SB 14 vs 14 "precision" parts

[thedarkknightt]

Is the lead screw different between these two lathes of the same length and vintage?

I went to look at two this week, and they are the same vintage and length, but the precision lathe has a lead screw that's chewed up pretty good just down from the headstock. Both are 8ft. The precision also has the turret.

 

[benmychree]

"Precision" could mean toolroom tolerances, which generally are half of the tolerances of an ordinary "engine" lathe, The book "Testing Machine Tools by Schlesinger gives tolerances for alignment and accuracy for most all types of machine tools of both ranges of accuracy of toolroom and ordinary shop machinery.

 

[JBTEK]

In the old South Bend catalogs, the heavy lathes were generally available in both standard engine lathe versions and in tool room versions. As John mentions above, the tool room versions were made to tighter tolerances than the standard versions (and also included the taper attachment and perhaps other options) and accordingly carried a higher price. The lead screw is one part that gets tighter tolerance for the tool room version. I have always guessed that the lead screws were otherwise interchangeable but I have no personal experience to confirm that.

Perhaps you can find the South Bend catalog for the year of your lathe (or close to it) on the Vintage Machinery site, and that might shed some light.

 

[Beckerkumm]

I'd take whichever is in better condition as to bed , ways, gears, etc. A lead screw can be replaced more easily than a worn bed, cross slide, or mashed headstock gears. Neither leadscrew is likely very precision any more. Dave

 

[thedarkknightt]

I'm thinking about these.
Thanks guys- I'm still about in the middle of a 13"x7' restoration.
I really need to finish one at a time, but if opportunity knocks...

I guess when you get more than one lathe thats over 1500 pounds, it becomes a bit harder to convince the wife they are hobby toys.