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Curious Gasket On SB9a Underdrive Cabinet Model

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Skowinski

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Continuing to work on restoring this old South Bend lathe I picked up a couple of months ago. Finally have the cabinet stripped and repainted, and almost done with cleaning, stripping and repainting the various parts of the lathe itself. I'm about to mount the bed with it's legs back on the cabinet in preparation for putting it all back together and came across this gasket #51 in the parts catalog (pic below). It's described as "195x3 VEL. GASKET" in the key for the diagram.

There isn't one there now. Not clear where this is supposed to go, presumably between the leg and cabinet, but that seems it would make the bed and ways unlevel as it would raise the headstock side. Anyone know the function of this gasket and exactly where it goes? On the inside of where the leg sits on the cabinet, to stop oil from running off onto the undermount drive and motor?

edit: this is the underdrive cabinet model

 
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BaronJ

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Hi Skowinski,

I believe you are right, that it would go between the top of the cabinet and the lathe foot. I doubt that it will make any real difference to the bed level.
Check the heights of parts 4 and 9. You will have to assemble part 9 first though, using parts 10 and 6. See if there is a hight difference.
 

benmychree

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The way it is drawn, it looks like it goes between the spacer pedestal and the bed, but does the drive belt go through the two holes in the spacer pedestal? That does not make sense ---
 

dlane

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Is it a underdrive or rear drive ?
 

benmychree

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With the angular cutouts in the bed under the headstock, I thought it would be a underdrive; maybe the gasket was only used on rear drive models.
 

Skowinski

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Sorry guys, to clarify it's the cabinet model and underdrive mounted motor, inside the cabinet.

Don't think it can go between the bed and leg as the belt does run through those openings. Those surfaces look to be machined to fit together with not gasket, like the leg on the tailstock side.

I'll measure the height of the two legs, as suggested by BaronJ, and see if they are the same, or if the headstock side leg is shorter by the thickness the gasket should be (whatever that is...).
 

dlane

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The gasket could be for a back drive unit, did you remove it during tare down, or never had one
 

Skowinski

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Didn't have a gasket as it came to me. But, this lathe has been owned by a hillbilly judging from some of the "repairs" I've found, so I've had to use photos and the parts catalog to be certain I'm putting it back to original condition.

I didn't copy enough of the page to show, but that headstock side leg is indicated as specifically for the underdrive mount, so the gasket is specific for that model. A gasket like that isn't shown for the regular back drive bed leg as far as I can tell.
 

tq60

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Just guessing but your thought about below headstock against pan seem best to keep drippings out of drive.

Sent from my SAMSUNG-SM-G930A using Tapatalk
 

Skowinski

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I measured the height of the headstock and tailstock side legs. They are within a millimeter of each other, in fact, the headstock side leg is slightly taller if anything. Putting the gasket between the bottom of the leg and cabinet, or between the top of the leg and bed would increase this difference.

I think I'll put a thick gasket around the opening in the top of the cabinet that the drive belt passes through, just enough to block any oil that wants to run off into the opening, but not wide enough the be between the leg and cabinet. Either that, or a very thin gasket between the leg and cabinet...
 

derf

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That gasket doesn't seal anything....it's for vibration dampening. It keeps the chip pan from rattling.
 

BaronJ

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Hi Guys,

Is it one of those heavy self adhesive tar things, like the damping pads used inside vehicle door panels then ?
 

Skowinski

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That gasket doesn't seal anything....it's for vibration dampening. It keeps the chip pan from rattling.
Ok, not for sealing then....vibration damping, I guess that makes sense. Anyone know what this gasket was made of, so I might try to find a modern substitute? I assume it's impossible to buy these OEM now.

edit: if for vibration reduction it would presumably need to go between the headstock side leg and the cabinet?
 
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francist

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I am curious as to material as well. I've been trying to think of what they would have abbreviated to "vel." -- and about the only thing I come up with is "vellum". Would that make any sense at all? Essentially a paper-thin barrier against chips and oils, although I think vellum is a bit more durable than regular paper.

Atlas machines had what they referred to as "fibre" washers and gaskets which were quite thin. I've used a modern impregnated fiber gasket material as a substitute and it seems to work ok. It's only about 0.025" thick. Wonder if it was something similar for the SB gasket in question?

-frank
 

derf

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We're talking 1940's technology......it's just a paper gasket about .040-.050" thick, much like you would find on a '57 Chevy water pump. I replaced the ones on mine with 1/8" neoprene rubber. It made a big difference in noise. It goes between the leg and the chip pan or cabinet.
 
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