Hercules 4-1/2" - 6" 13A Trigger Grip Angle Grinder

Unpacking and Initial Checks

When unpacking, ensure the product is intact and undamaged. If any parts are missing or broken, call 1-888-866-5797 as soon as possible. Reference 57348.

Important Safety Information

General Power Tool Safety Warnings

WARNING: Read all safety warnings and instructions. Failure to follow warnings and instructions may result in electric shock, fire, and/or serious injury. Save all warnings and instructions for future reference.

Work Area Safety

• Keep the work area clean and well lit. Cluttered or dark areas invite accidents.
• Do not operate power tools in explosive atmospheres (e.g., near flammable liquids, gases, or dust). Power tools create sparks that may ignite dust or fumes.
• Keep children and bystanders away while operating a power tool. Distractions can cause loss of control.

Electrical Safety

• Ensure power tool plugs match the outlet. Never modify the plug. Do not use adapter plugs with grounded power tools.
• Avoid body contact with grounded surfaces (e.g., pipes, radiators, ranges, refrigerators).
• Do not expose power tools to rain or wet conditions.
• Do not abuse the cord. Keep it away from heat, oil, sharp edges, or moving parts.
• When operating outdoors, use an extension cord suitable for outdoor use.
• If operating in a damp location is unavoidable, use a Ground Fault Circuit Interrupter (GFCI) protected supply.

Personal Safety

• Stay alert, watch what you are doing, and use common sense. Do not use while tired or under the influence of drugs, alcohol, or medication.
• Use safety equipment. Always wear eye protection. Use dust masks, non-skid safety shoes, hard hats, or hearing protection as appropriate.
• Prevent unintentional starting. Ensure the switch/trigger is in the off-position before connecting to power or battery, or when carrying the tool.
• Remove any adjusting key or wrench before turning the power tool on.
• Do not overreach. Maintain proper footing and balance.
• Dress properly. Do not wear loose clothing or jewelry. Keep hair, clothing, and gloves away from moving parts.
• If dust extraction and collection facilities are provided, ensure they are connected and used properly.
• Only use safety equipment approved by an appropriate standards agency (e.g., ANSI-approved eye protection, NIOSH-approved breathing protection).

Power Tool Use and Care

• Do not force the power tool; use the correct tool for the application.
• Do not use the tool if the trigger does not turn it on and off.
• Disconnect the plug from the power source before making adjustments, changing accessories, or storing the tool.
• Store idle power tools out of reach of children and untrained persons.
• Maintain power tools. Check for misalignment, binding, or breakage. Have damaged tools repaired before use.
• Keep cutting tools sharp and clean.
• Use the power tool, accessories, and bits according to instructions, considering working conditions.

Service

Have your power tool serviced by a qualified repair person using only identical replacement parts.

Safety Warnings Common for Grinding, Sanding, Wire Brushing, or Abrasive Cutting-off Operations

• This power tool is intended for use as a grinder, sander, wire brush, or cut-off tool. Read all safety warnings and instructions.
• Do not use accessories not specifically designed and recommended by the manufacturer.
• The rated speed of the accessory must be at least equal to the maximum speed marked on the power tool.
• Accessory diameter and thickness must be within the tool's capacity.
• Ensure the accessory's arbor size properly fits the spindle.
• Do not use damaged accessories. Inspect wheels for chips/cracks, backing pads for cracks/wear, and wire brushes for loose wires before each use. Run the tool at maximum speed for one minute with a new accessory to check for breakage.
• Wear personal protective equipment (face shield, safety goggles/glasses, dust mask, hearing protectors, gloves, apron).
• Keep bystanders a safe distance from the work area.
• Hold the power tool by insulated gripping surfaces only when performing operations where the accessory may contact hidden wiring or its own cord.
• Position the cord clear of the spinning accessory.
• Never lay the power tool down until the accessory has come to a complete stop.
• Do not run the power tool while carrying it at your side.
• Regularly clean the tool's air vents.
• Do not operate near flammable materials.
• Do not use accessories that require liquid coolants.
• Maintain labels and nameplates. Contact Harbor Freight Tools for replacements if unreadable or missing.
• Avoid unintentional starting. Prepare to begin work before turning on the tool.
• Do not depress the spindle lock during starting or operation.
• Do not leave the tool unattended when plugged in. Turn off and unplug before leaving.
• Secure and support the workpiece using clamps or other practical means.
• This product is not a toy. Keep out of reach of children.
• People with pacemakers should consult their physician before use and follow specific precautions.
• Understand that common sense and caution are factors that must be supplied by the operator.

Kickback and Related Warnings

Kickback is a sudden reaction to a pinched or snagged rotating wheel, backing pad, brush, or accessory. It causes the tool to be forced in the opposite direction of the accessory's rotation. Avoid kickback by taking proper precautions:

• Maintain a firm grip and position your body to resist kickback forces. Always use the auxiliary handle.
• Never place your hand near the rotating accessory.
• Do not position your body in the area where the tool will move if kickback occurs.
• Use special care when working corners, sharp edges, etc. Avoid bouncing and snagging.
• Do not attach saw chain woodcarving blades or toothed saw blades, as they create frequent kickback.

Safety Warnings Specific for Grinding and Abrasive Cutting-off Operations

• Use only recommended wheel types and the specific guard designed for the selected wheel.
• Ensure the guard is securely attached and positioned for maximum safety.
• Use wheels only for recommended applications (e.g., do not grind with the side of a cut-off wheel).
• Use undamaged wheel flanges of the correct size and shape.
• Do not use worn-down wheels from larger power tools.
• Dress appropriately. Wear leather leggings and fire-resistant footwear. Avoid clothing that can catch sparks or molten metal.

Safety Warnings Specific for Abrasive Cutting-off Operations

• Do not "jam" the cut-off wheel or apply excessive pressure.
• Do not position your body in line with and behind the rotating wheel.
• When the wheel binds or you interrupt a cut, switch off the tool and hold it motionless until the wheel stops. Investigate and correct the cause of binding.
• Do not restart the cutting operation in the workpiece without letting the wheel reach full speed.
• Support panels or oversized workpieces to minimize wheel pinching and kickback.
• Use extra caution when making "pocket cuts" into walls or blind areas, as the protruding wheel may cut utilities or objects causing kickback.

Safety Warnings Specific for Sanding Operations

Do not use excessively oversized sanding disc paper. Follow manufacturer recommendations. Oversized paper presents a laceration hazard and may cause snagging or kickback.

Safety Warnings Specific for Wire Brushing Operations

• Be aware that wire bristles can be thrown, even during ordinary operation. Do not overstress wires.
• If a guard is recommended, ensure the wire wheel or brush does not interfere with it.

Vibration Safety

This tool vibrates during use. Prolonged exposure may cause physical injury. To reduce risk:

• Seek medical advice if you experience symptoms like tingling, numbness, or white/blue fingers.
• Do not smoke during use.
• Wear suitable gloves.
• Use tools with the lowest vibration when possible.
• Include vibration-free periods in your workday.
• Grip the tool lightly, letting the tool do the work.
• Maintain the tool as explained in this manual. Stop use if abnormal vibration occurs.

Grounding

WARNING: TO PREVENT ELECTRIC SHOCK AND DEATH FROM INCORRECT GROUNDING:

Consult a qualified electrician if unsure about outlet grounding. Do not modify the power cord plug. Never remove the grounding prong. Have damaged cords or plugs repaired by a service facility before use. Have a proper outlet installed by a qualified electrician if the plug does not fit.

Grounded Tools: Tools with Three Prong Plugs

Tools marked "Grounding Required" have a three-wire cord and three-prong grounding plug. The plug must connect to a properly grounded outlet. Grounding provides a low-resistance path to carry electricity away from the user, reducing shock risk. The grounding prong is connected via the green wire inside the cord to the tool's grounding system. This green wire must be the only wire connected to the grounding system and must never be attached to an electrically "live" terminal. The tool must be plugged into an appropriate, properly installed, and grounded outlet.

Double Insulated Tools: Tools with Two Prong Plugs

Tools marked "Double Insulated" do not require grounding. They have a special double insulation system that satisfies OSHA requirements and complies with applicable standards. Double insulated tools can be used in either of the 120-volt outlets shown.

Extension Cords

• Grounded tools require a three-wire extension cord. Double Insulated tools can use a two or three-wire cord.
• Use a heavier gauge extension cord as the distance from the supply outlet increases to prevent voltage drop, loss of power, and tool damage. The smaller the gauge number, the greater the cord's capacity.
• When using multiple extension cords, ensure each cord meets the minimum wire size requirement.
• When using one cord for multiple tools, add the nameplate amperes and use the sum to determine the minimum cord size.
• Ensure outdoor extension cords are marked with "W-A" (or "W" in Canada).
• Ensure the extension cord is properly wired and in good electrical condition. Replace or repair damaged cords.
• Protect extension cords from sharp objects, excessive heat, and damp or wet areas.

TABLE A: RECOMMENDED MINIMUM WIRE GAUGE FOR EXTENSION CORDS (120/240 VOLT)

*Based on limiting the line voltage drop to five volts at 150% of the rated amperes.

Symbology

Warning Symbols and Definitions

A: Safety alert symbol. Used to alert to potential personal injury hazards. Obey all safety messages following this symbol to avoid injury or death.

DANGER: Indicates a hazardous situation which, if not avoided, will result in death or serious injury.

WARNING: Indicates a hazardous situation which, if not avoided, could result in death or serious injury.

CAUTION: Indicates a hazardous situation which, if not avoided, could result in minor or moderate injury.

NOTICE: Addresses practices not related to personal injury.

Specifications

Functional Description

The angle grinder features:

1. Side Handle
2. Spindle Lock
3. Trigger
4. Trigger Lock
5. Wheel Guard
6. Wheel Guard Bolt
7. Wheel Guard Lock Lever
8. Grinding Wheel (sold separately)

Diagram showing the angle grinder with numbered parts.

Operation

Read the ENTIRE IMPORTANT SAFETY INFORMATION section before setup or use.

Tool Set Up

WARNING: TO PREVENT SERIOUS INJURY FROM ACCIDENTAL OPERATION: Ensure the Trigger is in the OFF position and unplug the tool before performing any setup procedures.

Adjusting the Wheel Guard

WARNING: TO PREVENT SERIOUS INJURY: Do not operate without the Wheel Guard properly installed.

1. Pull out the Wheel Guard Lock Lever.
2. Rotate the Wheel Guard to shield you during work.
3. Push the Wheel Guard Lock Lever back into place to secure it.
4. Check that the Wheel Guard is firmly in place before proceeding.

Installing Auxiliary Side Handle

WARNING: TO PREVENT SERIOUS INJURY: Do not operate with one hand only or without the Side Handle properly installed.

1. The Side Handle can be installed in one of two positions, on either side of the Gear Housing.
2. Screw the threaded end of the Side Handle clockwise into the selected position. Tighten securely.

Diagram showing side handle installation options.

Installing a Non-threaded Grinding Wheel or Cut-Off Wheel

Requirements for Grinding Wheel:

• Rated to at least 10,000/min
• No larger than 6" diameter
• 7/8" round arbor hole
• 0.035" to 0.3" thick
• Suitable for surface grinding, not edge grinding
• Dry and clean
• Proven undamaged by inspection

Requirements for Cut-Off Wheel:

• Rated to at least 10,000/min
• No larger than 6" diameter
• 7/8" round arbor hole
• 0.035" to 0.3" thick
• Suitable for edge grinding, not surface grinding
• Dry and clean
• Proven undamaged by visual inspection

WARNING! TO PREVENT SERIOUS INJURY: When using a Cut-Off Wheel, a wheel guard designed specifically for Cut-Off Wheels must be installed if the wheel fails.

WARNING! TO PREVENT SERIOUS INJURY: Use only 4.5" grinding wheels with 4.5" guards. Use only 5" grinding wheels with 5" guards. Use only 6" grinding wheels with 6" guards.

1. Press and hold the Spindle Lock to prevent the Spindle from turning.
2. Remove the Flange Nut. Keep the Flange in position on the Spindle.
3. Thread the Flange Nut onto the Spindle. Wrench tighten only enough so the wheel is securely held.

WARNING! TO PREVENT SERIOUS INJURY: Do not overtighten Flange Nut. Overtightening can damage the wheel, causing failure.

Diagram showing assembly of grinding wheel with flanges and nut.

Installing a Threaded Accessory

CAUTION TO PREVENT INJURY: Wear heavy-duty work gloves when handling wire wheels and brushes. These accessories are sharp. Do not exceed maximum rated speed. Do not use a damaged brush; replace immediately as damaged wires can cause injury.

Accessory Requirements:

• Rated to at least 10,000/min
• No larger than 6" diameter
• Threaded opening of 5/8" x 11 TPI
• Undamaged
• A sanding disc and backing pad, a sanding flap disc, a wire wheel, or a wire cup brush

1. Press and hold the Spindle Lock Button to prevent the Spindle from turning.
2. Remove the Flange Nut and the Flange.
3. Thread the accessory firmly onto the Spindle. Wrench tighten.

WARNING! TO PREVENT SERIOUS INJURY: Use only 4.5" grinding wheels with 4.5" guards. Use only 5" grinding wheels with 5" guards. Use only 6" grinding wheels with 6" guards.

Workpiece and Work Area Set Up

1. Designate a clean, well-lit work area, free from distractions.
2. Route the power cord safely to avoid tripping hazards or damage. Ensure enough slack for free movement.
3. Secure loose workpieces using a vise or clamps.
4. Ensure no hazardous objects (e.g., utility lines) are nearby.
5. Use personal safety equipment: ANSI-approved eye and hearing protection, heavy-duty work gloves.
6. Provide for sparks and debris that will fly off the work surface.

General Operation

WARNING: TO PREVENT SERIOUS INJURY: Grip the tool firmly in both hands.

1. Ensure the Trigger is not locked on, then plug in the tool.
2. To start: Push Lever forward and squeeze Trigger. To stop: Release Trigger. For continuous operation: Push Lever forward, squeeze Trigger, then depress Trigger Lock. To turn off continuous operation: Squeeze Trigger to release Trigger Lock, then release Trigger.
3. Allow the tool to reach full speed before touching the work material.
4. Grinding/Sanding: Apply the wheel or disc at a 10°-15° angle. If the tool bogs down, use lighter pressure. Keep the tool moving for a smoother surface.
5. Abrasive Cutting-off: Apply the cut-off wheel straight into the work material using only the edge of the wheel. If the tool bogs down, use lighter pressure.

WARNING! TO PREVENT SERIOUS INJURY: Do not grind with the side of the cut-off wheel. Side forces may cause it to shatter.

NOTICE: TO PREVENT TOOL DAMAGE: Use the tool for 15-20 minutes at a time. Allow it to cool completely before next use.

After Use: Turn off the tool. WARNING! TO PREVENT SERIOUS INJURY: Allow the tool to come to a complete stop before setting it down. Unplug the tool. Clean, then store indoors out of children's reach.

Maintenance and Servicing

Procedures not explained in this manual must be performed only by a qualified technician.

WARNING: TO PREVENT SERIOUS INJURY FROM ACCIDENTAL OPERATION: Lock the Trigger and unplug the tool before servicing. TO PREVENT SERIOUS INJURY FROM TOOL FAILURE: Do not use damaged equipment. Have abnormal noise or vibration corrected before further use.

Cleaning, Maintenance, and Lubrication

1. Before Each Use: Inspect general tool condition, checking for loose hardware, misalignment, binding, damaged cords, cracked parts, or any other condition affecting safe operation.
2. After Use: Wipe external surfaces with a clean cloth.
3. Periodically blow dust and grit from motor vents using dry compressed air. Wear safety goggles and breathing protection.
4. WARNING: TO PREVENT SERIOUS INJURY: If the supply cord is damaged, it must be replaced only by a qualified service technician.

Troubleshooting

Follow all safety precautions when diagnosing or servicing. Disconnect power supply before service.

Parts List and Diagram

Parts List

Record Product's Serial Number Here: ________________________ Note: If product has no serial number, record month and year of purchase instead. Note: Some parts are listed and shown for illustration purposes only, and are not available individually as replacement parts. Specify UPC 792363573481 when ordering parts.

Assembly Diagram showing all parts and their connections.

Warranty Information

Harbor Freight Tools Co. warrants this product to be free from defects in materials and workmanship for 90 days from the date of purchase. This warranty does not apply to damage due to misuse, abuse, negligence, accidents, unauthorized repairs, improper installation, normal wear and tear, or lack of maintenance. Harbor Freight Tools is not liable for incidental, consequential, special, or indirect damages. Some states do not allow limitations on incidental or consequential damages, so the above limitation may not apply. This warranty is expressly in lieu of all other warranties, express or implied, including warranties of merchantability and fitness.

To take advantage of this warranty, return the product or part with transportation charges prepaid. Proof of purchase date and a complaint explanation must accompany the merchandise. Harbor Freight Tools will, at its option, repair, replace, or refund the purchase price if the defect is verified. Return shipping costs for repaired products will be borne by Harbor Freight Tools. If no defect is found, or if the defect is outside the warranty scope, the customer will bear the cost of returning the product.

This warranty gives you specific legal rights, and you may also have other rights which vary from state to state.

Contact Information

Visit our website at: http://www.harborfreight.com

Email our technical support at: productsupport@harborfreight.com

For technical questions, please call 1-888-866-5797.

Copyright © 2020 by Harbor Freight Tools®. All rights reserved. No portion of this manual or artwork may be reproduced without the express written consent of Harbor Freight Tools. Diagrams may not be drawn proportionally. Actual product may differ slightly from the product described herein due to continuing improvements. Tools required for assembly and service may not be included.