Tips for How to Use a Dual Action Sander

The exact sander that you choose for sanding tasks will vary depending on the needs of the project. But, if you need to sand and buff at the same time you may want to choose a dual action sander. This tool combines the best functionality of a belt and disc sander in an easy-to-form factor.

Lady sanding with a dual action sander

A dual action sander moves back and forth like a belt sander, but there is a light rotary action for buffing. This means that a dual action sander can remove a lot of material quickly including higher bumps on a flat surface. They are powerful tools, and if you sand aggressively they can leave scratches on the surface like a belt sander.

A dual action sander has a slight wobble like a disc sander which prevents the sandpaper from digging into the surface. In this article, we will look at some tips for how to use a dual-action sander safely.

Safety Precautions When Using a DA Sander

When you’re learning how to use a dual action sander there are ten important safety tips that you need to follow. They are:

●      Wear adequate eye and ear protection and a suitable dust mask and if you’re doing a lot of sanding switch to a respirator.

●      When you start the sander the disc must get up to speed before you feed the work-piece.

●      Don’t turn on the power with the stock in contact with the disc until you’re more experienced using a dual action sander.

●      Don’t reach over or around the disc when the sander is running.

●      Use a worktable for sanding and add an extension table if you need it.

●      Don’t sand unless you have a worktable to support the wood.

●      Sand with the downward motion of the disc to avoid kickback and keep the workpiece stable against the worktable.

●      Don’t sand the end grain of ¾ inch stock that’s wider than 5½ inches or the disc rotation may lift the board away from the worktable.

●      Maintain 1/16 inch maximum clearance between the sanding disc and the worktable unless the quill is needed to advance the disc which requires a ½ inch clearance.

●  When you quill feed, attach the feed lever to the side of the power plant where it’s easy to reach.

Choosing the Right Sandpaper

The type of abrasive material and the grit density both have a huge impact on a sanding project. Certain grit grain types are well suited to smoothing and sanding various materials, including woods, metals, and more.

So, when you’re choosing sandpaper, check the coarseness level and grade on the packaging. This is a range of grit sizes that will be effective for similar sanding tasks. It’s pretty common to require a certain level of coarseness rather than a specific grit for your project.

Let’s take a look at the various sandpaper coarseness levels in more detail:

1.    Extra Coarse Sandpaper

Different sizes of Grit sandpaper

This sandpaper is in the 24-grit up to the 36-grit range, and it’s designed to remove tough varnish and paint coatings. Sanding older floorboards often starts at this grit level where extra abrasiveness is essential. This sandpaper should only be used on the hardest-to-remove materials.

2.    Coarse Sandpaper

This is sandpaper in the 40-grit to the 50-grit range, and it’s designed to roughly shape wood and remove any light coats of finish such as polyurethane.

3.    Medium Sandpaper

This ranges from 60-grit up to 100-grit, and its purpose is primarily rough wood sanding and some final shaping. Medium sandpaper is one of the best options to remove planing marks.

4.    Fine Sandpaper

A fine sandpaper can range from 120-grit up to 220-grit, and in many basic workshops, this is all that’s needed for final project sanding.

5.    Extra Fine Sandpaper

This sandpaper has a grit of 240, 320 or 400, and even 600 which is typically defined as “superfine” sandpaper. These are designed for use between coats of varnish or paint and final polishing jobs to get a professional finish.

Attaching sandpaper to a dual action sander

Locate the clip on both sides of the base plate. This may be a spring-loaded or lever-operated clamp system that holds the sandpaper in place. Place the fresh sandpaper into one clamp, stretch it across the base, and insert it into the second clip.

You may need to fold the ends by ¼ inch if the sander base is shorter than the sandpaper. The sandpaper should not be loose because it can tear quickly as you sand and degrade the sanding performance.

Operating the Dual-Action Sander

Two simple principles to get the most out of this versatile power tool:

1.    Apply Even Pressure

It’s tempting to apply more pressure to sand quickly with a dual action sander. But, the weight of this power tool is almost always sufficient to facilitate proper sanding. If you do have a lightweight model it is necessary to apply a little even pressure when sanding.

If you apply too much pressure you can slow down the process and even cause the machine to stall. The abrasive is likely to leave behind swirl marks that can be seen after painting, staining, and finishing. Uneven excess pressure can damage the bearing in your dual action sander leading to an earlier-than-expected replacement.

2.    Avoiding Swirl Marks

Sander on table ready to go

When you’re more experienced using a dual action sander, you can start it up on the work-piece to minimize the risk of gouging the wood.

A common technique is referred to as “start on and stop off” which takes practice. Avoid sanding at an angle because the gouges can be very difficult to remove.

Also, sand in an overlapping manner along with the grain of the wood, and don’t overuse worn-out sandpaper.

If you over sand in a single area, the finish will be altered, and this will be very noticeable when varnish or paint is applied. The entire surface must be sanded evenly to prevent spotting and blotching.

Maintenance and Care of the Sander

The best way to lubricate a dual action sander is to use an automatic lubricator that delivers the correct amount and weight of air motor oil. If you choose to manually lubricate, apply 2-3 drops during the course of the day into the air inlet. Remove the muffle when you apply oil to prevent clogging issues later. Apply the oil in an enclosed area to prevent the re-circulation of exhaust air into the sander. Clean and replace the exhaust muffler elements are required and don’t operate a dual action sander without one.


We hope that these tips for how to use a dual-action sander efficiently and safely have been useful. A dual action sander is a versatile sanding tool, and most workshops have one. Make sure that you use the correct abrasive for the task at hand, and the sanding process will be easier. Start the sander on the surface and turn it off when you lift it off when you have more experience, and you can prevent swirls that mark the surface.