# Another Atlas 12x36 Acquisition



## Smudgemo (Nov 3, 2012)

I joined this forum because I picked up an Atlas 12x36 last weekend and hope to pick up on what others are doing with this lathe.  I've got a little machine shop experience at a local industrial art school making fixtures to build bicycle frames, and I'm very excited to get acquainted with this machine.  Seems like it's close to being a "cream puff", but I'm no expert.  I want to replace the desk it's mounted on with something more solid, but seems otherwise ready to work.  

It came with 3 and 4 jaw chucks, face plate, and a little tooling.  More tooling would have been great, but it doesn't seem to need much attention.

Thoughts?  Suggestions?

Best,
Ryan


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## davidh (Nov 3, 2012)

good lookin machine.  i have an earliefr version with manual speed changes.  it has done a lot of little projects for me and im certain it will continue to do a bunch more.  it looks like the wood its mounted on is the same as the one i have that mounted on its orig. legs.  i also made a larger more sturdy bench for mine. . . double 3/4" plywood top, with masonite added to make it easy to clean. . . i really love mine. . .i have taper attachment, milling attachment and some sort of collet arrangement that i have never tried to use.


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## wa5cab (Nov 4, 2012)

Ryan,

From what's visible in the two photos, it does look to be in quite good condition.  It looks to be a Model 101.28910, one of the final four models that Atlas built from about 1968 through 1981.  The nameplate should be on the right end of the bed.  It's equivalent to the Atlas 3986.  I have the 3996 which is the cabinet model.  The thick wood base it is sitting on appears to be original, but without the standard cast iron legs.  There was a drip pan made that sat on top of the wood.  That or a reasonable facsimle would be a worthwhile addition.  If you did not get the Craftsman manual with it (the brief setup, operation, and illustrated parts list), check the list's Files section.  If it isn't there, I can send you a PDF copy.  Photos aren't great but are usable.  The other manual that would have originally come with it is the Manual of Lathe Operations and Machinest's Tables.  A worthwhile addition, too.  About 3/4" thick, it was still available new from Clausing last time I checked.  For under $25.  Of course, it says Atlas on the front cover instead of Craftsman but otherwise is the same.  They also turn up on eBay usually for more $ but are more likely to be earlier editions all the way back to 1938!  The current edition will match your machine.

Robert D
AKA Gunner


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## Smudgemo (Nov 5, 2012)

Thanks, guys.  
The model number is 101.28910, and the ways appear to have been cast in '65.  The seller gave me a bunch of scanned documents that I  need to go through.  Supposed to be more than everything (and there are a lot of documents to go through), but I'll pipe up if I could use something.  

We also struck a deal on an import QC post and a like-new Atlas milling attachment, so the capability will be expanded considerably.  I'll be mitering tubes for bicycle building hopefully soon (finished work is in the bike/motorcycle forum.)  I just need a collet system and I'd like to find a steady-rest that doesn't cost a fortune.  

Eventually I'd like to put it on a stand or something smaller and more sturdy than the desk, but it should work for now.

-Ryan


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## wa5cab (Nov 5, 2012)

Ryan,

OK.  Hopefully you'll find at least the owner's manuals on what you have in the scanned stack.

I forgot to mention earlier that before you try to actually use the lathe, first its stand and then the lathe need to be leveled.  If you just set the stand on an average floor and then bolt the lathe to the stand, it isn't likely to be anywhere close to level and will probably be warped slightly.  Look at the other most recent thread here for further comments.

What size tubes do these bicycles use?

Robert D.


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## Smudgemo (Nov 5, 2012)

Thanks for the warning, Robert.  I'm borrowing a level and taking advice from the teacher at the local industrial arts school.  He's a machinist by trade, so I'll be in good hands with setting this thing up correctly.

Tubes for the front triangle are generally between 25.4 and 37 mm depending on what I'm making.  Head tubes will go as much as 1.6mm for the walls, where a "normal" 4130 frame tube is .9/.6/.9 or .8/.5/.8, but some of the fancy heat treated tubes can go as thin as .5/.4/.5.  When a fill-up of my Subaru is $40 or so, it's very satisfying to be headed down the road using no fuel on a vehicle I made in my garage.

-Ryan


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## wa5cab (Nov 6, 2012)

Ryan,

OK.  As the other thread just touched on, precision levels are a bit on the expensive side for something you may need to use only once in a decade.

On the collets, the hole through Atlas 12" spindles is only 25/32".  So you won't be able to pass any of your tubes through the headstock.  And the "native" collets for the machines, 3AT, have a capacity limit of 17/32".  The largest size collet (and probably, for lathes, the most common) for which I know that you can buy closers to fit the Atlas is the 5C.  It has a capacity limit of 1-1/16".  So a 1" 5C collet will hold your 1" tubing.  And you can pass the tubing through the collet and closer up against the spindle nose and be able to work on tubes up to about 3' long.  You can also buy, for tube diameters larger than 1-1/16", what are called step collets, which have oversized heads that you can bore part way through.  Max length that you can work on will be less than 3' by the length of the closer.

On the 5C collet closer, that I know of there have been two types made to fit the Atlas.  Royal and someone else made a front mounted lever operated closer that are somewhere between uncommon and rare.  But you might be able to find one of those used.  Until recently, I had one of the Royal ones.  Several Chinese companies are making the other type that is operated with a T-handle square nose key like a 3-jaw chuck.  These are available from several US vendors and on eBay for typically between $180 and $350.  The less expensive ones are usually sold as plain or flat back and you would have to make the back plate.  Which you don't want to do.  So be sure if you buy one that it comes with a back plate to fit a 1-1/2"-8 spindle nose.

On the steady rest, you aren't likely to find one for the 12" for under $100.  The originals came in two styles.  The early type (up through sometime in the 1960's) have a one-piece body that encircles about 250 degrees of the work piece.  To load or unload them, you have to disturb the setup by retracting the top jaw or finger.  Which is undesirable for several reasons.  The late ones have a two-piece body.  The top is hinged at the rear and can be opened without touching the jaw settings.  There are several of the early type on eBay tonight but the only late type I see is an aftermarket unit.  It looks well made and reasonably priced ($150) but unfortunately will not take original Atlas jaws.  With the thin wall tubing you described, I would suggest a set of aftermarket ball bearing jaws.  And the aftermarket steady rest listed doesn't look like it will take the roller jaws currently available.  

There is one other hinged top steady rest on eBay tonight with the word "Atlas" in its title, but it won't fit any Atlas-Craftsman that I ever saw.

Robert D.


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## Smudgemo (Nov 6, 2012)

Thanks, Robert.  That's good information.

I don't need to pass the tubes through a collet, though.  I want to hold end mills and arbors for hole saws for milling and mitering, I won't need a very large capacity collet.  I intend to mount the tubes in square blocks (or fixtures in the case of tapered tubes for the rear triangle) in the milling attachment.


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## wa5cab (Nov 6, 2012)

Ryan,

When you said that you needed some sort of collet attachment, and then a steady rest, I assumed your intention was to hold the tubes in the headstock and steadyrest and rotate them. I did wonder how you could miter the tubes that way.

There are two ways to hold cutters in the headstock, chucks or collets/cutter holders. Chucks are generally less desirable for a variety of reasons. 3AT or 3C collets and a draw tube will work but for just holding cutters have no advantage over 3MT collets or cutter holders and a drawbar. And will usually cost more than a 3MT setup. Clausing sold a 3/8-16" drawbar, and a 3MT cutter holder set. The drawbar was still available 6-8 months ago and was no more expensive than several original or aftermarket ones on eBay at the time. Their 3MT cutter holder fits the spindle nose and fits 1/2" dia. shank cutters and wasn't very expensive. But it locks the cutter with a set screw and the cutters really should be of the Weldon type, with a flat on the side of the shank. They also sold a set of four reducing bushings for 1/4", 5/16", 3/8" and 7/16" dia. cutters but the bushing set was expensive. You can also buy set screw type 3MT cutter holders that fit various diameter cutter shanks but most are not drilled on the back end for drawbar. Avoid those. When, not if, one comes loose during an operation, you will not like the results. 3MT collets, either in sets or individually, are readily available. They will also hold drill bits. Their only disadvantage compared to cutter holders is that when you loosen them in the spindle, you also loosen the cutter, which can then move axially or even fall out. But the collets are probably the least expensive option if you use a variety of cutter shank diameters.

You should also get a spindle nose thread protector, a short collar that screws onto the spindle nose after you remove the chuck.

Robert D.


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## Smudgemo (Nov 6, 2012)

So correct me if I'm wrong, but it sounds like ordering 3-4 common size MT3 collets will be least expensive, but plenty versatile for my needs for now.  

The draw bar options appear to be 
1. buy one
2. get some thread-cutting practice by cutting one from a length of hex rod on the lathe
3. or perhaps something as simple as a length of all-thread with a washer and a couple of nuts jammed together (or since the torch for bike building is handy, maybe something a bit fancier where I braze a nut in place.)  Feel free to discourage this one if appropriate.

Any idea how long the drawbar needs to be so I'm in the ballpark?


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## wa5cab (Nov 6, 2012)

Ryan,

Although 3AT and 3C collets normally come in 1/32" increments and 3AT at least can be found in 1/64" increments, 2MT and 3MT collets commonly come in 1/16" increments.  So decide what milling cutter and drill diameters you need and buy them with 1/16" increment shanks (and you will need to use single-ended milling cutters).  Not much that you can do about drill bits below 1/4" except to use a headstock drill chuck.  Buy 3MT collets with 3/8"-16 drawbar threads to fit the cutters.

1.  I would buy one, myself, as I have other things I need to do.  But...

2.  Make the draw bar out of 3/8" round stock, not hex stock.  It needs to be round at least on both ends, round stock is cheaper than hex, and there is no benefit to having it hex in the middle anyway.  Cut the threads with a die nut.  You only need about 3/4" threaded on the collet end.  If you can borrow a tailstock die nut holder, you can use that and be able to say you did it on the lathe (in back gear).  The Atlas has no brake, so if you try to thread the rod with a single point tool, you would probably need to cut a relief groove for the cutter runout or the main practice you would get would be in checking your blood pressure.  

3.  You could make the rod out of all thread but if you are going to make a drawbar, you may as well make it look decent.  And you will be less likely to bend the solid rod than the all thread.  Do not use a hex nut and wrench.  If you do, you will soon come to hate it.  And the first time that you forget and leave the wrench on the nut and turn on the motor, you will really hate it.  Plus, you have to have something on the left end to hit when you want to remove the collet from the spindle (I use a piece of 2X4 oak block about 6" long.

Put a handwheel on the left end.  Diameter between 2-3/4" (factory) and 3-1/2" (an aftermarket drawbar that I have).  The left face of the handwheel should be approximately in the plane of the left vertical face of the gear cover up to an inch or so to the right of that.  Between the left face of the spindle and the right face of the handwheel hub you need a spacer/thrust bearing.  OD 1" to 1-1/4".  ID 3/8".  Length depends on design of the handwheel.  Turn about 1/8" of the right end of the spacer down to a diameter of about 3/4" so that it is a slip fit into the spindle bore.  This centers the drawbar in the spindle.  You will see some spacers (including factory ones) for both drawbars and drawtubes that are beveled on the end instead of having a reduced diameter pilot.  The latter works better all around, both when hooking up and tightening the collet, and when removing it from the spindle.  With the beveled spacer, releasing the collet is a two hand operation.  After looseining the hand wheel about two turns, you need to hold the beveled spacer into the slight countersink in the left end of the spindle while you hit the handle (and the knuckle of your right index finger) with a block or something.  The piloted spacer will stay in place all by itself.

The length from the face on the left end of the spindle to the right end of the rod should be between 8-1/4" and 8-3/8".  So the total rod length needs to be that plus an amount that will vary depending upon handwheel design.  

Robert D.


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## Smudgemo (Nov 11, 2012)

I finally got a chance to pick up the milling attachment.  I can't say for sure, but it looks like new.  



As for mitering tubes, this is the idea:



I ran a scrap tube through it just to see what would happen, and it appears to be successful.  Setting angles will be fairly easy.  I think the thing I'll need to figure out is how fast to run the cutter and what feed-rate works best with this thin-wall tubing.


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## wa5cab (Nov 11, 2012)

Yes, the milling attachment does look like it's had little to no use.

I would expect that Milwaukee has a web site.  Try that for a recommended RPM chart.  Or some of the other vendors.  That's a good idea to use a hole saw for that operation.  I sometimes use them for rapid diameter reduction on short workpieces that are going to have a hole through them anyway.

Robert D.


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## Smudgemo (Nov 23, 2012)

Hey Robert, 

Something along the lines of this?



It's been a few years since I last cut threads, and using a length of drill rod didn't make the job any easier.  But they seem to be acceptable and do indeed hold the collets.  I made the relief because it greatly simplifies the process.




I added a thrust washer and went with a cone shape for the centering part.  A set-screw holds against a ground flat on the rod, and I left it a bit long to have something to tap against to release the tool.




This is one job I won't miss doing by hand.  Slitting the ends of the forks or seat/chain stays for bikes with a hacksaw and files so the dropout fits snugly for brazing (this is just a scrap tube), and doing it at a 5-10* angle so you don't need to bend anything isn't easy.



I'm thinking of adding a snap-ring to hold the cone and washer in place, but I'm not sure how I'd cut a thin groove.  I must say that using the lathe to make a part for itself is pretty cool.

-Ryan


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## wa5cab (Nov 24, 2012)

Ryan,

Yes.  That looks like a pretty typical drawbar.  Except that I would have to cut off the rod flush with the left end of the handwheel.  Sooner or later, I would forget and reach around with my left hand to smack the handwheel to release the collet and put a bloody D-hole in my left palm.  :-(  Once you are satisfied with the thread engagement in the collets, I would drill and pin the rod to the wheel.  And not depend upon the set screw.  Or alternatively groove the rod for a circlip.

As far as a tool to make circlip grooves, I have for years used a grooving and cutoff tool made by Kaiser Tool Co.  They call it "Thinbit".  The tool holders come in various square sizes.  I use 3/8" square holders as that's what fits my QC holders.  The cutters mount in the end of the holders somewhat like replacable insert carbide tooling. but on the side instead of the top.  The cutters come in various widths and lengths.  For grooving you would use the shortest length and for small circlips the 0.029" wide one would probably work OK.  I forget what other widths they come in.  I use short or long 0.062" ones for parting off.  The short ones for tubing and the longer ones for solid.  They aren't what I would call particularly expensive.  Aside from choice of left hand or right hand, one tool holder fits the entire range of cutters.  So you could get by with only one holder if you don't mind the time it takes to change cutters.  The holders come in left hand and right hand  Unless you run it into the chuck, a holder should last forever.  Breaking off a cutter won't generally damage the holder (I've broken a few).  The tools are also useful for making O-ring grooves.

Robert D.


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