Machine type
Factory heads that mount in a table with their own motor underneath: JUKI's DDL-5550 and DDL-8700 and the Singer 191D. They sew a straight lockstitch at several thousand stitches a minute and oil themselves from a pan. You're buying a rig, so check the table, oil pan, knee lifter and pedal linkage are there, and read the motor plate, because some need 220V or 3-phase power. Clutch motors hum whenever they're on, and servo motors are quiet. Plan on collection or freight.
3 models we cover.
Singer
Industrial$600–$950 typical ask
6 on eBay
JUKI
Industrial$1,075–$1,375 typical ask
35 on eBay

JUKI
Industrial$1,025–$1,600 typical ask
40 on eBay