Tool Lab | How To Choose and Use Oscillating Multi-Tools

This article appeared in the Fall 2023 issue of This Old House Magazine.

Oscillating multi-tools have evolved from their humble beginnings as medical devices for removing plaster casts to become indispensable power tools for both professionals and do-it-yourself (DIY) enthusiasts. Due to their ability to perform a wide range of tasks, people often refer to these versatile items as the Swiss Army knives of power tools. The key to their versatility lies in their unique cutting action, which involves a side-to-side wiggling motion of just a few degrees at speeds up to 20,000 oscillations per minute.

Professionals frequently rely on oscillating multi-tools for precise plunge and flush cuts, such as trimming door jambs to accommodate new flooring or cutting receptacle recesses in drywall. However, DIYers have discovered that these tools are equally valuable for detail sanding, metal cutting, caulk removal, and grout grinding. In this guide, we’ll explore how to choose the right oscillating multi-tool and maximize its potential in your projects.

Oscillating Multi-Tools: Features and Upgrades

When selecting an oscillating multi-tool, it’s necessary to consider the following key features:

• Grippy rubber handholds: These enable comfortable use of the tool at multiple angles, reducing fatigue during extended use.
• Mounting plate: This is where accessories attach to the tool. Look for a sturdy, well-designed plate that securely holds attachments.
• Oscillating angle: The side-to-side motion typically ranges between two and five degrees—a larger angle results in more aggressive cutting action.
• Speed control: A dial or switch that allows you to adjust the number of oscillations per minute, providing better control for different materials and tasks.
• Tool-free blade change: A lever locks accessories to the plate, allowing for quick and easy blade changes without additional tools.
• Work light: An LED light that illuminates the work area, improving visibility and precision.

Worthwhile Upgrades

To enhance the functionality of your oscillating multi-tool, consider these valuable additions:

• Accessory kit: This kit will make sure the tool is ready for a wide range of tasks by providing various blades and attachments.
• Battery packs (for cordless models): Additional packs provide longer operation times and less downtime during large projects.
• Case: Keeps the tool and its accessories organized and protected conveniently.
• Dust extractor: An attachment that connects to a shop vac to remove debris, improving visibility and reducing cleanup time.
• Precision blades: Consider investing in precision blades for detailed work that requires more accuracy and finer cuts.

4 Ways To Use an Oscillating Multi-Tool

An oscillating multi-tool’s versatility makes it an invaluable addition to any toolbox. Below are four primary ways to use this multitasker to achieve the best results.

Cutting

Select the appropriate blade for the material you’re working with. Begin slowly to establish an initial cut or kerf, then gradually increase the speed while gently rocking the blade to engage more teeth. Lift the blade up and down slightly to help eject sawdust and maintain a clean cut. 

It’s best to work from the bottom up for vertical cuts to allow sawdust to fall away naturally. Applying masking tape along the cut line can help minimize splintering if you’re working with delicate materials.

Scraping

Begin by placing a piece of laminate or flashing under the blade to protect the surface. Plunge the scraper into the caulk or putty and work the blade left and right, using both the side and tip to remove material efficiently. When using larger blades, operate at medium speed but slow down for better control with narrower blades or in tight spaces. Keep the tool at a shallow angle to avoid damaging the substrate beneath the scraping material.

Grinding

Choose a grit-encrusted blade for removing grout or hardening thinset between tiles. Begin by scoring a light line to guide the tool and keep it perpendicular to the surface to prevent chipping surrounding tiles. As you work, rotate the blade to extend its lifespan and promote consistent performance. For tough materials, using water helps cool the blade and reduce dust during grinding.

Sanding

Carefully monitor your speed, as full-speed sanding can cause finishes to melt and clog the pads. Remember that the oscillating action may leave more scratches than random-orbit sanding, so it’s important to work through sanding pad grits from coarse to fine for smoother results. 

Apply light pressure and allow the tool to do the work to avoid damaging the surface. Make sure the sanding pads are properly aligned on the attachment to prevent uneven wear and improve overall performance.

Tips for Making Cuts With Oscillating Multi-Tools

While oscillating multi-tools are generally safe and straightforward to use, these tips can help you achieve cleaner cuts and extend the life of your blades:

• Know the tool’s limits: Reserve multi-tools for detail work and finishing cuts. Use more extensive tools like circular or reciprocating saws for initial cuts to save time and reduce wear on multi-tool blades.
• Play the angles: Don’t hesitate to rotate the blade or hold the tool in various positions to optimize control and visibility.
• Track your depth: Wrap painter’s tape around the blade to mark cutting depth, especially when working with drywall.
• Use guide blocks: Attach a strip of wood to guide the blade for precise straight cuts in flooring or drywall.
• Watch your speed: Excessive heat can quickly ruin accessories. If you notice smoke, reduce pressure and speed, and lift the tool to clear sawdust from the teeth.

Mastering Essential Cuts

To truly master using an oscillating multi-tool, it’s important to understand some tried-and-true techniques.

Precise Plunge Cutting

To execute a precise plunge cut in materials like drywall, plywood, or flooring, do the following:

1. Start slowly and sink a corner of the blade into the material.
2. Pivot the tool so that the blade rests on your cutline.
3. Gradually work the blade along the line, maintaining a steady hand and consistent pressure.
4. Use a straightedge or guide to help the cut stay true and clean.
5. Keep the tool steady to avoid veering off the cutline.

Making Space for Flooring

When installing new flooring and trimming door jambs or casing, do the following:

1. Use a piece of scrap flooring as a guide for accurate cutting height.
2. Place the blade flat on the scrap piece.
3. Begin cutting from the thinnest molding section and progress to the thicker end.
4. Maintain a steady hand and consistent pressure throughout the cut.
5. Check your progress periodically to confirm the cut remains level and even.

Must-Have Multi-Tool Attachments

To maximize the utility of your oscillating multi-tool, familiarize yourself with the wide array of available attachments. While most tools come with basic accessories, expanding your collection can significantly increase the tool’s versatility.

<strong>For general cutting</strong>: Cutters are indispensable for general carpentry and remodeling tasks. Choose fine-tooth, high-carbon steel blades for wood and plastic, and carbide when you might encounter metal. – Dana Schiffman

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Maintenance and Care for Your Oscillating Multi-Tool

To keep your oscillating multi-tool in top condition and extend its lifespan, follow these maintenance tips:

• Clean the tool after each use, removing dust and debris from vents and moving parts.
• Keep blades and attachments clean and sharp for optimal performance.
• Keep the battery contacts clean on cordless models for efficient power transfer.
• Lubricate moving parts as recommended by the manufacturer.
• Periodically check for loose screws or components and tighten them to prevent accidents.
• Regularly inspect the power cord for damage (for corded models).
• Store the tool and accessories in a dry place to prevent rust and corrosion.

Our Conclusion

Oscillating multi-tools are versatile and invaluable additions to any toolkit, capable of handling a wide range of tasks with precision and efficiency. By understanding the features, techniques, and attachments available, you can maximize the potential of this powerful tool in your DIY projects and professional work.