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Piecing together 1943 SB 9C Workshop Lathe

J

jglowien

Plastic
Joined
Jan 27, 2015
Location
Red Hook
Bought a stripped down 1943 vintage 9C last January and since then have been buying bits and pieces to create a whole operating lathe. I bought this one (too) cheap on ebay and have over a grand now invested, buying a full set of change gears, horizontal drive, live centers, tool bits, electric motor, reversing switch, and the list goes on. I wanted one of these for quite a while for my occasional hobbyist needs, having run one in HS shop 50 years ago.

I'm getting very close now, but still need a pulley for the new electric motor. It's a new cap start 120v 1 phase motor (I know, I know ... everyone says to get a 220v 3 phase motor and VFD ... remember this is for occasional hobby use, not a production shop) has a 5/8" shaft with a 3/16" keyway. As a further clue how retro I am, I am also going to use the 1" wide flat belts as it originally had. I figure I would have to drop another $500 just to convert everything to modern v-belts.

Anyone know where I could procure the flat pulley for the motor? I'm guessing the belt surface would be somewhere between 1.5 - 2" in diameter, to step the 1730 rpm down by 5x- 6x on the horizontal drive shart. The large flat pulley on the horizontal drive is 10" dia.

I will now brace myself for the abuse coming ...
 
That lathe did not use a flat belt from the motor to the countershaft originally. It used a B section V belt, with a normal v belt pulley on the motor. The inner surface of the belt ran right on the flat countershaft pulley. It looks kinda crazy, but works fine.

allan
 
So it is the motor pulley that tries to keep the belt on the larger horizontal drive pulley? Seems crazy to me also. Also explains the market for v-belt conversions for the other belt drives on the lathe.

Was it a problem keeping the belt on the large pulley? Or am I worrying about it for nothing? If this is the 'right way' to configure the belt and pulley, how long should I expect the belt to NOT wander? Certainly makes finding a pulley a lot easier.
 
V belt will not wonder on the countershaft pulley. They stay in line perfectly well. Even if you don't have it tight enough and it does slip, it will not come off. But you will also find that the flat belt driving the lathe pulleys will slip before the V belt does. It is a strange but pretty neat solution for driving the countershaft.
 
You've convinced me. I did assume the motor and horizontal drive shafts would have to be parallel at least. How does a 'B' belt differ from 'BX'? And have you ever seen anyone use the post and mounting screw on the horizintal drive cast frame to attach a spring tensioner for the motor belt?
 
I've now got both a 2.15" & 2.65" O.D. pulley on order now. I wasn't sure what speed reduction was needed. Stay tuned.
 
The excitement is building ... I'm one flat belt away from finally putting this stripped down SB lathe back in service. After that initial investment of $202, I'm at $1,200 to date, so beware of 'inexpensive' machines on the web.
I really appreciate the advice that kitno455 gave me on how the v belt will stay on the large pulley.
Now another belt question: the flat belt with the wire splice vs. a glued one. Seems the advantage of the spliced one is its removeability, since you don't need to dissassemble both the horizontal drive and the headstock to mount the belt. Am I correct in assuming it is possible to open that splice?
On the downside might be more noise (clicking sound?) and a little slippage possibly.
A continuous belt on the other hand would be smoother, quieter, not as noisy. However if going that route, why not just use a molded serpentine belt of about 1" width?
I'm sure there is much wisdom on this forum to help me here.
 
I don't know about anyone else, but I love that click. If you have the countershaft way back, maybe 16" or so, and you loosen the tension, you can get it to go click, slap - very cool background music.

The little pins do come out, all too often when you don't want them to. If you find a piece of rawhide, or even a piece of baleen if you live near the shore, it'll stay in there after a few hours, and it'll run a little quieter too. Somebody makes a pin covered with plastic that works well.
 
Something like this: Gates 520J10 Belt

A "J" section belt is more flexible than what you might find at the auto store. J10 is about 0.97" wide. I've ordered from Biedler before, best price+shipping I could find. The first three numbers indicate the length.

paul
 
It still means taking both the horz drive and headstock apart to mount the J10 belt ... not sure it's worth it. I'll keep that option as plan B however.
 
Finally got the lathe base mounted on the rolling table that will be its home going forward. Next step is going to be mounting the horizontal drive unit with the new motor onto the table, which will determine the length of the flat belt between them. Problem is I need to remove the belt tensioning lever to straighten its pivot pin. Got bent before I bought it. However the chuck is in the way and needs to be removed. Any wisdom on loosening the chuck from the spindle?
 
The first thing to do is to soak the daylights out of it with Liquid Wrench, or similar, for at least 24 hours. Some say 48 hours. Then you have to decide what part of the headstock you can easiest replace. My first effort is always a good strap wrench around the cone pulley, and another strap wrench around the chuck. I can replace a plunger on the bull gear fairly easy.

Don't hammer anything. Keep soaking and using better leverage as you move toward risking more expensive parts. By the way, give yourself an extra couple mils of end play before doing any of this; about every tenth time, that's all it takes.
 
That's kind of what I figured. My most urgent concern was how to immobilize the shaft. The chuck is big enough to generate enough leverage with a strap or even a pin wrench around it. I was hesitant to try putting a strap around the cone pulley for just the 'shear pin' reason you offered. So I'm off to buy a 55-gallon drum of WD-40 ....

and the chuck thread is indeed right hand?
 
It is right hand. That's what happens when people leave the chuck on for years. Every small shock tightens it a little bit more. I take mine off between projects, that is, when the lathe is gonna sit for a day or three. BTW, before taking it off, put something on the ways underneath the chuck. Different chucks come off at different points, and you can ding the ways pretty fast if it catches you off-guard. My Grizzly catalogue works perfectly for this.
 
I was already looking around for a nice thick sheet of polyprop foam to protect the ways. My guess is the chuck weighs between 15-25 lbs. The previous owner of the lathe apparently was a gunsmith, so lord knows the last time the chuck was unmounted.
Given the success I had about ten years ago loosening the crankshaft nut on my '85 BMW 635Csi, my strategy is slow and easy. Lots of penetrating oil and a long lever.
 
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