Adjusting The Rotary Hook Lubrication Amount - Brother T-8420B Instruction Manual

9. ADJUSTING THE ROTARY HOOK LUBRICATION AMOUNT

9. ADJUSTING THE ROTARY HOOK LUBRICATION
AMOUNT
Be careful not to touch your fingers or the lubrication amount check sheet against moving parts such as the rotary
hook or the feed mechanism when checking the amount of oil supplied to the rotary hook, otherwise injury may
result.
Use the following procedure to check the amount of oil being supplied to the rotary hook when replacing the rotary hook or
when changing the sewing speed.
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More oil Less oil
Too much
33
Spattered oil
Correct Too little
T-8420B, 8450B, 8720B, 8750B
CAUTION
<Guide to lubrication adjustment>
1. Tilt back the machine head.
2. Turn the oil adjusting screw (1) to adjust the height to
within 9-14 mm.
<Checking the lubrication amount>
1. Turn off the power switch.
2. Remove the thread from all points from the thread take-up
to the needle.
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3. Remove the needle and the bobbin.
4. Use the lifting lever to lift the presser foot.
5. Turn on the power switch.
6. Run the machine at the normal sewing speed for
approximately 1 minute without sewing any material
(following the same start/stop pattern as when actually
sewing).
7. Place the lubrication amount check sheet (2) to the left of
the rotary hook (the right side is the right side of the rotary
hook), and hold it in place while running the sewing
machine at the normal sewing speed for approximately 8
seconds. (Any type of paper can be used as the
lubrication amount check sheet (2).)
8. Check the amount of oil which has spattered onto the
sheet.
<Adjusting the lubrication amount>
1. Tilt back the machine head.
2. Turn the adjusting screw (1) to adjust the lubrication
amount.
・ If the rotary hook adjusting screw (1) is turned
counterclockwise, the lubrication amount becomes
greater.
・ If the rotary hook adjusting screw (1) is turned
clockwise, the lubrication amount becomes smaller.
3. Check the lubrication amount again according to the
procedure given in "Checking the lubrication amount"
above.
* Turn the adjusting screw (1) and check the lubrication
amount repeatedly until the lubrication amount is
correct.
4. Check the lubrication amount again after the sewing
machine has been used for approximately two hours.
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