NPK M20C, Instruction Manual, Page: 87 / 152

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87
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JAW INSPECTION AND MAINTENANCE
HARDFACING: K JAWS
If hard facing is to be performed, the jaw must be preheated to 300° - 400°F (150° -
200°C) before hard facing is applied. Failure to preheat the tip area will cause the hard
facing to crack and chip off prematurely. Using a suitable hard face rod, apply the
material in stringer beads vertically on the front and sides of the piercing tip and
parallel to the moveable jaw on the lower face of the piercing tip. This pattern will allow
for the most efficient piercing and the least amount of interference. Peen after each
pass and maintain inner pass temperature.
DO NOT APPLY MORE THAN TWO (2)
LAYERS OF HARDFACE MATERIAL!
After hard facing is completed, grind the
piercing tip to the desired profile. Do not pierce with the tip until the tip area
temperature has normalized. This process takes approximately twelve hours. It is
recommended that the tip area is covered with a heat blanket, covered with dry sand,
floor dry, or other suitable material. Refer to the “HARDFACE” section and use the
same procedure.