The Drum Sander: A Tool You Didn’t Know You Needed

What is a Drum Sander?

The drum sander I’m referring to is a large, stationary power tool. It consists of an abrasive-wrapped drum, positioned above a flat conveyor. The gap between the drum and the conveyor belt below it is usually controlled by a handle on the side that rotates to raise or lower the drum; a few sanders raise or lower the conveyor belt. The drum spins at a constant speed, whereas the conveyor has a variable speed control.

For rapid wood removal, I use a faster conveyor speed to reduce the duration of each pass. To refine the surface, I use a slower conveyor speed, which increases the number of rotations of the drum as the stock passes through, creating a smoother surface.

Determining the starting height of the drum is the first step of the sanding process. I do this by setting the drum slightly higher than the stock’s thickness. I start the conveyor and begin feeding the stock.

As soon as it starts passing under the drum, I turn the handle until the drum barely touches the surface. I complete the pass at that height and then repeat it. From that point, I lower the drum between 1/8 and 1/4 turn per pass. Had I lowered it too much—causing it to catch on the stock and risking damage to the wood or motor—an auto-adjusting feature, now standard on most quality sanders, would have slowed the conveyor, permitting successful completion of the pass.

(You may wonder, Why not raise the drum? The reason is that under pressure to act quickly, you may turn the handle the wrong way, which is why this automatic feature is so important.) 

36-, 60-, and 100-grit wraps.

Use a Drum Sander To…

Prepare a figured wood blank for scrolling.

Apply double-sided tape to stabilize a twisted board.

Smooth surfaces on marquetry.

Sand cupped wood convex-side up.

Uses in Scrolling

Drum sanders are typically used for stock preparation, and not for finishing work. However, by using a higher grit wrap such as 220, you can easily and efficiently create a finished surface on your wood before it is cut. This is especially useful for delicate fretwork projects, whose thin bridges are vulnerable to breakage, and also for large blanks that are to be cut into smaller pieces.

You can also use the drum sander to level the surface of an inlay, or give a smooth finish to a puzzle, provided that the puzzle pieces have been secured so that no movement occurs when they are passed under the drum.

Drum Sanders vs. Planers

If you have a planer, do you need a drum sander? Despite some overlap in function, there are significant differences between the two.

Planers reduce stock more efficiently than drum sanders. However, damage to the wood, such as tear-out, can occur if the cutters are dull, or if the wood is highly figured or planed against the grain.

Drum sanders remove stock at a slower pace, even when coarse grits like 36 or 60 are used. The sanding action is gentle and can safely be done with or against the grain, making it the tool of choice for wood with irregular grain patterns and fragile items like thin wood or marquetry.

       Open-end drum sander.

While you can use a jointer or hand plane to flatten the bottom face, the conveyor belt of the drum sander permits a simpler solution.

For twisted wood, I attach pieces of thick double-sided tape under the raised corners to create a stable base. I then sand the wood, tape-side-down, as I would any other board.

The early passes remove only the high spots; the sanding sound is intermittent and distinctive. This sound becomes more regular as the high areas are removed and more of the upper surface can be sanded. A continuous sound throughout the pass signals that sanding is at or near completion.

When the sanded surface is flat, I remove the tape, and repeat the process for the remaining face. Cupped or bowed wood thick enough to resist the drum’s downward pressure can be passed through the sander with the convex side up, with tape added to the bottom corners to correct any twist.

The finished, flattened stock will be thinner than before, but is no longer firewood!

Choosing a Drum Sander

Like all tools, drum sanders vary in price, quality, and ease of use. Fortunately, a number of quality drum sanders are available today to choose from.

Before choosing a drum sander, it’s important to identify which features are most important to you, and which sander is most likely to meet your present and future needs. A quality sander isn’t cheap. However, this is likely a one-time purchase, and nobody can afford an inexpensive tool that brings grief whenever you use it.

Drum sanders appropriate for the home shop come in a variety of sizes and configurations, from 10″ (25.4cm) tabletop models to 19″ (48.3cm) floor-mounted units. Drums, made of aluminum, are usually 5″ (127mm) in diameter.

Most sanders are open at the outer end, which doubles the maximum width of stock that can be sanded; better quality sanders have an adjustment that lowers the outboard edge just enough to prevent ridges when the second pass is made.

Open-end sanders are identified by two numbers, such as 16-32. The first number is the length of the drum, reflecting the maximum width that can be sanded in a single pass; the second is the maximum width that can be sanded in two successive passes, one for each half of the workpiece.  

Adjustment lever for sanding wider boards.

Drum sanders also vary in the maximum stock thickness they can handle; 3″ (7.6cm) and 4″ (10.2cm) limits are typical. Most can sand stock down to 1/32″ (1mm), perfect for making veneer from resawn wood, and most can pass pieces as short as 2 3/8″ (6cm) through the drum. Infeed and outfeed tables, available as options, facilitate the feeding of long boards and help prevent gouging at their ends.

If shop space is limited, look for models with tables that fold down when not in use.

If you’re likely to sand both thick and thin wood, a sander with a quick-adjust lever that rapidly raises or lowers the height of the drum can be a real time and wrist saver; if precision is critical, consider a model with an integrated digital readout. And, if you anticipate sanding with several different grits, be sure that the clamps that secure the ends of the wrap are easy to use.

This makes changing the wrap quick and easy for hands of every size and strength level.

A well-designed sander should be easy to maintain, with components that are accessible if adjustment or repair is needed.

Tech support staff should be knowledgeable and replacement parts readily available.

Drum sander clamp for abrasive wraps.

Conclusion

My experience with the less satisfactory drum sanders of the past has helped me appreciate the quality of those currently available. Aside from my scroll saw, my drum sander is among the most valuable and frequently used tools in my shop.

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