Atlas 10 questions regarding chuck and runout

And if that isn't enough chuck information, there's even more when you get to fitting a new chuck to your old lathe :cupcake:
-Mark
 
Naw. . . Not really. The spindle nose is threaded for 1-1/2X8. Unless it has been modified. . .which is unlikely. There are (were) many chucks sold with backing plates already threaded for that size. It is a fairly common nose thread for middlin' size lathes, particularly American made "old iron". If the chuck and the backing plate are acquired seperately, it becomes a bit more difficult, but not that much more so. But it does complicate the knowledge base needed by a beginner. He had enough sense to get his hands on an older, basic machine and clean it up so is definately not a bozo loser. Just needs a little help now and again.

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I am reading through all this information and I am trying to figure out what I need to do? Essentially, I will probably only use this lathe for making rod building components which are usually small and light weight soft metal, german silver, aluminum etc. So early on we discussed that the 5 inch chuck is to big and won't work best with 1/4 and 1/2 inch projects. So, rather than trying to make the original chuck work shouldn't I just find a better chuck to use with the lathe? I just need a smaller chuck in good condition to solve this problem so that I can continue to learn how to use my lathe.
 
Bill, I just found 2 of the missing chuck jaws, with the longer step towards the center. Now I am wondering how to find another jaw that will complete the set? Any ideas? So your saying the 5 inch chuck is the right size for what I am trying to do with the lathe? The chuck reads, Union Mfg. 5 in., No. U 435
 
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Sir;
There are a number of options available to you. Some chucks were built to a standard for jaw fitting. You might find a set of jaws that would fit. I would be sceptical of replacing only one, of trying to get near zero runout with one odd piece. Another option would be to acquire a (used) chuck and just replace the existing one. If possible, find the same chuck so you could share backing plates. Swapping inside to outside bodies would be cumbersome but doable. Even possibly using the jaws without changing the chuck body. That would be a matter of how close you came to finding the same chuck. These options would all be contingent on finding parts that would interchange. That could get real expensive real fast and you might find yourself with a pile of unusable parts and still facing the original problem.

Now, to digress for a few and talk about chuck sizes. As far as "old iron" lathes go, the Atlas 10", any model, is considered a "light weight" as far as industrial machines go. There are many the same (M/L) size, the Atlas is toward the light end of that spectrum. My machine is a Craftsman 12(X36) which is basically the same machine on "riser blocks". An excellent machine for occasional "light" work, not so good for production work. It was acquired from a cotton mill in S. Carolina. Indirectly, but that was the original purchaser. Mine came with the same chuck as is on yours, but with "inside" gripping jaws. Chuck sizes go up from there, with "shipyard" and rolling mill lathes having chucks many feet in diameter. Many such lathes have smaller chucks that fit the large ones with "blind" spindles. Small chucks for small work. . .

I have a couple of other lathes and mostly do model(H-O Trains) work. I sometimes get into other work repairing "stuff" and the occasional odd "big project". I have a Grizzly 9X, a mini 6X, and (used to have) a UniMat DB-200, basically a jeweler's lathe at (3") 75mm. The Grizzly G-1550 has the same spindle threads as the Craftsman(Atlas), 1-1/2X8, and I find myself more comfortable with the 4 inch chuck for personal reasons. Mostly because it was new and had low runout from the factory. I also have a 3 inch 3 jaw from the UniMat that I have "adapted" to the much larger machines. But to make such an adapter requires some advanced knowledge. But something I would not recommend for a beginner. Not that I am an advanced machinist, I'm an electrical engineer. But hobby machining is necessary for other hobbies as well. I also have larger chucks, both an 8 inch and a 9 inch. Both 4 jaw independent and both very cumbersome (heavy) to deal with.

The bottom line here is that a smaller chuck is available, from the parts list for a smaller machine. But lucking into one is about as rare as finding the odd jaw for your chuck. Most Chinese lathes are threaded for metric, M39X4. Grizzly and Jet are two I know of that (in the past) did manufacture a lathe threaded for 1-1/2X8. I don't know if parts are still available, but it could be worth a try. Otherwise, I would recommend eBay or the like to acquire a replacement, looking for a 4 or 5 inch, with threaded back plate. A mini, some 3-1/2 inch diameter is available. But that small doesn't use a backing plate like the bigger machines. They could be fitted, with sufficient work, to a larger machine. I personally would recommend against it unless there was an over-riding need for such a small chuck.

Any larger on your machine would be asking for trouble. That would take some time at best, looking for something at a price you would pay might be even longer. What ever you end up doing, make sure a backing plate is included or can be acquired for your spindle nose thread. At this point of your (assumed) knowledge, I would recommend against replacing a single jaw on your existing chuck. The wear, hence runout, could well be atrocious. Or possibly a drop in. If you do replace them, replace all three as a set. It is possible to grind to fit a single jaw, but that is something that requires a little more knowledge of your machine.

I find myself drifting into preaching or teaching mode so will back out for now. I will follow along anon and answer any question you have. But I've talked far too long now and will drop out.

Bill Hudson​

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Thanks Bill, I sure appreciate the help with this! I think I have a better understanding of what I need to do. What I originally thought was that I needed a smaller chuck for the smaller work but now I understand that its the smaller jaws on a 4-5" chuck that is most important. I would like to use the chuck that came with the machine but maybe that's not possible now? I'll just have to see what my options are, I just want to be able to use my lathe.
 
A 5" would be a nice size for your Atlas 10" Also you might want to consider a collet set in addition to a chuck
-Mark
 
markba633csi said:
A 5" would be a nice size for your Atlas 10" Also you might want to consider a collet set in addition to a chuck
-Mark
Click to expand...
A very good suggestion, Mark. Especially for the anticipated small work below a half inch. To acquire a collet chuck would also buy time to watch for a suitable 3 jaw. I have a small collet chuck(ER25), but use it so seldom it never occured to me as a possibility. The lathe will accept a MT-3 taper in the headstock. The through hole is a fuzz over 3/4 inch. An ER25 or ER32 would be suitable for long stock. A larger size would work but wouldn't feed large stock. That's one of the calls that the individual has to make. It can get expensive later if the buyer gets too small or too large. To find one with the backside threaded for a drawbar would be preferable. In the range of anticipated use, a hollow drawbar can be finagled, allowing long stock to be fed through.

Further, while scrounging around for small tooling, I have seen several small (3-4") 3 jaw chucks with a straight shank. I don't remember specifics, particularly pricing, just something that caught my eye. To mount such a chuck in an ER chuck would reduce accuracy to some extent. But a 3 jaw is not known for accuracy to start with. It definately would expand the options while looking for a solution to the overall problem. The one that comes to mind is a 2-1/2 inch, threaded for M12X1, that has a straight shank. It's what I used to make a MT-3 adapter. (MT-3 to Jacobs taper to M-12) It uses tommy bars rather than a key so is suitable only for light work. But a possible "drop in" so;ution.

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