Blade Exchange And Adjustment - SunStar SC 7900-Series User Manual

11) BLADE EXCHANGE AND ADJUSTMENT

Check the OFF-status condition of a power switch before adjusting.
Warning
(1) Knife (upper) pressure
When the needle bar is at the lowest point and the
knife(upper)ⓐ is the very left, the presser foot is attached to
the needle plate and the knife(upper)ⓐ is near the lower
bladeⓑ.
The standard clearance between the knife holder guideⓓ
and the knife holder shaft support barⓒ is 1mm.
Tighten the knife holder guide clamp screwⓔ after adjusting
the knife holder guideⓓ by loosening the knife holder guide
clamp screwⓔ.
Tip) The spring pressure is increasing when lifting the knife holder guide
ⓓ. The spring pressure is decreasing when descending the knife
holder guide.
Set the blade(upper)ⓐ and lower bladeⓑ to be aligned not to make the blade(upper)ⓐ
attached to the presser foot.. Then tighten the blade holder guide clamp screwⓔ.
Caution
(2) Knife removal
① Remove the knife(upper)ⓐ by loosening the knife holder
guide clamp screwⓔ and the knife clamp screwⓕ.
② Remove the lower bladeⓑ by loosening the lower blade
holder clamp screwⓖ.
(3) Knife reinstallation
① Fix the replacement lower bladeⓑ with the lower blade
holder clamp screwⓖ and fix the knife(upper)ⓐ with
the knife holder screwⓕ . (Refer to the "6-11)
OVERLAP WIDTH ADJUSTMENT OF UPPER
SEWING MACHINE")
② Adjust the knife holder guideⓓ referring to the above
knife(upper) pressure.
ⓑ
align front sides of knives
ⓒ
ⓔ
ⓓ
1mm
ⓐ
ⓕ
ⓑ
ⓐ
[ Figure 71 ]
[ Figure 72 ]
ⓖ
[ Figure 73 ]
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