What's new
What's new

StanF South Bend 9A Rebuild Thread

Machine one out of a block of steel. I don't think grade of steel is important as it is going from cast iron to steel. A chunk of 1020 CRS would give you double the strength of that of cast iron. If you really want to make it strong, take a piece of 4145HT and make it out of that. The vise will wear out before it does.
 
You could also make it out of one solid round rather than welding two smaller rounds together or milling it out of a solid block. You want the hole for the cross bar to have some depth to spread out the leverage, but the 'T' shape doesn't really do anything but shave mass/weight off of it. If anything you could turn a step on the back side so the boss for the screw was the same, but the front end with the cross bar can stay round, and probably doesn't need to be as wide as the old cast one was.
 
Moving on to the very dirty Horizontal Drive Unit and motor...there are a couple of questions buried in here.
IMG_7326 (Small).jpg
Question 1...I've got a 1/2 HP Craftsman motor...ball bearing. I think I'm going to install it in place of the 79 year old GE motor. The GE motor still works, but I don't really trust the old insulation. Also, the old GE motor has sleeve bearings and oil fittings that are tough to access. I'd love to throw a TEFC motor on there, but I've already got the Craftsman. Any thoughts?

IMG_7328 (Small).jpg
The oil fittings seem to work okay, but I hate that they are 90 deg out:
IMG_7334 (Small).jpg
Common Craftsman motor...I picked it up off of Craigslist a few months ago - just as a spare.
IMG_7330 (Small).jpg

Question 2...this is the original SB pulley off the old GE motor. Interestingly, there is not a set screw. And the key is shaped different than most. How does the pulley stay on the shaft? I thought that the key might have a small taper to lock the pulley in place, but I haven't measured the key
yet.
I might drill and tap a set screw in the pulley. Comments?
IMG_7331 (Small).jpg
Disassembled...no brass bushings in this one - just cast iron. I did find some scoring on the shaft/bearings, but there's not any noticeable play. One of the felts was completely missing, and they evidently weren't kept oiled as well as the head stock. I'm going to run them as is, and keep them lubed properly. I'll bore it out and add brass bushings in the future, if necessary (doubtful!).
IMG_7343 (Small).jpg
Cleaned (no pictures - cleaning was tedious and no fun!) and 1st coat of paint:
IMG_7352 (Small).jpg
Blued all the hardware:
IMG_7355 (Small).jpg
I just realized that I should have cleaned and blued the motor pulley - I'll add that to the list for tomorrow.
 
Go with the Craftsman motor IMO.

Yes, that pulley is original. My lathe had the same pulley with the same tapered key. The old pulley on my lathe was so worn out, I replaced it with a cast iron pulley about double in size to get me a little faster
rpm's on the lathe. It's also set screwed to the motor shaft. The old GE motor on my lathe bit the dust twenty something years ago. The contacts on the centrifugal switch wore through to the metal! Replaced with a 1/2 HP DC PM motor. Been working great ever since. Like the variable speed, too!
Your doing a nice job of restoration there. Thanks for sharing.
 
Last edited:
the Bison chuck you selected. It could be just the pic angle, and I could certainly be wrong, but in the pics it appears to have a LOT of overhang from the lathe spindle.
Yes, I agree with you. It's not ideal. And it's massive compared to the original 5" Cushman chuck.

But, I won't be using it all the time. I've still got the old 5" 3 jaw chuck, a 6" 4 jaw chuck, a full 3c collet set and drawbar for small parts, and the larger Bison chuck. I've also got a faceplate, but doubt that I will use that very often.

So, lots of workholding options will be used - not just the larger chuck.

But when I need the Bison for its larger capacity, I will be very happy that I have it.
 
Machine one out of a block of steel. I don't think grade of steel is important as it is going from cast iron to steel. A chunk of 1020 CRS would give you double the strength of that of cast iron. If you really want to make it strong, take a piece of 4145HT and make it out of that. The vise will wear out before it does.
I sketched out a couple of things to discuss:

Two piece, welded:
The coped cut would be the most difficult operation. Otherwise, pretty easy operations.
Assem1 (Small).JPG

The final result looks pretty good. My welds will make it look uglier, for sure!
Assem1b (Small).JPG

If I start with a single block, then I think I end up with something like this. I can mill some chamfers to knock off the corners, etc, but it doesn't look as sleek as the two piece. Unless I'm not understanding your recommendation.

Part3 (Small).JPG
 
You don't need to machine a boss/sleeve on each end or for the piece the screw goes into., just leave it squared off.
I'd like to make it look more like an original piece - not an obvious replacement. Leaving it squared off is an option, but looking for other ideas too.
 
Some progress and a question:

Reversing Gear:
I found one minor problem...one of the 32 tooth reversing gears was a little chewed up.
IMG_7383 - Copy.jpg
I could file it smooth or buy a replacement gear on eBay, but I went ahead and bought a 10k reverse lever assembly. In the short term, it will be a donor for the 32 tooth gear. Then, in the future, I'll do the 10k lever upgrade.
s-l1600 (Small).png

One question...should I put a round felt in this short passage? The book is not clear on this older style of reverse lever.
(yes, I replaced the other round felt at the bottom of this passage)
IMG_7391 - Copy (Small).png

Horizontal Drive Unit:
It went back together without issue. The new serpentine belt adjusted nicely - just as expected.
IMG_7375 (Small).jpg
I'm using the Craftsman 1/2 hp motor, and ordered a new 2" pulley with a set screw. (Unfortunately, there wasn't enough meat in the old pulley to tap for a set screw). That's also a new V-belt.
I'll likely make some type of chip guard over the motor, since it has a few openings.
IMG_7388 (Small).jpg

Next on the "to do" list is the QC gearbox. I've already run into a couple of issues.
IMG_7385 (Small).jpg
One..I don't have a thin 7/8" end wrench to remove the leadscrew jam nuts...I ordered a thin wrench set from Amazon that will be here tomorrow.

Two...I already noticed some looseness/wear in the countershaft bushing. I'll investigate further after it's fully disassembled.
IMG_7386 (Small).jpg

ps: As a side note, I had a lathe once that did not have a QC gearbox, and it sucked. I will happily rebuild this one regardless of the issues!
 

Attachments

  • s-l1600 (Small).png
    s-l1600 (Small).png
    243.8 KB · Views: 0
I have a spare reversing gear assembly I picked up on eBay years back for a backup, too. Mine, the gears are getting loose and noisy! I'll probably get my son to print a couple of gears on his printer to replace them and quieten the gear train down a bit. As for the felt, your call, I know mine doesn't have the felt wick installed. I believe there is a felt wick on the shaft the stud gear goes on.
On the QCGB, I recall replacing all of the bronze bushings back when I rebuilt mine 45 years ago. We bought a badly used one from old man Sobal back then. I think there was a shaft I replaced, too.
It's looking nice! Keep the postings coming.
 
Stan, neither of my 2 SB9's have the felt wick on the old style reverse lever. I just fill it with oil. If you find that a felt wick is a good thing, please let us know so that I can install mine.
 
On the QCGB, I recall replacing all of the bronze bushings back when I rebuilt mine 45 years ago.
Since mine is a war production model, I don’t think it has any bushings. So I might have to set it up on the mill and bore the cast iron for bushings. I really hope that’s not necessary - it’s an odd shaped part that will be hard to fixture!

More to come, as I get it disassembled and inspected!

Ironically, this is one reason that I want to do the 10k reverse lever mod - to reduce wear on all the components. Switching to neutral will be quick and easy.
 
Last edited:
Another question...what's everyone's opinion of the reproduction nameplates on eBay? Mine is in pretty typical shape - it's worse than it appears in this photo.

I really don't think I have the patience or interest to repaint this one.

IMG_7398 (Small).jpg
A new one might match the fresh paint be more legible. I wish it was embossed and not just printed. I'd keep the old one in case I ever wanted to reinstall it.

Any thoughts?
s-l1600 (7) (Small).jpg
 
Some progress and a question:

Reversing Gear:
I found one minor problem...one of the 32 tooth reversing gears was a little chewed up.
View attachment 434795
I could file it smooth or buy a replacement gear on eBay, but I went ahead and bought a 10k reverse lever assembly. In the short term, it will be a donor for the 32 tooth gear. Then, in the future, I'll do the 10k lever upgrade.
View attachment 434797

One question...should I put a round felt in this short passage? The book is not clear on this older style of reverse lever.
(yes, I replaced the other round felt at the bottom of this passage)
View attachment 434798

Horizontal Drive Unit:
It went back together without issue. The new serpentine belt adjusted nicely - just as expected.
View attachment 434799
I'm using the Craftsman 1/2 hp motor, and ordered a new 2" pulley with a set screw. (Unfortunately, there wasn't enough meat in the old pulley to tap for a set screw). That's also a new V-belt.
I'll likely make some type of chip guard over the motor, since it has a few openings.
View attachment 434800

Next on the "to do" list is the QC gearbox. I've already run into a couple of issues.
View attachment 434801
One..I don't have a thin 7/8" end wrench to remove the leadscrew jam nuts...I ordered a thin wrench set from Amazon that will be here tomorrow.

Two...I already noticed some looseness/wear in the countershaft bushing. I'll investigate further after it's fully disassembled.
View attachment 434802

ps: As a side note, I had a lathe once that did not have a QC gearbox, and it sucked. I will happily rebuild this one regardless of the issues!

Aw, come on now... Or maybe for a bit more emphasis: "c'mon, maannn!" My Model "B" is not THAT bad to switch feed rates on.... The only reason I can say that is I don't HAVE a model "A"!! (Ha-Ha) Fantastic job on your rebuild. I'm pretty sure I have the tools/ability to do mine some day, but don't think I have the required patience do so. Mine still has the original laced-up LEATHER belt on it (the motor "V" belt may be original as well), she obviously has not had a lot of use over the last approx 80 years ("War production" plate on it). So she is still not looking TOO shabby at this point. However, I'm checking in now/then to follow your progress for some inspiration to possibly DO something with mine. Maybe at least a re-felt is in order! Very nicely done work on yours so far.
 
No pictures, but Amazon delivered the set of thin wrenches very early this morning. Disassembly was pretty quick. And I did take some video of the shaft wear. These two short videos show the wear in both ends of the same shaft in the QC gearbox:



Some options:
1) Do nothing - just reassemble it as is.
It will get worse over time and may be a little noisy.

2) Bore out the housing for brass bushings.
As I've thought more about this, I think it will be very difficult to get the new bores concentric with the old bores. Gear engagement might be too loose or too tight when I'm done. And getting both new bores concentric and aligned to each other may be tough - it will take two setups to get both ends bored out. And just holding the part on the mill will be challenging. Of course, if the housing isn't any good now, then why not go ahead and try it.

3) Buy a good, used one on eBay. (this will cost me almost as much as I paid for the entire lathe!)
I could install a later model one that came with brass bushings, and the 2nd oiler like shown below.
And I'd have some leftover gears/shafts/levers that I could keep as spares or sell to offset the cost.

s-l1600 (Small).png

4. Just give up and scrap the lathe, sell the parts and try to get some money back*

Any other thoughts?


* remember that today is April Fool's Day!
 
Last edited:
As for the bore the lead screw goes into. I'd leave it as is, mine is just as bad. I think some of the machining that looks bad is how SBL made this in their shop back in wartime. There are pictures out there showing a fixture setup on a special made machine made from a SBL. It drilled all of the holes in one operation, faced the bosses, too. I don't know if they even reamed any of the holes after the drilling operation.
 
As for sloppyness in the shafts, I've seen worse.
I would make a new shaft. Chances are the shaft has .002-.003" wear in it, that would tighten it up a little in the gear box.
I think you are getting too critical about trying to make this perfect. In wartime, this I'm sure was out of the question. If it was halfway decent, ship it! I consider your QCGB condition decent and should last another three generations IMO.
 








 
Back
Top