Jaw Inspection And Maintenance; Jaw Inspection: S, C, And G Jaws; Weekly Inspection; Jaw Profiles: S, C, And G Jaws - NPK M20S Instruction Manual

JAW INSPECTION AND MAINTENANCE

JAW INSPECTION: S, C, and G JAWS

WEEKLY INSPECTION

With new S, C, or G jaw sets, the teeth will contact before the cylinders reach full
stroke. As the teeth continue to wear, the cylinders will reach full stroke and a gap will
be apparent between the opposing jaws. If wear continues to this point or beyond, the
crushing efficiency may decrease and the full cylinder force will be transferred to the
cylinder end cap (c5) and retaining cap screws (OO).
This situation should be avoided. The jaws or teeth should be inspected and
maintained to avoid this gap.

JAW PROFILES: S, C, AND G JAWS

S, C, and G JAWS: Profiles can be checked against NPK original profile templates.
Call the NPK Service Department for assistance at 1-800-225-4379.
S JAWS: These jaws are hard-faced. The best time to rebuild them is as soon as the
hard face pattern is worn off. If the hard face pattern is gone and wear is in to the jaws
itself, the profile should be rebuilt to that of the template. Do not allow tip wear to
exceed .75" (19 mm) compared to the template or the cylinder will bottom out.

JAW BUILD-UP AND HARDFACING (M38S, M28S, and M20S)

For build-up and hard facing of jaw, use the NPK template to check jaws so that they
are to the original profile. Contact NPK for the correct templates, drawing no. M3803-
9501 and M3803-9502 (M38S), M2803-9500 and M2803-9501 (M28S), and M2003-
9500 and M2003-9501 (M20S). Then, refer to JAW and TOOTH REBUILD
PROCEDURE.
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