21533,
18" x 8',
"O" series Catalog No. 71-E,
QCG lathe,
The gearbox plate says pat# 810634 Jan 23,1906,
and has the South Bend logo as well.
There are only 8 gearbox cone gears (All I have seen have 9.)
The gearing combinations allow from 2 to 112 tpi.