Initially, the only difference was that the headstock (still cast iron) and spindle were modified to take Timken tapered roller bearings like the 618 had. Sears discontinued the 101.21200 in 1976 or early 1977 and Atlas replaced the 3950 with the 10100 (which Sears never sold). The bed was originally the same as on the 618 except for the location of the tapped holes for the headstock and legs. As those were used up, they were replaced by what you have. The first 800 to 1000 or so used the same compound and tailstock as the 618. They have ball bearings on the spindle and a cast iron headstock. The first two models were Atlas 3950 and Craftsman 101.21200. All have 1"-10 spindle threads and are 8-speed (no intermediate countershaft). The 101.07301 is almost the same as the 618 made in about 1938 to 1940 except has sleeve bearings and 1"-8 spindle threads. The 618 and 101.21400 are exactly the same except for badges and nameplates, and both have 1"-10 spindle threads. The steady can even be as simple as a tight fitting hole in a block of hardwood clamped down onto the ways.The Atlas Mk1 (which was never actually called that during its lifetime) consists of the Atlas 612 and 618, the Craftsman 101.07301, and the Craftsman 101.21400.
#ATLAS LATHE 618 STEADY REST FREE#
This holds the left hand of the workpiece tightly against the taper and leaves the right hand end free to be worked on. With the right end of the work in a steady rest screw the faceplate the rest of the way on to the spindle nose. Using leather thongs (traditional but shoelaces will work!) tie the dog very tightly to the faceplate. A trick that I have used is to put a face plate on the spindle part way, a dead center in the taper, and a lathe dog on the left end of the work.
![atlas lathe 618 steady rest atlas lathe 618 steady rest](https://i.ebayimg.com/images/g/BL0AAOSwMWVgnvLt/s-l225.jpg)
If yes then think about a steady to the left of the saddle to support the work. If you just need 6”more or so check to see if running the saddle to the extreme right and fiddling with the compound and tool location will get you where you want.
![atlas lathe 618 steady rest atlas lathe 618 steady rest](https://live.staticflickr.com/2815/12269883616_baf00e2d9f_b.jpg)
Going much longer could upset that balance. I find my 618 to be not very heavy duty but it is well proportioned overall in not having any particularly week or strong spots. OK Ken, I see where you are going with this. Hope that makes Sence? - Ken H in AZ Knowledge is like manure, it won't do any good unless you spread it around. Once that's done I can grind off the sacrificial center and chuck the cleaned up shaft end (with copper protectors) in the 4 jaw, dial it in and clean up the rest of the roller shaft. But I may also just do the set up the way you proposed, weld up the old faulty center drill hole and then drill a new acurite center hole then MIG weld a sacrificial center into the new hole (since I need to turn the area that a dog would go for turning between centers) this will allow me to true up the shaft end.
![atlas lathe 618 steady rest atlas lathe 618 steady rest](https://www.georgia-market.com/Dalton-/Electronics-/Atlas-12-inch-lathe-steady-rest-pics_image.jpg)
I may be able to grind a tool that gives the extra clearance needed. Aaron, the boring head I have is an ancient Criterion, at it's max offset it just barely clears the outside of the shaft I need to clean up. It would likely be used more often for support than running out the saddle.
![atlas lathe 618 steady rest atlas lathe 618 steady rest](https://i.ebayimg.com/images/g/CP8AAOSw9DZg-KyZ/s-l64.jpg)
It's not something urgent but more of a upcoming project at this point. I don't generally do high precision work, stuff like cleaning up the ends of axels or light facing, knowing I could only take light cuts. Bill, I want to do the extension mainly to run the saddle farther out.