Source For L5-35-54a Lead Screw

mrjbinok

mrjbinok

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I am looking for a replacement lead screw for my Craftsman 101.07403 12x36 lathe with a 54" bed. The only thing I have found is from Sears Direct new $800.00+. Ebay has come up with nothing for the last week. I would like a new part for the least amount of wear, but even a good used part would be a big improvement for what I have.

Is there ANY other vendors out there that makes and/or sells replacements?
 
What is the OD of the thread, thread pitch, is it a right hand thread or left hand? Last what is the overall length of the thread on the screw as well as the overall length of the screw?
You may have to buy a precision piece of all thread from Mc Master Carr or Keystone, or one of the other places out there. The class of thread you will need is a Class 3C, not 2G or 2C. You can look at the Machinery's Handbook for explanation of the class of fits for Acme threads.

Edit: You may have to buy a length of all thread and splice it into the existing screw to replace the old section of thread.
 
I am by no means a seasoned machinist. I have been making various parts that I have needed for the last 10 years with a small Harbor Freight mini-lathe, but my experience is limited and shop equipment is limited.

The part number for this lead screw is L5-35-54A. Looking at the part, I see that it is a 8 thread per inch 3/4" diameter Acme thread. Overall length is 51 3/4" with the threaded portion 40 1/4". I think that it is left handed thread, which is confusing, because the split nuts for my lathe (10F-12) that I see listed on Ebay are right hand threaded.

I just sent an email to Clausing to see if they have anything I can use.... wait and see what they have to say after the weekend.

Looking at McMaster-Carr, they have threaded rod in the 3/4"-8 left hand thread that I would need. I would be able to turn the ends for fit, but I have no capability to mill the keyway slot that runs the full length of the part. The only rod they have listed in a 3/4"-8 is 1018 Carbon Steel (http://www.mcmaster.com/#lead-screws/=12tfcc8) and I don't see any reference to the Class ratings mentioned above.

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.

I'll try to get some pictures to upload in the morning.... might help to clarify what I currently have.

Thanks for the suggestions.
 
4gsr said:
What is the OD of the thread, thread pitch, is it a right hand thread or left hand? Last what is the overall length of the thread on the screw as well as the overall length of the screw?
You may have to buy a precision piece of all thread from Mc Master Carr or Keystone, or one of the other places out there. The class of thread you will need is a Class 3C, not 2G or 2C. You can look at the Machinery's Handbook for explanation of the class of fits for Acme threads.

Edit: You may have to buy a length of all thread and splice it into the existing screw to replace the old section of thread.
Click to expand...

I'm not finding the information on the "class of fits for Acme threads" in the Machinery's Handbook. Can you give me a page number and edition number you are using?
 
Sometimes you can just TURN THE LEADSCREW AROUND. Modify it to work in the backwards position. You will in effect have a new lead screw as they only get worn most often in a limited area near the chuck. Most threads are short,after all.

About the half nuts: I was tempted to make a new set of half nuts out of bronze,as I had to replace the Zamak ones too often. The job would not have been very complicated,and could probably have been partially done by silver soldering the rectangular "sliding" part to a round piece for the threaded portion. I mean making a NEW sliding part,NOT trying to silver solder the ZAMAK original part!!:)

I'd have used an angle plate fixed to the face plate,with the half nut project secured for boring and threading. Then,sawing apart later.

The wisest thing to do would have been to first make a dummy piece of lead screw up to match yours,and make sure that it threads nicely before taking the new half nuts off the angle plate.
 
4gsr said:
What is the OD of the thread, thread pitch, is it a right hand thread or left hand? Last what is the overall length of the thread on the screw as well as the overall length of the screw?
You may have to buy a precision piece of all thread from Mc Master Carr or Keystone, or one of the other places out there. The class of thread you will need is a Class 3C, not 2G or 2C. You can look at the Machinery's Handbook for explanation of the class of fits for Acme threads.

Edit: You may have to buy a length of all thread and splice it into the existing screw to replace the old section of thread.
Click to expand...

4gsr and george wilsons solution may be the best.
As 4gsr has identified threaded rod comes in different levels of precision and accuracy. Be sure to get what you are looking for.
And yes it is possible to do this yourself.
Or, hire it out....
Check back here at HM if you decide to tackle it yourself there are many here who will walk you through the project.

Daryl
MN
 
If your thread was right handed, you could get a good condition lead screw from a 9" Model A or B South Bend lathe and splice it in.

I'm a little puzzled why a lathe manufacture would put a left handed lead screw on a lathe?
 
4gsr said:
If your thread was right handed, you could get a good condition lead screw from a 9" Model A or B South Bend lathe and splice it in.

I'm a little puzzled why a lathe manufacture would put a left handed lead screw on a lathe?
Click to expand...

My BAD!!!! I'm going to have to teach myself not to do anything technical (like identifying threads) at 3AM. It is RH.

Hopefully I'll hear back from Clausing today or tomorrow and see if they can help. In the meantime I'll look for the South Bend part and see what would be involved with splicing. My shop experience is limited, so it may be more than I can accomplish at this point. I'm pretty good at figuring out ways to get to where I want and not afraid to look at something new.... a few years ago I tackled a 1972 Harley that was a barn find basket case and I put back into near showroom condition.... with no prior experience.
 
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