In article , DoN. Nichols says...

One thing to watch for in the SB machines is whether it is a
model 'A', 'B', or 'C'. Model 'A' has the full power feed (longitudinal
and cross) with a quick-change gearbox. Model 'C' has only threading
with the "basket of gears" change system, where you tear down one
geartrain and build up another. (This tends to discourage setting the
right feeds for turning, simply because of the inconvenience.) The
model 'B' I think has the power cross-feed and longitudinal, but not the
quick-change gearbox. (Or is it the reverse?)

You were correct DoN.

A = quick change, and lever-selectable X- and L- feeds.

B = no QC, but still has feeds.

C = no QC, no feed worm in the carriage, so any longitudinal feed is
via the halfnuts.

Jim


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