DEWALT DCS391NT-XJ 18V Cordless Circular Saw User Manual

1. Introduction

Thank you for choosing the DEWALT DCS391NT-XJ 18V Cordless Circular Saw. This manual provides important information regarding the safe operation, setup, maintenance, and troubleshooting of your tool. Please read this manual thoroughly before using the saw and keep it for future reference. This circular saw is designed for cutting wood and wood-based materials.

2. General Safety Instructions

WARNING: Read all safety warnings, instructions, illustrations, and specifications provided with this power tool. Failure to follow all instructions listed below may result in electric shock, fire, and/or serious injury.

2.1 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, such as in the presence of flammable liquids, gases, or dust. Power tools create sparks which may ignite the dust or fumes.
• Keep children and bystanders away while operating a power tool. Distractions can cause you to lose control.

2.2 Electrical Safety

• Power tool plugs must match the outlet. Never modify the plug in any way.
• Avoid body contact with earthed or grounded surfaces, such as pipes, radiators, ranges, and refrigerators. There is an increased risk of electric shock if your body is earthed or grounded.
• Do not expose power tools to rain or wet conditions. Water entering a power tool will increase the risk of electric shock.

2.3 Personal Safety

• Always wear eye protection. Use safety glasses, goggles, or a face shield.
• Wear appropriate personal protective equipment (PPE) such as dust masks, non-skid safety shoes, hard hats, or hearing protection.
• Stay alert, watch what you are doing, and use common sense when operating a power tool. Do not use a power tool while you are tired or under the influence of drugs, alcohol, or medication.
• Prevent unintentional starting. Ensure the switch is in the off-position before connecting to battery pack, picking up or carrying the tool.

2.4 Circular Saw Specific Safety

• Keep hands away from the cutting area and the blade. Keep your second hand on the auxiliary handle, or motor housing. If both hands are holding the saw, they cannot be cut by the blade.
• Do not reach underneath the workpiece. The guard cannot protect you from the blade below the workpiece.
• Adjust the cutting depth to the thickness of the workpiece. Less than a full tooth of the blade should be visible below the workpiece.
• Never hold the workpiece in your hands or across your leg while cutting. Secure the workpiece to a stable platform.
• Always use blades of the correct size and type for your saw.
• Never use damaged or incorrect blade washers or bolts.

3. Product Overview

The DEWALT DCS391NT-XJ is an 18V cordless circular saw designed for efficient and precise cutting. It features a durable magnesium base and an all-metal blade guard for job site resilience.

3.1 Components

1. Main Handle
2. Trigger Switch
3. Lock-off Button
4. Blade Guard
5. Blade
6. Depth Adjustment Lever
7. Bevel Adjustment Lever
8. Base Plate (Shoe)
9. Spindle Lock Button
10. Battery Port

Image 3.1: Overview of the DEWALT DCS391NT-XJ 18V Cordless Circular Saw, showing its main components including the handle, blade, and base plate.

4. Setup

4.1 Battery Installation

The DEWALT DCS391NT-XJ operates with an 18V Lithium-ion battery (sold separately). Ensure the battery is fully charged before use.

1. Align the battery pack with the battery port on the saw.
2. Slide the battery pack into the port until it clicks securely into place.
3. To remove, press the battery release button and slide the battery out.

Image 4.1: Underside view of the circular saw, highlighting the battery port where the 18V Lithium-ion battery is inserted.

4.2 Blade Installation and Removal

The saw uses a 165mm diameter blade. Always ensure the saw is disconnected from the battery before changing the blade.

1. Remove the battery pack from the saw.
2. Press and hold the spindle lock button to prevent the blade from rotating.
3. Using the appropriate wrench, loosen the blade retaining bolt by turning it counter-clockwise.
4. Remove the outer flange and the old blade.
5. Clean the inner and outer flanges.
6. Place the new 165mm blade onto the spindle, ensuring the teeth are pointing in the direction of rotation indicated by the arrow on the guard.
7. Replace the outer flange and tighten the blade retaining bolt clockwise. Do not overtighten.
8. Release the spindle lock button.

4.3 Adjusting Cut Depth

The maximum cutting depth at 90° is 55mm.

1. Loosen the depth adjustment lever.
2. Raise or lower the base plate to achieve the desired cutting depth. Ensure only a small portion of the blade teeth extends below the workpiece.
3. Tighten the depth adjustment lever securely.

4.4 Adjusting Bevel Angle

The saw allows for bevel cuts up to 50°.

1. Loosen the bevel adjustment lever.
2. Tilt the base plate to the desired angle, aligning the indicator with the angle scale.
3. Tighten the bevel adjustment lever securely.

5. Operating Instructions

5.1 Starting and Stopping the Saw

1. To start the saw, press the lock-off button (if present) and then squeeze the trigger switch. The saw features an intelligent variable speed switch.
2. To stop the saw, release the trigger switch. The electronic motor brake will quickly stop the blade for added safety.

5.2 General Cutting Techniques

• Always secure the workpiece firmly to prevent movement during cutting.
• Ensure the blade is clear of the workpiece before starting the saw.
• Allow the saw to reach full speed (5150 RPM) before beginning the cut.
• Guide the saw smoothly through the material, maintaining a consistent feed rate. Do not force the saw.
• The saw's base plate and right-positioned blade provide good control and visibility of the cutting line.
• Support the workpiece properly to prevent pinching the blade or causing kickback.

Image 5.1: A user demonstrating the DEWALT DCS391NT-XJ circular saw in operation, cutting a wooden board on a workbench.

Image 5.2: A user wearing safety glasses and a hard hat, operating the DEWALT DCS391NT-XJ circular saw to cut a piece of wood.

6. Maintenance

WARNING: Always remove the battery pack before performing any maintenance or cleaning.

6.1 Cleaning

• Regularly clean the ventilation slots to prevent overheating.
• Use a soft brush or compressed air to remove dust and debris from the tool.
• Do not use water or chemical cleaning agents.

6.2 Blade Care

• Inspect the blade regularly for sharpness and damage. A dull or damaged blade can cause kickback and poor cuts.
• Replace worn or damaged blades immediately.
• The 24-tooth carbide blade is designed for fast, quality cuts.

6.3 Motor Brushes

The DEWALT motor is fan-cooled and features replaceable carbon brushes. If the tool experiences reduced power or excessive sparking, the brushes may need inspection or replacement. This should ideally be performed by a qualified service technician.

7. Troubleshooting

8. Specifications

9. Warranty and Support

9.1 Limited Warranty

This DEWALT product is covered by a limited warranty. For detailed information regarding warranty terms, conditions, and duration, please refer to the warranty card included with your product or visit the official DEWALT website.

9.2 Customer Support

Should you encounter any issues or require assistance with your DEWALT DCS391NT-XJ circular saw, please contact DEWALT customer service or an authorized service center. Contact information can typically be found on the DEWALT website or in the documentation provided with your purchase.