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

Tim9

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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.IMG_2972.JPG 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. IMG_2974.JPG
And here's a pic of the silver soldered hard brazed repaired latch arm. IMG_2975.JPG
 
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.IMG_2980.JPG
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.

IMG_2983.JPG
 
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Countershaft selection gears were binding on the shaft do a quick polish and test of gear cleared this up quickly. 2A447D1F-59D8-47F6-8FF6-A2C0F82F5F35.jpegADB2A646-B953-4B55-93EE-47F9CDA1091E.jpeg
 
Replaced felts in gearbox oil passages and made new plugs
81DBB263-7FDC-4962-8DE4-DD65E8209854.jpeg2BF3CF5B-17E8-4A4E-9188-4502CD947DFF.jpeg1DB9A179-1C6E-4691-9A0B-ED2390FB66E1.jpeg.

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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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. 6485E241-8B0C-41AA-A121-A7561FB443A7.jpeg

97D96426-E33C-4116-973E-751AE86819A9.jpeg
 
5A4F26E1-5053-4D23-8AE8-25F215CF79D8.jpegh1FF75EB8-4AF2-4CE6-BD9D-3824ED032137.jpegAF3F7A03-2FA1-474F-88CA-494F97DC7804.jpeg0BBC2F0E-80F8-4A61-A358-520BC5FEFEA7.jpegNow 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.
 
Very cool! Brings back memories of when I did my 49 heavy 10L. I'm enjoying watching this, keep the pics coming.
 
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.
 
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. 6526E377-B72A-4BAD-A8BA-8C6641120822.jpegC24F683A-9A5A-4B0B-A9D2-1A9B38E242B7.jpeg98031DE4-2A5F-4879-9458-0EA81FB37C9C.jpegED7C43D1-AF2A-4A77-8AC2-661DADFD845F.jpeg58C7DB97-30C9-4D37-ACFC-AF0296269A0D.jpegC6C18DBE-45A8-47FE-8681-23E3DD3AC78A.jpegF5BA6EE9-5331-40C6-9552-D7BE7EADA148.jpeg11737DF4-56A6-4F12-9BBD-EF797939F660.jpeg

I do love working with Delrin
 
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