Replacing Tooth Holders on the Rotary Cutter Drum for the HM312 and HM315{0751, 6638} Caterpillar

Mulching Head:

HM312 (S/N: DJP1-UP)

HM315 (S/N: TXK1-UP)

Introduction

This special instruction outlines the basic procedures that are used for welding on replacement tooth holders on the rotary cutter drum.

Do not perform any of the procedures until you have read the information in this publication.

Also, refer to the appropriate Parts Manual, Operation and Maintenance Manual, and Service Manual.

Welding Requirements

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Personal injury or death can result from fumes, gases and ultraviolet rays from the weld arc. Welding can cause fumes, burn skin and produce ultraviolet rays. Keep your head out of the fumes. Use ventilation, exhaust at the arc, or both, to keep fumes and gases from your breathing area. Wear eye, ear and body protection before working. Protect yourself and others; read and understand this warning. Fumes and gases can be dangerous to your health. Ultraviolet rays from the weld arc can injure eyes and burn skin. Electric shock can cause death. Read and understand the manufacturer's instructions and your employer's safety practices. Do not touch live electrical parts. See "American National Standard Z49.1, Safety in Welding and Cutting" published by the American Welding Society. American Welding Society 2501 N.W. 7th Street Miami, Florida 33125 See "OSHA Safety and Health Standards, 29 CFR 1910", available from U.S. Department of Labor. U.S. Department of Labor Washington, D.C. 20210

Preparing the Metal for Welding

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Personal injury can result from flame cutting or welding on painted areas. The effect of gasses from burned paint is a hazard to the person doing the cutting or welding. Do not flame cut or weld on painted areas.

Cover all finished bores and threads. Finished bores and threads must be protected from all of the following items:foreign material, welding, gouging and paint spatters.

All grease, water, paint, rust, dirt and scale must be removed before welding. Any of these materials will discharge gas which will cause porosity in the weld deposit. Water and rust will cause hydrogen embrittlement. Hydrogen embrittlement causes cracks in the weld deposit.

Remove paint, rust, dirt, and scale with a wire brush or by buffing or grinding. Shot blasting all work areas will also remove foreign material.

Parameters for new Tooth Holder

1. Welding wire SG3

2. Welding current 270 AMP

3. Type of welding MAG Semipulsed

4. Number of welding layers 3

5. Minimum temperature of the material before welding 70 °C (158 °F)

Instruction for replacing the Tooth Holder

Illustration 1	g01171556

1. Take reference points of tooth holder (1).

2. If you need to take off the old tooth holder, use a cutting torch to remove the old tooth holder.

3. Position the new tooth holder on the rotor at the reference points.

4. Spot weld the new tooth holder.

5. Weld the short sides of the tooth holder. Weld the two longer sides of the tooth holder.

6. Repeat this procedure a total of 3 times in order to have 3 layers of weld.

   Note: After a tooth holder has been replaced the rotary cutter drum must be checked for balance.

Balance Information

1. Install the work tool on the host machine. Refer to the Operation and Maintenance Manual.

2. Raise the work tool in the transport position.

3. Set the engine speed to LOW IDLE.

4. Activate the high flow control on the host machine. Refer to the Operation and Maintenance Manual, "Operator Controls" of the host machine for additional information.

5. The rotary cutter will begin to rotate. Activate the continuous flow function on the host machine. Refer to the Operation and Maintenance Manual, "Operator Controls" of the host machine for additional information.

6. Continue to gradually increase the speed of the work tool.

7. Check the work tool for vibrations. If abnormal vibrations are felt stop the work tool.

8. If the work tool is not operating properly, the rotary cutter drum must be balanced.

   Note: Special tooling is required in order to balance the rotary cutter drum. Do not attempt to balance to the rotary cutter drum without the proper tooling. Contact your Caterpillar Dealer for balancing information.