NPK M20C, Instruction Manual, Page: 82 / 152

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JAW INSPECTION AND MAINTENANCE
TEETH REPLACEMENT
The M20G/M28G/M38G Material Processors have three types of jaw teeth (mp1, mp2,
and mp8). All three types can be cut off and replaced when worn beyond rebuild
ability.
Following is the procedure for teeth replacement:
1. Remove worn teeth by carbon arc (t12) or acetylene cutting torch (t13).
2. Prepare surface for new teeth.
3. Place new teeth into proper location.
4. Heat dry welding rod to 300°F+ (150°C+) .
5. Pre-heat weld area to 300°F - 400°F (150°C - 200°C) .
6. For joining, stringer beads are best. For build-up, weaving is acceptable. Use one
of the following rods (or wire equivalent) or equal: Airco Austex 361, Cronatron
7770, Eutectic 3205, Hobart Smooth Arc MC, McKay Chrome-mang, Stoody 2110.
7. Hard face rod for tooth and structure wear surfaces. Pre-heat as in Step number 5.
Use two passes maximum for hard facing. Use one of the following rods (or wire
equivalent) or equal: Airco Hardcraft CR-70, Cronatron 7350, Eutectic Eutectrode
N70, Hobart Smooth Arc 16, McKay Hardalloy 40 Tic, Stoody 19, 21, or 77.
8. Adjust weld current to rod manufacturer’s specification.
9. Peen each layer.
10. Cool slowly. Cover weld in cold environments.