RYOBI 1/3 Sheet Sander Model S631DK Instruction Manual
Model: S631DK
Brand: RYOBI
1. Product Overview
The RYOBI 1/3 Sheet Sander (Model S631DK) is engineered for efficient and smooth sanding tasks. It features a robust 1.8 amp electric motor, delivering 12,000 orbits per minute (OPM) for effective material removal. The ergonomic overmold handle provides enhanced comfort during prolonged use. Its design facilitates flush sanding on three sides, making it suitable for corner sanding and working against walls. The integrated cyclonic action dust collection system is designed for maximum dust pick-up, contributing to a cleaner work environment.

This image displays the Ryobi 1/3 Sheet Sander, highlighting its ergonomic handle, sanding pad, and transparent cyclonic dust collection box.
2. Important Safety Instructions
Always follow basic safety precautions when using this power tool to reduce the risk of fire, electric shock, and personal injury. Read all instructions before operating.
General Power Tool Safety Warnings:
- Work Area Safety: Keep your 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.
- Electrical Safety: Power tool plugs must match the outlet. Never modify the plug in any way. Do not use any adapter plugs with earthed (grounded) power tools. Avoid body contact with earthed or grounded surfaces such as pipes, radiators, ranges, and refrigerators.
- Personal Safety: Always wear eye protection. Use hearing protection when operating for extended periods. Dress properly; do not wear loose clothing or jewelry. Keep hair, clothing, and gloves away from moving parts. Stay alert, watch what you are doing, and use common sense when operating a power tool.
- Tool Use and Care: Do not force the power tool. Use the correct power tool for your application. Disconnect the plug from the power source before making any adjustments, changing accessories, or storing power tools. Store idle power tools out of the reach of children and do not allow persons unfamiliar with the power tool or these instructions to operate the power tool.
- Service: Have your power tool serviced by a qualified repair person using only identical replacement parts. This will ensure that the safety of the power tool is maintained.
3. Components
Familiarize yourself with the main components of your RYOBI 1/3 Sheet Sander for proper operation and maintenance:
- Sanding Pad: The rectangular base where sandpaper is attached.
- Paper Clamps: Mechanisms on the front and rear of the sanding pad used to secure sandpaper.
- Dust Collection Box: A removable container designed to collect sanding dust via cyclonic action.
- Power Switch: Controls the ON/OFF function of the sander.
- Ergonomic Handle: Designed for comfortable grip and control during operation.
- Power Cord: Connects the sander to an electrical outlet.
4. Setup and Assembly
4.1 Attaching Sandpaper
- Ensure the sander is unplugged from the power source to prevent accidental startup.
- Locate the paper clamps on the front and rear of the sanding pad. Press the levers to release the clamps.
- Insert a standard 1/3 sheet of sandpaper under the released clamps, ensuring it is centered and taut across the sanding pad.
- Securely close the paper clamps by pressing the levers back into their locked position. Verify the sandpaper is held firmly.
4.2 Attaching the Dust Collection Box
- Align the opening of the dust collection box with the exhaust port located at the rear of the sander.
- Push the dust collection box firmly onto the port until it clicks securely into place. Ensure a tight seal for effective dust extraction.
5. Operating Instructions
5.1 Powering On/Off
- Connect the sander's power cord to a suitable 120V AC electrical outlet.
- To turn the sander ON, locate the power switch and press it to the 'I' (ON) position.
- To turn the sander OFF, press the power switch to the 'O' (OFF) position.
5.2 Sanding Techniques
- Always hold the sander firmly with both hands during operation.
- Place the sander flat on the workpiece surface before turning it on.
- Move the sander in long, overlapping strokes, applying even, light pressure. Avoid pressing down too hard, as this can reduce sanding efficiency, cause swirl marks, and potentially damage the workpiece or the sander.
- For optimal dust collection, ensure the dust box is properly attached and emptied frequently.
- When sanding corners or against walls, utilize the sander's flush sanding capability on its three sides.
6. Maintenance
Regular maintenance ensures the longevity and optimal performance of your sander. Always unplug the tool before performing any maintenance.
6.1 Cleaning
- Wipe the exterior of the sander with a clean, damp cloth. Do not use harsh chemicals or abrasive cleaners.
- Periodically clear any dust or debris from the ventilation openings to prevent overheating. Use compressed air if necessary.
6.2 Dust Collection Box
Empty the dust collection box frequently, especially during extended use, to maintain effective dust extraction. To empty, detach the box from the sander, discard the collected dust, and reattach it securely.
7. Troubleshooting
Refer to the table below for common issues and their potential solutions:
| Issue | Possible Cause | Solution |
|---|---|---|
| Sander does not turn on. | No power supply; Power switch in OFF position. | Check power cord connection and outlet; Ensure switch is in ON position. |
| Poor sanding performance. | Worn sandpaper; Excessive pressure; Incorrect grit. | Replace sandpaper; Apply lighter, even pressure; Use appropriate grit for the task. |
| Excessive vibration. | Sandpaper not properly secured; Damaged sanding pad. | Ensure sandpaper is taut and clamps are locked; Inspect sanding pad for damage and replace if necessary. |
| Ineffective dust collection. | Dust box full or improperly attached; Blockage in exhaust port. | Empty dust box and reattach securely; Clear any blockages from the exhaust port. |
8. Specifications
| Feature | Specification |
|---|---|
| Brand | RYOBI |
| Model Number | S631DK |
| Power Source | Corded Electric |
| AC Adapter Current | 1.8 Amps |
| Voltage | 12 Volts (DC) |
| Maximum Rotational Speed | 12,000 OPM (Orbits Per Minute) |
| Grit Type (Included) | Medium (80 Grit) |
| Item Weight | 3.85 pounds |
| Package Dimensions | 12.32 x 6.85 x 4.29 inches |
| UPC | 033287160303 |
| Date First Available | August 24, 2020 |
9. Warranty and Support
For detailed warranty information, product registration, or technical support, please refer to the documentation included with your RYOBI 1/3 Sheet Sander. You may also visit the official RYOBI website for further assistance. Please retain your purchase receipt as proof of purchase for any warranty claims.







