I clearly need to replace some gears on my lathe, the question is how
many? There are four gears showing signs of wear, one of them really
bad. Replacing all four gets pretty expensive. The lathe is a 14 1/2"
Southbend.

First, naming the gears. Here's a picture of the group:
http://users.frii.com/sos/Steve/Overall.jpg

Parts Works names them as follows:
top gear in picture (this gear is on the spindle): "cone-pinion"
two gears just below cone-pinion: "twin gears"
gear which right twin gear drives (below R twin gear): "reverse gear"

Here is a top close up view of the cone-pinion:
http://users.frii.com/sos/Steve/Cone_Pinion.JPG

A close up view of the two twin gears:
http://users.frii.com/sos/Steve/Twin_Twin.jpg
The one on the right is clearly on its last legs.

A close up view of the right twin gear and the reverse gear beneath it:
http://users.frii.com/sos/Steve/Twin_Reverse.jpg
Again, the wear on the right twin gear is pretty serious.

I definitely need to replace the right twin gear. The cone-pinion
doesn't look so good, I don't know how to tell on the other two. I will
appreciate any recommendations and discussion .

Thanks,
Steve