Source For L5-35-54a Lead Screw

I still haven't gotten pictures of what I have. The threads on this one are in REALLY BAD shape. In the wear area some of the threads are so badly eroded from rust that I am surprised that they will even feed at all. The two ends are quite different and different diameters, so swapping end for end could only be accomplished by cut/splice.

I'm not sure that the threaded rod I looked at from McMaster Carr will work for me. I'll need to get more information about the thread root diameter. On the rod I have, the thread root diameter is slightly smaller than what I would need to turn down to fit the left hand drive coupling...... again I would have to do a cut/splice.... not something I've done in the past.

I'm still working on a teardown of the carriage so I can see what else is needed, so I will get back to this in a day or two. So far the lead screw is the only major issue I've encountered.... mainly the lathe just needed a good cleaning, check and lube. Even the way's are even in pretty good shape, with barely detectable wear. Not bad for it's age..... timken bearings are marked 1945 and 1946.

Thanks to those that have offered suggestions. I now have something to work with and I'll post an update when I find a solution.
 
http://www.keystonethreaded.com/acme-threaded-bars.html Here you can see the different types of materials and thread classes available.
https://www.bing.com/search?q=keystone+threaded+rod+suppliers&go=Submit+Query&qs=ds&form=QBRE Here is some places you can purchase it.
Don't waste your time and money trying to use an alternate material or thread class. If necessary, have someone help with the splicing of the new threaded section into the lead screw, or build you a complete new one if the rust has damaged the lead screw in other places badly as well. The lead screw is one of the most critical parts of your lathe regarding producing accurate results.
 
Bob Korves said:
http://www.keystonethreaded.com/acme-threaded-bars.html Here you can see the different types of materials and thread classes available.
https://www.bing.com/search?q=keystone+threaded+rod+suppliers&go=Submit+Query&qs=ds&form=QBRE Here is some places you can purchase it.
Don't waste your time and money trying to use an alternate material or thread class. If necessary, have someone help with the splicing of the new threaded section into the lead screw, or build you a complete new one if the rust has damaged the lead screw in other places badly as well. The lead screw is one of the most critical parts of your lathe regarding producing accurate results.
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Thanks for the links. Since I am relatively new to machine work, the "Common Terminology" page they have give me a basic understanding to build on.

I got a reply back from Clausing this afternoon. They have the leadscrew new in stock for $700.00 vs what Replacement Parts.com has for $895.51. Not in a big hurry to drop that kind of cash, so I'll sit on this until I finish checking everything else on the lathe.

I live in a fairly small town and shop availability is an issue for someone to do the work needed to splice or fabricate a one-off part. I'll take some time to continue looking. I still have the carriage assembly to tear down and the tailstock.

This machine overall looks to be in good condition or possibly light use. Most everything else I've looked at for wear looks like it has been well maintained and kept oiled like it was suppose to be. The only other part that I have found with extensive rust was on the compound slide lead screw.... toward the front where you don't normally see it. I guess the PO's didn't see a need to keep the lead screws oiled up and didn't pay attention to the rust when it started.
 
Here are a couple of links to making a new leadscrew for Atlas/Craftsman lathe.
http://www.hobby-machinist.com/threads/cutting-a-key-for-an-atlas-lead-screw.18159/#post164094
http://www.machinistweb.com/forum/showthread.php?t=977

mrjbinok said:
A question about the full length keyway.... is it necessary for it to run the full length? It looks to me that it is only used on the left end of the rod to couple to the drive stud coming from the gear drive.
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The full length keyway is used for the powered cross feed. The part of the keyway that fits into the QCGB is a different size than the full length one. If you can live without the power cross feed you could just use a threaded ACME rod with the ends cut down. You would just have to remove the bevel gear with the key cast in it.
 
Current plan is to order a 6' length of the threaded rod and a couple shorter lengths of decent quality round bar on payday (Friday). I intend to turn the ends from the round bar to mate up with the change gear drive stud and the right bearing (bushing), and then cut the threaded rod to the length needed so that I can press the three pieces together, drill and pin. I have limited experience doing turnings that need a press fit, so I will use the excess rod and short pieces of the round bar to practice with to build my confidence. I figure that will be good practice for me, and also let me see how accurately I can put the newly rebuilt lathe to work. I'm pretty confident that when I am done, this lathe will operate as well as it did when it was new.... 70 years ago.

I have a new 6" three jaw centering chuck coming on Thursday and a couple other small parts for the tailstock coming on Friday, so that should be all I need to finish up with the rest of the lathe. I plan to check spindle runout later this morning and make another few adjustments. I've had the lathe for 30 days now, and I have completely gone through it. I powered up for the first time on Saturday and checked all the functions..... no smoke and it didn't blow up in my face!!

The guy I bought the lathe from in St. Louis is a working machinist and he has offered to cut the keyway for me and help with truing the rod once assembly is complete. Since the left piece and threaded rod need the 1/8" keyway cut full length and the right end does not have the same keyway (it has a smaller keyway for the keyed thrust washer on the end), I will have him do the keyways and final assembly.
 
I would not worry about getting press fits on your pieces. Ream a good concentric hole in one piece and turn a OD counter turn to fit the ream bore. Shoot for a tight slip fit, or in other words, tap fit with a small hammer. Loctite if you wish. Once assembled drill and ream a No. 2 or 3 tapered pin. one pin should be all you need for each joint.
 
Well the "Machine God's" are smiling down on me!!! I was able to find a used listing for the lead screw that I need on Ebay and was able to buy for $120 + $30 for shipping. It arrived Saturday and to my surprise, it is in almost new condition. I can't even see any evidence that it's been run at all.

Long story short.... my Craftsman rebuild is now complete and I have spent the last couple of days making chips. Many Thanks for those who offered suggestions.

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Now look for a QC gearbox. I have seen several on Ebay. You'll have to modify the leadscrew to fit the QC box,but it isn't hard to do.
 
I've been watching the QCGB's already. I have my feed speed set up for what I need with the change gears, and won't need to change any time soon, so for right now I don't have an immediate need so I'll probably wait a bit..... and enjoy having a decent working lathe for some projects that have been on hold for several months.
 
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