SOUTH BEND 9C GEAR CHANGE PROBLEM

[358scott]

I have a 9c and want to cut 5/8 24 threads. I haven't changed gears before, so I pulled off the gears that were being used before I purchased it and cleaned all the gears. When assembling the gears (stud gear 16, an 80 and 48) I noticed that the lower gears align, but they don't align with the stud gear. I can see (photo #2) that the previous owner ran it this way (witness marks on the gear behind the stud gear). What is the solution to this problem? Shim the two lower gears or face the gear behind the stud gear.
Scott

 

[SLK001]

The gear with all the dimples in this picture doesn't appear to be a South Bend gear. It is causing all your problems. Take it off and trim most (if not all) of the radius off the face. Then, your problems will disappear.

 

[358scott]

This is a photo of a SB 9c forward-reverse gear from the internet. It looks the same as mine. So it has to be a south bend gear.

 

[SLK001]

This is a photo of a SB 9c forward-reverse gear from the internet. It looks the same as mine. So it has to be a south bend gear.

Okay, then you're going to have to move around some washers (or spacers). Your 80 tooth gear is already at full extension on its stud. Either a spacer is in the wrong place, or something is wrong with your setup. The 42 is ALSO at full extension (meaning there is no extra room for spacers) on its stud. Are both of these mounting studs properly installed on the banjo? They have a rectangular shape on the end, which runs in a rectangular groove on the back of the banjo. If they aren't correct, a lot of space on the stud will be gone, thus necessitating the need to remove some spacers.

Oh, and take a wire brush to your rusty gears - then oil them so that they soak up the oil.

 

[358scott]

This is the way I received it and someone before me ran it with the gears misaligned. I added a spacer behind the 80 and 48 to align them for now until I can figure out what is wrong (I'll use thin nylocks to hold them).
Thanks
Scott

 

[jcp]

The only other thing I can think of is the headstock is to far to the left. They are only clamped to the bed and need to be aligned to the banjo so the gears line up.

 

[SLK001]

The only other thing I can think of is the headstock is to far to the left. They are only clamped to the bed and need to be aligned to the banjo so the gears line up.

Usually, SB lathes have a pin in the bed that mates with a hole in the headstock casting, so there is no chance for misalignment. I know that the 10L and larger lathes have this pin. I don't know if the 9" has the pin or not. If it doesn't, then moving the head forward about 1/4" will solve the alignment issue. I don't have a 9" parts manual to look for a pin.

This could be an easy-peasy quick fix.

 

[jcp]

My 9A has no such pin.

 

[358scott]

So I can move the headstock to the right? Or can I move the banjo to the left?

 

[jcp]

Try moving the headstock to the right.....you may or may not have a locating pin for headstock to bed alignment.