Singer 491D Owners Manual

The Singer 491D arrived as a genuine industrial workhorse rather than a home-sewing machine — a high-speed, single-needle lockstitch built for production environments, released to the trade with its own dedicated 1973 service and parts manual covering two distinct variants: the 491D200GA and 491D300GA. One owner's own review sums up the core distinction plainly: the two model numbers "had to do with the max height of the needle bar," giving shops a choice between standard and taller-clearance configurations depending on the materials being sewn.

The two variants also diverged in their feed hardware — the 300GA version ran a 21-tooth feed dog (22 teeth per inch) in place of the 200GA's standard unit, alongside a different tension spring and dedicated large-needle-hole and small-needle-hole throat plates suited to heavier material work. Both machines shared the same rotating-hook mechanism with an oil flow regulating thumb screw for lubrication control, a feed reverse lever for reinforcement stitching, and a 135x7 #14 needle system standard across the range — genuinely serviceable, field-repairable hardware built for shops that couldn't afford downtime.

The factory manual itself covers the full range of adjustments a working machine needs over its service life: setting check spring height and tension, positioning the needle bar at the correct height, timing the sewing hook and setting it sidewise in relation to the needle, timing the feed mechanism, and setting the feed dog at the correct height. It also walks through removal and replacement of principal assemblies — the sewing hook, arm shaft, and needle bar among them — plus oil filter replacement, the kind of preventive maintenance that kept industrial machines like this running reliably shift after shift.

This factory service manual covers the procedures, adjustments, and parts diagrams needed to keep a Singer 491D200GA/300GA running the way it was built to.