3 Needle bar rise
3.0. General hints:
The term "needle bar rise" denotes the amount
of
needle rise that is required to form
a loop
of
the proper size. This amount is measured in millimeters or inches from the
lowest point
of
the needle stroke with the needle bar drive rotating in its normal
direction.
When the needle bar has risen the required distance from the bottom
of
its stroke,
the hook point should be opposite the centerline
of
the needle.
The amount
of
needle bar rise required to form the loop is depended on the size and
quality
of
the thread used, the needle size, the type
of
sewing hook, the sewing
speed as well as other factors. The needle bar rise
of
the
Pfaff
141
normally is 1.6
mm, or
0.062 inch. For further particulars, please refer to a needle rise table or the
instructions for mechanics.
Model A and B machines:
Model
C machines:
Model D machines:
3 .1.
Set feed regulator on "0".
1.6 mm or 0.062 inch.
2.0 mm or 0.078 inch.
2.2 mm to 2.4 mm or
0.086 to 0.094 inch.
3.2. Setting the amount
of
needle bar rise with the aid
of
a gauge:
3 .2.1.
Tum
the balance wheel until the needle bar is at the lowest point
of
its stroke.
3 .2.2. Slip the clamp
of
the needle rise gauge onto the needle bar above the needle holder.
3.2.3. Slip the gauge (for the amount
of
needle rise specified) onto the needle bar above
the clamp and push clamp and gauge up until the gauge bears against the lower
needle bar bushing and the balance wheel can be turned neither forward nor
backward.
3.2.4. Pull out the gauge.
3 .2.5
Tum
the balance wheel in its normal direction
of
rotation until the clamp strikes the
bottom
of
the lower needle bar bushing.
3.2.6 When the needle bar has risen to this position, the loop has reached its proper size
and the hook point should be exactly opposite the centerline
of
the needle. The
hook should be set close to the needle (for a rough setting
of
the lateral clearance
between hook and needle: for further particulars, see Par. 5 below).
3.2.7. Prerequisite for adjustment the amount
of
needle rise is that both the needle bar and
hook drive mechanisms have no excessive play and work smoothly.
3
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