# Clean and repair South Bend 9" lathe Model A with 4-1/2' bed.



## Tim9 (Sep 18, 2018)

This thread will be my documenting of a recent lathe I purchased. I have a 3-1/2' SB 9" Model C which I converted to a model B. It's a good working lathe but does have a few issues. And since I have a Clausing 12" Model 5903 with 24" centers, I decided I would rather spend my efforts on tweaking and repairing a 36" center SB than putting all that effort into another 24" between center SB. FWIW, The Clausing also is on the list of needing repairs but its in storage for now.
   Anyway, I located a 4-1/2" SB A in Houston so I drove there and back in one day to get the lathe. I paid @450 for the lathe and it was just a basic lathe that had been dropped. The QCGB had a broken arm latch. It was very, very ratty. But, it was a 4-1/2' bed and the bed was in better shape than my SB-C with 24" between centers.
	

		
			
		

		
	



	

		
			
		

		
	
  Here's a pic of the bed once I cleaned it up. 
  And here's a pic of the Quick Change Gearbox Broken latch arm casting. It's a clean break and being cast iron, nothing is bent. Just broken. 
	

		
			
		

		
	



 And here's a pic of the silver soldered hard brazed repaired latch arm.


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## Tim9 (Sep 18, 2018)

The QCGB is just really messed up. Its been packed with a heavy grease. And the grease is all gummed up and loaded with debris. It has worn bushings. I can't even begin to shift between gears. I disassembled it and it's soaking in mineral spirits.
	

		
			
		

		
	



  I replaced a few worn bushings and unclogged all of the oil passages in the QCGB. Had to drill through a few of the lead plugs for access to the passages.


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## woodtickgreg (Sep 18, 2018)

Subscribed! I'll enjoy watching this one.


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## Tim9 (Sep 19, 2018)

Countershaft selection gears were binding on the shaft do a quick polish and test of gear cleared this up quickly.


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## Tim9 (Sep 19, 2018)

Replaced felts in gearbox oil passages and made new plugs




	

		
			
		

		
	
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for the drilled access holes. Actually, in the pic of the one plug you can see I just dropped some solder on the drilled hole through the original lead plug. Replaced shaft felts also and reassembled QCGB.


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## Tim9 (Sep 20, 2018)

Next program I ran into was a broken tooth on the headstock countershaft bull gear. After thorough cleaning of gear I brazed the affected area with some bronze filling the gap between the remaining adjoining teeth where the missing tooth was located. Then quick set up to clean up the bronze to bring diameter in line with remaining teeth on gear.


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## Tim9 (Sep 20, 2018)

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Now it was time to cut some new teeth on the brazed bull gear. I set up the gear in the mill using a rotary table along with the correct involute cutter.


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## woodtickgreg (Sep 20, 2018)

Very cool! Brings back memories of when I did my 49 heavy 10L. I'm enjoying watching this, keep the pics coming.


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## Tim9 (Sep 20, 2018)

woodtickgreg said:


> Very cool! Brings back memories of when I did my 49 heavy 10L. I'm enjoying watching this, keep the pics coming.


Thanks Greg. I do like the simplicity of the SB 9" lathe. I'm a little familiar since I have a 3-1/2' SB also. In any case, this 4-1/2' Model A has a good bed without too much wear and abuse plus the initial inspection tells me that the headstock and spindle are in good shape. Although it appears to have crashed... Then pulled out of service... And then dropped.., Its got good enough bones for my use. The QCGB had a good bit of wear in the bronze bushings and all the passages were clogged. Someone used a grease gun on it. Anyway, it's all good after replacing the bronze bushings and cleaning up the shafts. 
   I also noticed a couple of more broken teeth on some gears. The 80 tooth gear has 2 bad spots and one of the reverse tumbler gears has a broken tooth. I'm going to make a delrin reverse tumble gear and braze the 80t gear. I'm thinking the delrin reverse tumbler will cut down some of the drivetrain gear noise. That said, all of this stuff is fairly easy and inexpensive to repair on my end.


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## Tim9 (Sep 20, 2018)

This really went quick. I had spent a lot of time adding the indexing plates to my Palmgren rotary table. It works and I’ve used it to repair the bull gears on both of my SB lathes. 
  That said, it’s not a super fast process counting turns and rotating the rotary table when on its side. There’s a lot of friction when the table is on its side. 
    So, I have since made an Arduino spindexer as shown in the two below links. 





http://liming.org/millindex/
I used it to make my delrin gear. The original gear is about 3/4” thick so I made an arbor for the gear and cut a gear about 2” thick. I’ll cut this in half and then face both ends to match the original gear. That way I’ll have a gear for both of my lathes and I’m thinking it’ll cut down on gear train noise. 
	

		
			
		

		
	











I do love working with Delrin


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## Tim9 (Sep 21, 2018)

Here I milled new teeth of the repaired brazed 80t gear. The Arduino stepper worked flawlessly. Really cool item to build IMO.


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## Tim9 (Sep 22, 2018)

So, it’s time to mount and somewhat level the lathe.  Since it’s going on a wooden bench of heavy old actual 2 by 12’s for the top with 4x4 legs... I wanted a steel base to mount on top of the bench. 
  I welded 2 x 2 x1/4” angle iron to 2 x 2 square tube with 1/4” wall.


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## Tim9 (Sep 22, 2018)

Since the lathe was assembled on the bench and it’s now too heavy for me to lift up to slide the newly welded base, I used a couple of machinery jacks to lift the lathe about 2-1/2 above the bench top. I then slid the angle iron steel base underneath the lathe.


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## Tim9 (Sep 22, 2018)

Oh yea, I forgot about mentioning the broken cast iron tailshaft leg. I’m just tapped out financially at this point plus I didn’t want to wait another week for a leg I ordered off EBay. So I cut a piece of 6 x6 x 1/4 steel tube to length matching the height of the leg. I then used nickel 55 rod to weld this to the cracked cast iron.


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## Tim9 (Sep 22, 2018)

First pic is the tailshaft side. Second pic is headstock side. Third pic tailshaft again. Sorry for the confusion but I just take pics as I finish a project and they seldom are in chronological order. 
Here’s the lathe finally mounted to the bench. The headstock is shimmed to the 1/2” Steel plate which is tacked to the angle iron base. There are two 3/8 x 16 studs threaded into steel 1/2” plate. Lathe is shimmed and headstock tightened down. Tailshaft end has two sliding plates which are welded to 6x6 tube which tightens to the angle iron base once leveled. It appears to be somewhat functional. The test will be after I use the lathe a while.
   But I’m happy with the outcome so far.


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## Tim9 (Sep 22, 2018)

I needed to fire up this puppy to at least see condition of headstock / spindle. That said I really just rigged the countershaft and motor. I received this lathe with the motor shown. It’s a 1 hp Dayton motor which has a singing front bearing. It's also way too big. The capacitors hit against the table. So I have to raise it up with wood shims. It's sitting about 1-1/2 inches higher than the table base in order to allow space for the capacitors. I'll deal with a more permanent solution at some later date. I just want to get it running for now. 
       I disassembled it and removed the bearing, cleaned the bearing, and oiled it up. I also needed the part number of the bearing to get the replacement bearing.
   In the past I’d run to American bearing supply to get the proper replacement bearing but the last few times I went there they really raped me on price.
  I don’t mind paying retail for a bearing but they were charging me 20.00 for some crap bearing made in Turkey. That’s more than retail price for Timken or SKF BEARINGS !
   It’s a shame because I’ve been going to this same business since 1982 when I had my Auto shop.
   After the second  raping, and on the attempted 3rd rape on price... I told the counter man to keep his bearings and now I just order all bearings on-line.
   Anyway, since the motor had a shielded bearing , it was an easy temp repair to clean, lube and order 10 sealed permanently lubed SKF bearings from Amazon for the same price ABS would have charged me for one crap 6203 made in some third world country.


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## Tim9 (Sep 22, 2018)

I fired the lathe up and noticed a repetitive binding noise in the gear train. The motor would also strain on every full revolution of the gear train. And if the belt was loose the belt would stop and continue slipping.
  After close inspection I could see the stud gear at the reverse tumbler was out of round and looked like a bent shaft. I removed the reverse tumblers and removed the stud shaft and mounted it in my other lathe to check it. It wasn’t bent.
   I then cleaned and closely inspected the 20t stud gear. That’s when I noticed it had been brazed and repaired at some point.
It was obviously out of round.


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## Tim9 (Sep 22, 2018)

Time to make another delrin gear.  
	

		
			
		

		
	






No point showing everyone my making another gear. But here are four pics of a bushing I had to make for my keyway broach.
  I have two broach kits. One is the midget set for 1/4” to 1/2” shafts 
The othe kit is 1/2” up to 1-1/4 shafts.
   Wouldn’t you know it. Neither kit had a 9/16” keyway broach bushing. So the quickest fix was making a bushing to fit over the 1/2” bushing.
   That’s what’s shown above. I’m kind of proud and surprised I pulled off turning that bushing since the wall of the thin section is 25 thousands by 3/4 Long.
   I have to thank Joe Pieczynski for his videos. He has a great video on cutting thin wall bushings. He pulls off some stuff way more impressive than 25 thousandth brass wall.... but it’s his technique which showed me how to do it. Without his videos, I’m sure I’d have crashed this bushing.
   The second to last pic is the brass bushing sitting on the 1/2 broach bushing. You can see where I sawed the opening in the brass bushing. I used a jewelry saw to saw this thin walled bushing. Last pic is my using the drill press to broach the delrin gear.


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## woodtickgreg (Sep 23, 2018)

Fun watching your progress!


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## Tim9 (Sep 23, 2018)

Neither of my lathes  came with thread dials. I purchased one of those 3-D printed gauges off eBay. They are pure crap. The gear self destructed after a few weeks. 
  Anyway it’s time to make a real thread dial. I’m using the printed dial as a model to roughly copy.


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## Tim9 (Sep 23, 2018)

Here I’m using a slitting saw to cut the dial marks.


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## Tim9 (Sep 23, 2018)

And here is mostly finish dial with 32t gear. 
	

		
			
		

		
	




Tomorrow I’ll clean up the paint on the dial face with some scotch-brite and a file.


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## Tim9 (Sep 23, 2018)

woodtickgreg said:


> Fun watching your progress!


Thanks for the encouragement Greg !


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## Tim9 (Sep 26, 2018)

Cleaned up the thread dial and mounted. Works good but I’ll probably do my next dial for other lathe a little different.


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## Tim9 (Sep 26, 2018)

On to getting a little 4’ chuck set up for the lathe. Picked this up on eBay for 38.00 and it’s pretty tight with tight & ground jaws. Pleasantly surprised with this chuck but it came without a backing plate. That said, the lathe I purchased came with a backing plate but no chuck. That’s because the previous owner couldn’t unscrew it and it’s probably why the bull gear had a broken tooth. With a little heat I got The backing plate off. But it has a 4 bolt pattern and my chuck is 3 bolt pattern.
  In the second pic you can see the 3 transfer studs screwed into the “new” chuck.
  Third pic shows where I filled one of the 4 bolts with a stud and silver brazed it to fill that hole since I wasn’t comfortable where the new hole would be so close to another hole.
  Last pic is cleaned up backing plate after fitting it’s boss to specs of new chuck.


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## Tim9 (Sep 26, 2018)

Here’s the completed chuck mounted. You can see close up of a chipped / damaged threads. The backing plate would not screw on either spindle and would bind @ 1/2 way trying to install backing plate on spindle. I cleaned up the threads by setting lathe to 8tpi and engaged half-nuts and rotated lathe manually.... then adjusted the threading tool to engage threads. I did this by moving crosslide into position while also adjusting the threading bar tool at the QCTP Allen mounting screws until the lathe was in sync with the threads. Once everything was in sync I tightened Allen screws and then would just move cross slide a thousandth and manually rotate lathe to clean the threads. Anyway I hope that makes sense. It worked and backing plate freely screws onto the spindle.


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## Tim9 (Sep 27, 2018)

I’m going to make an alignment test collar bar next in order to test for twist and I’ll design it to double as a tailshaft line up bar. Not much design to this other than setting the inner most collar out away from headstock enough to take a cut and then the rear collar will also have a couple inches of shaft for another cut. When used as tailshaft line up bar.... the shaft will be on dead centers. And since the bar is done on the cheap and made of aluminum, I’m going to loctite a hardened steel cap on the tailshaft side before I Center drill it for the MT-2 dead center adapter. I could do same for the headstock side but I like the aluminum on this side as I don’t need a dogbone or faceplate to lock the shaft since the dead center is rotating with the spindle and it produces enough friction to lock the shaft in place for the light cuts I’ll be taking for these tests.
Well... On to plan B. I need to make a lathe dog and I'm going to put steel caps on both ends. FWIW, I don't have a lot of steel rounds yet have an abundance of aluminum. That's why I am using an aluminum bar.


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## Tim9 (Oct 2, 2018)

Here’s a pic of test collar bar end piece where’s I loctited a hardened end cap for the tailshaft end. I then mounted two 2” pieces of bar stock about 6” from each other. First cut was horrendous. Chatter and horrible finish on the outer end towards the tailshaft.


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## woodtickgreg (Oct 2, 2018)

Interesting.........


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## Tim9 (Oct 2, 2018)

So... even though I had already leveled the bed and bench I went back to square one. I first checked the spindle for its shims in the headstock. I felt the housing and it was warm. When I rotated the spindle it was somewhat tight at a certain point while spinning by hand. When I received this lathe both headstock bolts were loose. I properly shimmed the headstock. Buying the steel assortment of shims from McMaster was a very good move.
    I then checked the lineup of tailshaft to spindle by placing Mt3 dead center in spindle and a Mt2 in tailshaft.  They were a good bit off. Both low by a mile and to the rear.
    Sorry I  don’t have many pics of this but it’s all basic stuff really.
   I took my tailshaft out of other lathes tailshaft and mounted that in a 3-jaw which was mounted to spindle. Then moved this lathe’s tailshaft flush to shaft in chuck. I miced the difference in height.... about .020  
     WOWSERS !
Anyway I made shims and placed them between tailshaft and tailshaft base plate.
   Checked again and it occurred to me that even though I had already leveled this lathe I should check it again. The lathe is in a room of raised house. The 100 y/o house is pier type construction with wood flooring. 
  Low and behold, it was way way out of level. And significant bed twist.
So I loosened bolts and reshimed headstock. Moved level to tailshaft end and it was now good.


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## Tim9 (Oct 2, 2018)

Got it set so that there is no twist now. It’s perfect from front to back with only a slight amount of lean headstock to tailshaft end. 
    Took a few cuts and had to adjust tailshaft screws to get it just right but after a few tries I’m now within a thou. 
   I figure this is good enough since things will most likely change again due to the way it’s set up in a raised house on a wooden bench.


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## woodtickgreg (Oct 2, 2018)

I need one of those levels!


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## Tim9 (Oct 2, 2018)

Well, I think I’m about finished this project. I don’t plan on painting it especially since I don’t have the free time. In addition im not concerned how it looks. As long as it’s fully functional and accurate I’m golden.


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## Tim9 (Oct 2, 2018)

woodtickgreg said:


> I need one of those levels!


Yeah Greg, I think the a precision level is a real lifesaver when dealing with a lathe. It's just hard to tune it in with a bed-twist.
  I was really surprised how much twist I had. Mind you, I had leveled this lathe. And it's set on that 1/4" angle iron / square tube base. And that's sitting on a pretty heavy wooden bench with 2" thick top and 4x4 legs/frame. 
   Even with all that, the bed had twisted a good bit.

In any case, I'd be going nuts trying to figure this out if I did not have a good machinist level. 

It'll be nice once I get a better workshop with a concrete slab.


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