lead screw fits?

robert102653 · May 4, 2015

Hii i have a 1947 south bend 9A lathe with a four foot bed. it seems that this is a rare bed. I need a new lead screw for it and have not found a single one at any price. I am kinda stuck. Is this lead screw unique? Will the one from a heavy ten or a ten k fit? will anything but a 9A model A fit this lathe? ok thats the bad news the good news is i am proceeding apace with the soaking of the parts in the ZEP version of purple power. Man, this stuff takes off the grease and the paint as well. no need to strip the parts as they are already there. they are down to bare metal i cant get to painting them right away so i sprayed them all with WD40 to prevent rust. i know i will have to degrease them again but at lest now they are clean and swarf free. So far i have done the saddle and the apron and the tail stock. i am working on taking off the gearbox but i have to wait till the impact screw driver set comes in. I tried the screw driver and wrench method but no dice the screws wont budge.

Dobermann · May 4, 2015

A 9 inch South Bend with a 4 foot bed is not rare. I have one. I'm not sure why you're having trouble finding a lead screw. It may not help you but the 9 Workshop, 9 Jr., 10K and Heavy 10 all use the same diameter and pitch lead screw. The lengths certainly vary from machine to machine even with the same length bed. Someone on this forum is bound to have one. Failing that, check with Plaza Machinery (PLAZA MACHINERY,USED MACHINERY, METALWORKING MACHINERY, WOODWORKING MACHINERY) You have to be a little patient with Plaza because Joe is sometimes slow to answer emails. But you can rummage through his listing of parts and probably find what you want.

abarnsley · May 4, 2015

Just order up generic Acme lead screw stock. Available from many sources.. Manufacturer of Custom Roll Threaded Products - Cleveland, OH

No machine/lathe threading required. Do it on lathe, it can repair itself..

Cut Acme thread stock to length, turn shoulders, ( A sleeve can be silver brazed on if needed) drill for pin/s if needed, cut keyway, etc

Ground thread Acme rod, is overkill/unneeded on a SB 9 in lathe...

Pretty paint will not fix the worn bed and carriage, or sloppy tailstock ram.....

stephen thomas · May 4, 2015

I agree with Mr Barnsley that as a machinist, it is dumb to let whether a simple, non-hardened, non- special ground part is available off the shelf govern you life.

I just made a leadscrew for a 54" bed 10K, though; and it is a little more involved than he notes

I chose to make a complete stub shaft that goes in the gearbox. This part was made out of 4140 prehard, and has the bearing journal, the threaded end for the nut, the step& shoulder for the gear location, the keyway, and the shoulder as the thrust surface on the outside of the gearbox all in one piece. It is also carefully bored on center 9/16" ID into the shoulder end (I made the shoulder longer than stock which interferes with nothing including the apron).

Then I took a length of rolled precision leadscrew (more than adequate for the task) from ROTON. Set up through the headstock in second op Hardinge, I manually turned parted it off, and turned and jounrnal on one end to fit the TS end bearing, and on the other a stub projection to go in the stub shaft already made. Then i used a heat gun on the OD of the stub shaft, inserted the end of the new screw, and shrunk them together. When it cooled, i put a small taper pin through for good measure.

You face 2 challenges. One, Roton has a minimum order of $80. So even if your leadscrew only costs ~$50 or $55 for your 4' bed, you still have to either buy something else or send them the balance anyway.

Next, a 3/4" OD leadscrew will not fit through the spindle of your 9" IIUC (someone may correct me here?) If it will, or if you have another lathe to use, be very careful setting up and centering. I used a 4 jaw chuck on both ends of my second op, for intance; and it took a while to dial in.

Oh, Yeah, your 3rd challenge out of the 2 I mentioned

is to cut a slot in it for the rack drive geartrain. This can be done in steps on a horizontal or even vertical mill. I would surely use a slotting cutter (saw type) even if using a vertical. In my case I planed it. The screw, no matter who made it or where sourced, will take a nice pretty bow after the slot is milled. Part of the untold enjoyment of this immersion experience is to practice carefully straightening it to a good flat surface.

In summary, you are a wuss to be buying a leadscrew when you could be out in the shop spending untold countless hours of quality time & no small sum of $$$ for a cutter, leadscrew blank, and a stub shaft to make it. But I would not fault you for that decision, having enjoyed the experience for an extended period myself.

I have a perfectly good 4' leadscrew from my old bed, but not willing to part with it, yet, given my renewed appreciation for what it takes to fit a new one....

rusty old tools · May 4, 2015

stephen thomas said:
I agree with Mr Barnsley that as a machinist, it is dumb to let whether a simple, non-hardened, non- special ground part is available off the shelf govern you life.

I just made a leadscrew for a 54" bed 10K, though; and it is a little more involved than he notes

I chose to make a complete stub shaft that goes in the gearbox. This part was made out of 4140 prehard, and has the bearing journal, the threaded end for the nut, the step& shoulder for the gear location, the keyway, and the shoulder as the thrust surface on the outside of the gearbox all in one piece. It is also carefully bored on center 9/16" ID into the shoulder end (I made the shoulder longer than stock which interferes with nothing including the apron).

Then I took a length of rolled precision leadscrew (more than adequate for the task) from ROTON. Set up through the headstock in second op Hardinge, I manually turned parted it off, and turned and jounrnal on one end to fit the TS end bearing, and on the other a stub projection to go in the stub shaft already made. Then i used a heat gun on the OD of the stub shaft, inserted the end of the new screw, and shrunk them together. When it cooled, i put a small taper pin through for good measure.

You face 2 challenges. One, Roton has a minimum order of $80. So even if your leadscrew only costs ~$50 or $55 for your 4' bed, you still have to either buy something else or send them the balance anyway.

Next, a 3/4" OD leadscrew will not fit through the spindle of your 9" IIUC (someone may correct me here?) If it will, or if you have another lathe to use, be very careful setting up and centering. I used a 4 jaw chuck on both ends of my second op, for intance; and it took a while to dial in.

Oh, Yeah, your 3rd challenge out of the 2 I mentioned is to cut a slot in it for the rack drive geartrain. This can be done in steps on a horizontal or even vertical mill. I would surely use a slotting cutter (saw type) even if using a vertical. In my case I planed it. The screw, no matter who made it or where sourced, will take a nice pretty bow after the slot is milled. Part of the untold enjoyment of this immersion experience is to practice carefully straightening it to a good flat surface.

In summary, you are a wuss to be buying a leadscrew when you could be out in the shop spending untold countless hours of quality time & no small sum of $$$ for a cutter, leadscrew blank, and a stub shaft to make it. But I would not fault you for that decision, having enjoyed the experience for an extended period myself.

I have a perfectly good 4' leadscrew from my old bed, but not willing to part with it, yet, given my renewed appreciation for what it takes to fit a new one....

The 9" lathes have a 3/4 bore in the spindle, the leadscrew is 3/4 so it will go through the spindle, there should t be any problem in using the lathe its self to do the work, you could probably even cut the slot using a correctly ground tool and running the carrage back and fourth.

As to the ops trouble getting the gear box off, mine was on pretty good too, get a set of gunsmith screwdrivers, that was how I got mine off, they really grab in to the slot and don't want to slip out, let's you get the tork on the screw without fighting to keep the thing in the slot. You can special grind a screwdriver in to a gunsmith type screwdriver as well, which I've done on occasion.

robert102653 · May 4, 2015

ok well i got the three screws out of the gearbox and it is now soaking in the purple power (zep version). so that particular problem is solved. as to the lead screw well i think i will wait a bit and buy one after all because the problem with this one is about eight inches from the tail stock end and i don't plan to do anything that long at the moment. besides, as you say, something will turn up sooner or later. Since i am in the very beginning of restoration i have a ways to go. (no pun intended) ok that actually was intended. i would say my more immediate question is... if i hone out the headstock (and it definitely needs it),should i use one of those brake cylinders honing tools just till it is a bit smoother and take up the space created by removing the rather thick shims that are presently in the head stock shimming slot? (probably not the correct technical term) but i am talking about he slotted arms at each end of the headstock that have a Allen head bolt going down into them? n not sure it will work as i don't see that the inside bearing is split as well but that could just be the caked on grease and swarf. . by the way those shims are over .080 thick

stephen thomas · May 5, 2015

Here's a post in the rebuilding section about planing the 10K bed, and making a leadscrew for it.

http://www.practicalmachinist.com/v...n/10k-bed-low-rent-kingway-substitute-301575/

The section relating to the screw starts on this page:

http://www.practicalmachinist.com/v...ow-rent-kingway-substitute-301575/index2.html

smt

abarnsley · May 5, 2015

Well that is one way to slot a SB leadscrew.

When I converted my 4 1/2 ft bed Workshop 9in to B style, the leadscrew needed to be slotted.

Pulled leadscrew, drove to closest machine shop.

Machinist put leadscrew on T slot of mill table. Clamped it in a few places. 5/8 th T slot, will not let 3/4 screw fall in, and it is well supported full length.

Considering all the various parts involved, + - .005 anywhere on job (slot must be wide and deep enough) is fine..

Found center of leadscrew, and used a ~ 1/8th saw in an arbor to cut groove, moving clamps as he passed by.

Took about 20 minutes..

Playing with plain spindle bearing housing, without proper (Sunnon) hone machine is going to ruin it..

And If you take too much off, you crack housing adjusting bearing...

Even bad looking spindle and headstock are quite usable. It was built with state of the art ( cast Iron running on Steel) bearings from about 1900. Thus is handicapped to only running fairly slow RPM's, flinging spindle oil on you, and having primitive threaded spindle nose.. The Ford Model T of lathes...

There are better lathes out there to rebuild, use what you have....

kitno455 · May 5, 2015

Do not hone the headstock bearings.

allan

Vladymere gr · May 5, 2015

Robert102653,

I also don't think honing the headstock is a good idea. Can you post photos of your spindle and headstock bearings? Chances are they are not as bad as you think.

Vlad

swatkins · May 5, 2015

I'm pretty sure this guy can make you one if he does not have them in stock...

robert102653 · May 10, 2015

thanks i appreciate it.

robert102653 · May 11, 2015

I am still looking for a lead screw for a 1947 south bend model 9A lathe with a four foot bed. so for nothing has turned up on ebay and none of the makers of south bend parts responds to any emails either.

i am starting to pain all the parts i do have so i still have time but i am kinda anxious to get the parts too. i need a back gear also.

robert102653 · May 22, 2015

Thank you all for your advice but due to the fickle nature of the universe i have decided to quit this project and i have melted down the entire lathe and all its parts.... lol just kidding everything is proceeding apace i got the new lead screw and headstock casting every part is now stripped and painted that should be and i am fitting and putting everything together. I got a new tool post and made my first t nut for the compound. Again thanks to everyone i will be posting pictures soon.

swatkins · May 23, 2015

Where did you source your lead screw?

SBLatheman · May 23, 2015

swatkins said:
Where did you source your lead screw?

I supplied him with a leadscrew. I have used and new leadscrews for several sizes of South Bend lathes.
Ted
[email protected]

swatkins · May 23, 2015

SBLatheman said:
I supplied him with a leadscrew. I have used and new leadscrews for several sizes of South Bend lathes.
Ted
[email protected]

Do you happen to have any bearings for a Heavy 10 cross slide, large dial, 1950's era?

robert102653 · May 23, 2015

[email protected] you are the best

thank for supplying the lead screw it was perfect.
rob

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