Craftsman from rear to underneath countershaft installed on a 3996 (3986 is a bench model) style cabinet. It took considerable effort so it's sort of strange to see a 3986 style lathe converted the other way. Unless the original headstock was lost, I would have thought it far easier to just fix whatever the problem was with the original headstock rather than the effort to swap the 10" HS onto the lathe. With the degree of parts interchange, the 10" could likely have been the repair donor. Is the drive hardware inside the cabinet still present. Any chance the take off parts are available?

Best,
Kelly


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## Jlwright3 (Dec 12, 2020)

I didn't purchase the lathe from the person who combined the lathes so I'm not sure where any of the drive components that would have been in the cabinet may have ended up, but it has been converted into a storage area. 

The black nob is to lock the side cover in place. Those components we're home made, but whomever built them did a very nice job. 

Is there anywhere on the headstock casting I could look to determine it's year of manufacture? Also does it use the timkin tapered roller bearings? I assume it does.


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## wa5cab (Dec 12, 2020)

First, the lathe that supplied the bed, carriage, etc. was a 3986, which is a bench model with a countershaft assembly quite different from the one on the 10".  The cabinet, on the other hand, came from yet a third group of models that ended with the 3996.

There was considerably more to this "conversion"  than would be obvious to someone familiar with the later two 12" version groups and the 10" and early Craftsman 12".  As I wrote earlier, the last two 12" version groups had the back gears mounted under the spindle.  Whereas the 10" and all of the early 12" had them mounted behind the spindle.  That means that he couldn't use the 3986 countershaft assemble, which is smaller.  Assuming that the person doing the conversion was able to source the 2-groove spindle pulley used instead of the 4-groove cone spindle pulley used on all earlier Atlas lathes except for the 6" and 9", the conversion would have been far simpler.  The 2-groove spindle pulley will fit all of the 10" and early 12" spindles.  But in any case, he didn't do it that way.


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## aaronrumple (Dec 12, 2020)

What did that conversion entail?
I'm thinking of converting mine to underneath with either VFD or treadmill motor.



kcoffield said:


> I converted an older 12" Craftsman from rear to underneath countershaft installed on a 3996 style cabinet. It took considerable effort so it's sort of strange to see a 3986 style lathe converted the other way. Unless the original headstock was lost, I would have thought it far easier to just fix whatever the problem was with the original headstock rather than the effort to swap the 10" HS onto the lathe. With the degree of parts interchange, the 10" could likely have been the repair donor. Is the drive hardware inside the cabinet still present. Any chance the take off parts are available?
> 
> Best,
> Kelly


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## wa5cab (Dec 12, 2020)

Jlwright3,

We were apparently writing at the same time.

No, as far as I know, the only castings that Atlas/Clausing made that have a casting date cast in are the headstocks for the MK2 6".  My estimate of the manufacturing date is probably the best that you are going to get.  And as to when the 10F headstock was actually made, the best that I can say right now is sometime between 1939 and 1957.  I have asked several people at Clausing about paper documents and all have told me that except for the drawings, they were all either lost by accident or destroyed by the Clausing hands.

All of the lathes that Atlas and then Clausing made after 1945 except for the 6" used the same part number Timken bearings.

As to when the 10" headstock was made, if you have any other reason to pull the spindle, odds are about 3:1 that the spindle bearings will have dates engraved into them.  That practice stopped around late 1952.  So if there are no dates, late 1952 to mid 1957.  If there are dates, then the latest of the dates -0+1.  If you pull the drum switch and find that the original 10" motor switch was mounted in a round hole, then 1939 to 1942.  If the hole was originally square or rectangular, the late 1942 through the Summer of 1957.


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## kcoffield (Dec 12, 2020)

aaronrumple said:


> What did that conversion entail? I'm thinking of converting mine to underneath with either VFD or treadmill motor.



It depends on whether you have the late model headstock that was introduced with the models with 1/2" thick ways. If you do, it's a lot easier. If not, as in my case, it's much more involved. It's detailed in this thread with the meat of it starting here.









						New Caretaker of Two 12” Craftsman Lathes
					

Well, I'm back at it. I commented earlier about building a stand and a possible under drive countershaft conversion. I located the parts to do the conversion and a complete Craftsman lathe cabinet with drive assembly for a reasonable price, so off I go. It was my Grandfathers, Father’s, and...




					www.hobby-machinist.com
				




Best,
Kelly


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## wa5cab (Dec 13, 2020)

Actually, as I wrote earlier, if you have the late model cabinet and the drive components that are attached to the cabinet, but have any Atlas built bench model lathe except a 6" or 9", the only other things that you need to make it a bolt-together conversion are the 2-groove spindle pulley and two A42 belts.  The 2-groove pulley is a drop-in replacement for the 4-groove conical pulley used on the spindles of all of the bench model 10" and 12" lathes, whether 3/8" or 1/2" bed.

I will also mention that Atlas built in very small numbers a model 12700 which is identical to the 3996 and 101.28990 except that the cabinet and door are wider, with the two 4-groove conical pulleys mounted inside of the cabinet instead of on the outside of the left cabinet wall under the external swing-out cover.  It was apparently intended for use in schools with the students not being able to chop off their fingers without an instructor with key standing by.  It had the misfortune of being introduced at about the same time that most four-year high schools in the US were dropping all of their Shop and Home Economics classes in the interest of "saving money" and "college prep".  So very few were made or sold.


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## kcoffield (Dec 13, 2020)

wa5cab said:


> Actually, as I wrote earlier, _if you have the late model cabinet and the drive components that are attached to the cabinet_, _*but have any Atlas built bench model lathe except a 6" or 9", *_the only other things that you need to make it a bolt-together conversion are the 2-groove spindle pulley and two A42 belts. The 2-groove pulley is a drop-in replacement for the 4-groove conical pulley used on the spindles of all of the bench model 10" and 12" lathes, whether 3/8" or 1/2" bed.


I'm probably misinterpreting what you're saying here but unless you mean the entire lathe when you say _and the drive components that are attached to the cabinet, _I acquired the cabinet and drive components separately and I can tell you with certainty that there is no way my late 1940s era 12" is Craftsman (101.07403) could be converted to under drive with just the 2-groove pulley. There's absolutely no way the headstock casting could accommodate bottom exit of the belts, and certainly not placing the back gears underneath the spindle if that is part of the desired conversion. Also, near as I can tell the spacing between the bed ways is not wide enough to allow that belts to pass through under the headstock. I had to mill mine wider in that location to clear both the back gear and the belts. Weren't these features on the bed introduced around the same time as the first cabinet models?......and 1/2" ways?

The other thing I don't fully understand is the need for the _two grove _pulley......of course you don't need the other three steps but why two instead of one groove? The two groove pulley is the same diameter as the smallest step on the 4-groove pulley step at 3" so you already have several drive combinations that have the same belt/pulley contact area with a single belt but when you put two 3" pulleys you need two belts???

Best,
Kelly


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## wa5cab (Dec 13, 2020)

OK.  First, for many years, I used to every now and again ask for a bottom view photo (from outside, inside or both) of the headstock castings from various models of the 10" and 12" Atlas and Craftsman lathes.  I quit asking a few years back but No One ever responded with any photos.  But, I never said that there wouldn't be any modifications that had to be made to either the headstock casting or the bed, just that the parts were all usable.  I also did not say that there would be no hole drilling and/or hole plugging required in order to bolt the bed legs to the cabinet and oil pan.  There will at the very least be one hole to plug as the left leg on the Atlas 3991 and 3996 (equivalent to 101.28970 and 101.28990) has three mounting holes for attaching to the cabinet and is different from the right leg.  Whereas the 10F at least uses the same leg on both ends.  I also do not know whether the four holes equivalent to the four in the 10x36 10F and Craftsman equivalents are in the same relative locations (although that would probably have been easier if they would fit than putting them somewhere else).  So it is at the moment unknown exactly how many holes might have to be drilled and/or plugged.

As to why the 4-groove cone pulley was replaced by a 2-groove pulley for two of the same belts instead of a single belt and groove, I don't know.  But three possible reasons are (1) both grooves obviously had to be the same diameter if they were going to have two belts in place, (2) The pulley had to be the same LOA as the 4-groove in order to replace it without having to add several additional parts.  The hypothetical spacer would have to be keyed to the 1 or 2-groove pulley in order for the direct drive pin to work which would have cost more, (3) having only one belt on such a long pulley looked funny, (4) your guess is as good as mine but I'm voting for #3.  I will mention that it was good for me that they did have two belts as my 3996 was incorrectly assembled at the factory with the right-hand belt rubbing up against the wall around the belt pass-through cutout in the oil pan.  I did not notice it until several months later, by which time one belt was about to fail.  I moved the 2-groove jack shaft pulley all of the way to the left so that the right jack shaft groove lines up with the left spindle groove and the belt was well clear of the sharp edge of the hole in the drip pan.  And it has been working that way for the past 39 years.

Anyway, I will post another request for photos of the bottom of the Atlas 10" and early Craftsman 12" headstock.


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## wa5cab (Dec 13, 2020)

If I didn't make it clear, look at the bed page in the 3996 manual in Downloads.  It clearly shows the cutouts in the front and rear ways to clear the belts.  Otherwise, the only other significant difference between the early and late bed castings is the thickness of the ways.  The distance between them and probably the total width is all the same.  The later tailstock is different and the base is different but the two pairs  are the same width.  You could if you needed to run the early 12" tailstock on the late bed or vice versa.  I have both the early lever operated tailstock and the early turret tailstock and both fit the late bed.


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## kcoffield (Dec 13, 2020)

wa5cab said:


> Anyway, I will post another request for photos of the bottom of the Atlas 10" and early Craftsman 12" headstock.



I still have the old headstock. So as not to Hijack this thread, if you post a call for headstock pictures I'll detail the differences I'm referring to. As far as the bed casting mods, post #15 of this thread has a link to my build/conversion thread that shows the milling necessary. The belt reliefs need to be milled in both the top and bottom webs of the older style bed castings. Since I converted to the modern headstock  casting with the back gear under the spindle, the larger gear on the back gear protrudes below where the headstock casting lands on the lathe ways so an even wider relief needs to be machined in the older style bed casting to accommodate that feature. These mods are clearly pictured in the link. When I bought the cabinet, I also acquired the bed feet/risers from the cabinet 3996 style lathe. If I hadn't done so I would have also had to mill belt reliefs in the older style bed feet and if I recall correctly they may have a different mounting location to the drip pan.

If you look at the very first post of the thread in the link, there is a picture of both lathes, and I think they were manufactured within a year or two of each other. I've seen a few Atlas/Craftsman lathes but never paid close attention to them. These are the only two I've ever owned and the only one I've had apart. I also had modern headstock part and am familiar with the differences between those two models but don't know squat about the rest. The 54" bed lathe I still own is complete and completely original and a nice example. It has the same headstock as the 42" bed lathe I modified......

For the Original Poster of this thread, I guess my lathe is now a Frankenstein as well, but it's my Franky and I can assure you _"it's quite alive"_ and will perform well by the time I'm done. I wouldn't worry too much about the mix of parts if it performs well.

Best,
Kelly


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## kcoffield (Dec 14, 2020)

wa5cab said:


> OK. First, for many years, I used to every now and again ask for a bottom view photo (from outside, inside or both) of the headstock castings from various models of the 10" and 12" Atlas and Craftsman lathes.


I posted in your recent thread requesting such.








						Request for photos of the bottom of the Atlas 10" and early Craftsman 12" headstock.
					

Request for photos of the bottom of the Atlas 10" and early (i.e., 3/8" bed) Craftsman 12" headstock.




					www.hobby-machinist.com
				





kcoffield said:


> ......There's absolutely no way the headstock casting could accommodate bottom exit of the belts, and certainly not placing the back gears underneath the spindle if that is part of the desired conversion.


Robert, I'm going to have to take back part of what I said above. It does look _possible_ to cut a window in the old style headstock casting for bottom exit belts. Whether it's _advisable_ may be another matter because it may compromise the structural integrity of the headstock, but you need at least 3 1/4" and better 3 1/2" opening for belt clearance from the 3" 2-groove pulley. If you mounted the headstock on a mill with along cutter, you could punch a hole approximately where shown below. You would also have to cut similar reliefs in the bed was and bottom rib under this location on the headstock.






Now, placing the back gears under the spindle is another matter. You need to cut away so much of the headstock it would certainly be compromised and you really don't have much material for the back gear shaft and then you would need an engagement mechanism for the back gear and there just isn't room so even though you may get the belts out the bottom the back gears would still....well, in back.

-My 2 cents

Best,
Kelly


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## wa5cab (Dec 15, 2020)

OK  Thanks.  As I wrote earlier, I never expected that anyone would attempt to relocate the back gears underneath the spindle.  Even ignoring any detrimental effects of removing that much metal, it seems an awful amount of work for zero gain.  I suppose that it would make it possible to use the late 12" bench type countershaft assembly, which is probably stouter than the 10" horizontal one.  But there would be no benefit for the back gears.  

On the other hand, the cutouts for clearing the two belts would be relatively simple.  The most difficult part of it would be figuring out where to cut.  If the 1/2" bed is present, the bulkhead cutout would be the same size as the bed cutout.  Except I would makke it longer by 1/2 or the cutter diameter rather than fighting to make square corners.  The 1/2" bed would be the better choice if available and in good condition.  But to use it, you would also need the carriage and tailstock assembly.  And the early 12" headstock and countershaft would probably be slightly the better choice rather than the 10" as not only would you not need to make the riser, but the 12" countershaft would be almost a drop-in as it mounts to the lathe, not the bench or table.


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