Brother rh-918a Sewing Machine User Manual


 
9. STANDARD ADJUSTMENTS
RH-981A
62
9-11. Adjusting the contact between the knife and the hammer
1. Remove the hammer. (Refer to the previous page.)
2. If the knife incision on the surface of the hammer is
very deep, if there are two or more incisions on the
hammer because different knives were used, or if
only part of the incision has been made, grind the
surface of the hammer smoothly until a single knife
incision can still be seen faintly.
3. The cutting pressure over the whole of the hammer
should be uniform so that the material will be cut
cleanly.
Grind the surface of the hammer so that the knife
incision will be uniform over the whole of the
hammer.
* The hammer can be filed until its height is 19 mm.
4. If the material cannot be cut cleanly even though
the hammer has been ground correctly, check
whether the tip of the knife is worn.
* If the tip is worn, replace the knife.
Do not use the old hammer after the knife has
been replaced, otherwise it may damage the tip
of the knife.
Adjusting the contact between the knife and the hammer
To see the knife incision more easily, color the cutting surface of the hammer with a marker pen.
1. Operate the hammer three times with the knife making a mark on it each time.
2. Adjust the position of the hammer or contact between the knife and the hammer until the knife consistently makes
a mark in the same place.
Filing the cutting surface of the hammer
Use a flat file for filing.
1. Filing the cutting surface of the hammer on which the knife incision breaks off or is shifted
1-1.Grip the hammer in a vise.
1-2. File the surface of the hammer smoothly until the knife incision is erased away.
2. Filing the cutting surface of the hammer in which knife incision is deep
2-1. Grip the hammer in a vise.
2-2. File the surface of the hammer smoothly until a single knife incision can still be seen faintly.
0971Q
3090Q
1. Knife incision
is correct
2. Knife incision
is too dee
p
3. Two knife
incisions
4. Partial knife
incision