South Bend lathe drive ?

[TIMAR]

Have 9x36 south bend lathe that I purchased several years ago but never did set up. Figured out how everything mounts up but not sure how to tension the belt. Can't get it tight enough. I have looked at several catalogs from the 1930's and don't see this drive set up anywhere. Anyone here have any ideas or have a manual for this one?
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[TimV]

Timar: hard to tell from the angle of your picture, but is that a V belt? My SB has a flat leather belt, and I've never had slipping problems, but it's run from below, not above like yours. A V belt, especially a thin one, might not have enough contact area to keep it from slipping.

 

[TIMAR]

It is a flat belt. Trying to get another pic uploaded

 

[TIMAR]

Here's another angle
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[TimV]

Hmm--looks pretty straightforward and close to "normal" other than being on top, but, no, I haven't seen one like that before. What's the sign of the belt not being tight enough--slippage, coming off, or something else? I'm linking a page that I had bookmarked from a while ago that's belt-related--maybe it will give you some ideas. Lots of guys replace the leather belts with serpentine auto belts.
SB belts

 

[TIMAR]

Slipping, and it's a new belt

 

[J. Schwiebert]

Can you raise the jackshaft by adding a few washers to increase the distance between the spindle and the jackshaft?

 

[TimV]

Don't have much to offer other than the obvious, then--making sure you're not locked in multiple gears, making sure everything turns freely without the belt engaged (if memory serves they're a bit stiff to turn over by hand but it should certainly turn--if not, you've got other problems that need to be addressed first--I assume you know the drill on lubing the lathe?) and the possibility the leather has been treated with wax or other preservative that may need to burn off before it grips well.

 

[Janicholson]

Under the motor there is a flat cast plate. the rear of which is pivoted. The front edge has a lever (maybe 2 levers) that tension the belt. They are to be let off (loosened) when not using the lathe to prevent stretching the leather belt. If the adjustment of those levers, is maxed out, the belt has stretched and needs to be shortened, or replaced. Grizzly Company purchased South Bend, and may have the belt. To get the belt on requires much effort to take apart the 3 pulley drive spindle. Or the existing belt can be Skived and shortened while on the machine. (a thin fat tapered splice) Look it up on Youtube. Pretty easy but do not substitute the correct glue. A serpentine belt of the length will work but does require the disassembly. Jim

 

[JD Seller]

Looking at your flat belt. It looks thin for what your doing. I have several flat belt driven machines. They usually use at least a 1/4 to 5/16 thick and then full width of the pulleys. Then you do not leave the leather belt tight when not in use. Just flip it off either the top or bottom pulleys.

 

[M-MAN]

Belt drive machines require double layer leather belts. Then you have to neetsfoot oil the leather. They make cloth/rubber power belts that work well and they are very thick also. There is a pivot tension you haven't found yet.

 

[TIMAR]

Thanks for all the replies. Thinking the new belt may be too long. It came with the machine. Still would like to see this motor setup in a catalog tho because even the 2 tensioning levers are a bit confusing