Singer 72W19 - Sharpening Knives of Picot Edge Cutting Attachment; Sharpening Lower Knife; Sharpening Upper Knife; Grinder Lubrication and Caution

INSTRUCTIONS FOR SHARPENING KNIVES
OF PICOT EDGE CUTTING ATTACHMENT 234734
When using Picot
Edge Cutting Attach
ment 234734, the best
results are obtained
when the knives are
sharpened on Knife
Grinder 234746.
H4 04 ^-4
Fig. 22. Knife GHnder 234746
The grinder should be set so that the top of the emery wheel
turns over toward the operator at about 3000 revolutions per
minute.
To Sharpen Lower Knife 234719, place it in position on the
two rear pins (K4, Fig. 22). Loosen the lock screw (H4, Fig. 22)
and move the knife carrier (J4, Fig. 22) until the left edge of the
blade is in line with the left edge of the grinding wheel. Then
move the lock screw (H4) to the right until it bears against the
casting and securely tighten the lock screw (H4). (The setting
of the lock screw (H4) is important, as it prevents the body of
the lower knife from being ground. After the lock screw has been
once properly set, it is not necessary to change its position when
sharpening either knife.) Turn the adjusting screw (F4, Fig. 22)
in
or out until the knife bears lightly against the grinding wheel.
Start the grinder and with the forefinger of the left hand pressing
lightly on the knife between the pins, sharpen the full length of
the cutting edge of the knife by moving the knife carrier (J4)
from side to side. The least possible amount ground off is usually
sufficient.
To Sharpen Upper Knife 234720, place it in position on the
two pins (G4, Fig. 22). Set the adjusting screw (F4) and sharpen
the blade as instructed above for the lower knife.
Caution: The knives should barely graze the emery wheel.
If the knives are held with too much ])ressure against the emery
wheel, the temper of the knives may be drawn until they are too
soft for use.
Lubrication: Oil should be regularly applied to the two ball
oilers (E4, Fig. 22).
From the library of: Superior Sewing Machine & Supply LLC