Quick Tips — Questions & Answers 7

Clean-cut dovetails

Q: I’m a novice at cutting dovetails and can get them only to the point of a rough fit. My problem is in cutting away the waste between both the tails and the pins. How do I do that to make the fit clean and sharp?

A: START BY DEFINING THE TAILS AND PINS with backsaw cuts. Then remove most of the waste between tails and pins with a coping saw. If you used a Japanese pullsaw and the kerf is too thin for the coping-saw blade, make a second cut with the pullsaw to remove a wedge, creating more space.
I use a Stanley #15-057 extra-narrow blade to cut away the bulk of the waste. Whatever blade you use, orient it 45° in relation to the coping saw’s back. This helps keep the back from snagging on the workpiece during the cut.

Hold the blade about 1⁄8 in. above the baseline and begin the cut by twisting the saw’s handle slightly so that the blade teeth bite into the side of the kerf. Then make several strokes back and forth while turning the handle—not to advance the cut, but to rotate the blade into a horizontal orientation. Then complete the cut.

Try to leave 1⁄32 in. to 1⁄16 in. of waste inside the baseline. That’s just enough for the chisel to bite into as you complete the process by paring to the baseline. To keep the baseline really sharp, chisel halfway in from each face of the board, starting on the inside and finishing from the outside.

A backsaw makes the initial cuts. If you use a thin-kerf, Japanese saw instead, you might need to make extra cuts to make room for the next step.

A coping saw cuts out the waste. Setting the blade at a 45º angle makes it easier to turn the sharp corner at the bottom of the backsaw cut and cut the waste away. Leave about 1⁄16 in. of material above the baseline. Pare it away with a narrow chisel to complete the process.

Lumber rack on wheels

Q: Is it possible to get further details about the sheet-goods rack?
A: I start by attachInga four-sided frame to the base assembly. I cover the frame with 1⁄2-in. plywood, then attach the sides, separat-ing them at the top with a solid-wood strip. The outside edges of both the base frame and the top strip are beveled to match the slope of the sides.

The tapered blocks at the bottom of the sloped sides leave space under the sheets for lifting. The taper of the blocks creates a 90° angle with the sloped sides. I added a cover strip to the blocks on one side in order to store smaller pieces of plywood.

The stiffeners are attached to the sides before the sides are attached to the top strip and the bottom frame.

I used drywall screws for most of the assembly, and no glue at all.

More on shop noise

Q: How do I determine the noise level of two tools running together? And what is the noise reduction of earplugs and muffs worn together?

A: accordIng to Les bLomberg , director of the Noise Pollution Clearinghouse, if one machine is at least 10 decibels louder, or twice as loud as another (decibels are on an exponential scale), then the noisier machine sets the resulting level. If the machines are about equally loud, then their combined sound level is a bit greater than the louder one. For example, two machines that each generate roughly 90 db. of sound produce 93 db. together, the equivalent of a 30% increase.

Bear in mind that the louder the sound, the less time you safely can be exposed to it without protection.
As for combining hearing protectors, research indicates that the practice would serve little or no purpose for wood -workers. Earplugs with muffs, for instance, are only mar-ginally superior to plugs or muffs alone.

Two loud machines, one set of earmuffs. This jointer/dust collector combina -tion is noisy, but only a bit more so than the louder machine. One good set of muffs or plugs provides all the protection your ears need.

The clearest finish

Q: I want to keep my spalted maple looking as natural and non-yellow as possible. What finish should I use?

A: Maple has a tendency to yellow over time no matter what finish is used. However, you have a choice of finishes based on how much handling the piece is likely to get.

If you want to give the wood some protection but still stay close to an in-the-wood look, I suggest you apply two or three coats of a non-gloss water-based finish, sanding with P220-grit sandpaper after the first and second coats.

If a non-film oil finish is more important to you, try either Minwax’s or Watco’s Wipe-On Poly, both of which are among the clearest of this type of product. However, either one will yellow the wood more than the water-based finish, and you won’t be giving the wood much protection.

Spalted or not, maple tends to yellow over time. The question is: What finish minimizes the yellowing?

Brush on a waterborne finish. Two or three coats of a clear, non-glossy, water-based polyurethane will give the spalted maple a protective coat but keep the wood’s natural look.