The Forgotten Kerf

Let's say you need to cut three lengths of 1x4 material, each 3 feet long. By happy coincidence you have a 9-foot stick of 1x4, so you quickly measure and mark two lines, and then make your cuts. But when you go to use the pieces for your project, you find that two of the pieces are too short. The reason is that you forgot to factor in the kerf, or thickness of the saw cut.

The kerf is determined by the width of the blade (usually 1/8-in.) but also the wobble in the cut, and the size of any material torn out by the blade. It’s the reason that you have to give a little extra thought to planning your cuts. The good news is that there’s an easy solution to stay ahead of this common mistake: Always measure and mark each cut. (You can use a tape measure, or speed up multiple identical cuts by using a pattern stick or stop block.)

Dangerous Rag Disposal

While we're on the topic of stains and finishes, let's talk about rag disposal. If you're like most people, your first impulse is to chuck a used rag into the trash. The problem is that the oil-based stains and finishes commonly used in woodworking dry through a process known as "oxidation." Oxidation produces heat, and a crumpled rag traps that heat in its folds, letting the temperature build and build. If you're unlucky, the temperature will build high enough to reach the combustion point (which for a cotton rag isn't that high) and then you've got a fire on your hands.

Pro shops have entire rag disposal procedures, but if you're just starting out the easiest process is to simply spread used rags flat or drape them over the edge of a noncombustible item, such as the utility sink. Let them dry until the finish is fully cured, which usually takes a day or two. At that point, it's safe to dispose of them in the trash.

Moisture Mistakes

It can't be stressed enough: wood is a natural material. It will always expand and contract with relation to the temperature and moisture in its environment. Leaving room for expansion and contraction is an important part of building science and furniture construction. When connecting wood items to an existing structure (the most common example is wood flooring into an existing house) this has to be an acclimation period before beginning work.

If you'll be doing multiple projects, you may consider investing in a moisture meter. If you don't have a meter, a 48-hour window is usually plenty of time to allow wood to acclimate to a new environment. It can be frustrating to wait, but it's much more frustrating to see a beautiful woodworking project ruined by an ugly crack.