SINGER 251 - Manual (Page 3)

Machines of Class 251 produce top quality, straight-line, single-needle, lock stitching in fabrics as fine as
ladies' lingerie or as heavy as mens' overcoating.
DESCRIPTION
General Features
Federal Stitch Type #301.
High Speed (see chart on page 4). Maximum speed
dependent upon nature of work and ability of
operator.
Gear driven, lubricated. Rotary Sewing Hook on
horizontal axis makes two revolutions for each stitch.
Upper gears are spiral-bevel. Lower gears are
hypoid-bevel.
Hook Shaft mounted .160 inch forward of vertical
axis of Needle Bar for improved stitch formation.
Drop Feed guided by mounted journal bearings to
prevent side movement of Feed Dog.
Length of stitch determined by a Push-Button Stitch
Regulator on top of machine arm. Regulator includes
Locking Device to prevent changing of stitch length
during machine operation: (For maximum possible
.stitch length, see chart on page 4). Stitch Length Indi­
cations on Machine Pulley are in view of operator.
Automatic Lubricating System (see X-Ray View on
opposite page). Centrifugal Pump delivers oil under
pressure from Reservoir to all principal bearings. Oil
wicks lubricate bearing surfaces in head end of ma­
chine and return excess oil to Reservoir. Oil Guard
covers entire path of Take-up Lever.
Oil Flow Window, in direct view of operator, reveals
circulation of oil inside machine arm.
Machine Dimensions: Bed length 18-3/4 inches,
width 7 inches. Space at right of Needle 1 1 inches.
Machine Head is supported by Machine Base and
Oil Reservoir, designed to fit the cutout in table.
Machine Pulley 147016. Outside diameter of belt
groove 2.90 inches for 3/8 inch V-belt. Effective diam­
eter for 5/16 inch round leather belt is 2-3/8 inches.
When the machine is in operation, the top of the
machine pulley must always turn over toward the
operator.
Knee Lifter, regularly furnished, is an integral part
of the Machine Base and Reservoir.