HQ Infinity Service Manual
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4. Tighten the two adjusting screws, alternating between the two, until the needle is centered side to
side in the needle plate hole.
NOTE
: When you tighten the right side adjusting screw, the needle moves to the right. When you
tighten the left side adjusting screw the needle moves to the left.
5.
Carefully tighten the three bulkhead bolts until snug.
6.
Check that the needle is still centered in the needle plate hole.
7. If the needle position has changed, loosen the adjusting screw on the opposite side of where the
needle needs to go and tighten the adjusting screw on the side where the needle needs to go. Then
tighten the other adjusting screw.
8.
With both the adjusting screws tightened and the needle centered side to side in the needle plate
hole, fully tighten the three bolts into the bulkhead.
9.
Check to insure the needle is still centered side to side in the needle plate hole.
15. Timing
Loop Lift and Hook-to-Needle Distance Timing
Loop lift
is a universal hook and timing term for all lock- stitch sewing machines. When the needle lifts a
specified distance from the bottom dead center (BDC), the hook point is set to coincide with the needle.
Loop lift is the radial position of the hook to the needle, commonly referred to as
timing
.
Another part of timing is
hook-to-needle distance
, or the axial distance from the hook point to the
needle scarf. Loop lift is the radial setting of the hook and hook-to-needle distance is the axial setting
of the hook. Both of these adjustments are set on the hook and fixed with the same screws. Since two
things are being done at the same time, this can be a little difficult until practiced. Timing is not difficult.
However, it does require precision. For good and dependable results each time, timing must be set
accurately and consistently each time.
The third part of timing is
needle bar height
. This ensures that the loop of thread above the needle eye
by the needle scarf is at the correct height so the hook can enter the loop. If the hook collides with the
thread on the loop, shredding occurs. If the hook misses the loop, skipping occurs. Needle bar height will
be discussed in the next section.
NOTE
: If loop lift is not set correctly then needle bar height will appear wrong. This has fooled
many a technician. If needle bar height is too far off, it will not be possible to set needle distance
into the scarf because the scarf will not be aligned with the hook. Needle bar height will only be
wrong if some one changes it or sets it wrong in 99.9% of cases.