The workmanship of old-school woodworkers always amazes me. Angle tasks were achieved manually with great care and precision, without the use of power tools.
Luckily, today’s contractor and DIYer have access to many modern tools. Advances in technology have also eased most complex mitering tasks, provided, of course, you know how and when to use the proper tool.
Traditionally, a hand-held angle square or contractor’s protractor can be used to determine angles. Several years ago, however, I added an instrument to my tool arsenal that has become invaluable — the digital angle level.
Baseboards that continue up and along a staircase can be tricky — not only must you cut several short sections of baseboard intended to follow the contour along the leading edges at the top and bottom of the stairs, these sections must meet and fit together without any gaps along the miter cuts. The digital angle level makes this process almost trivial, once you get the hang of it.
Granted, this instrument can be used as a level, but it is essentially a digital protractor that provides a digital readout of the measured angle, to the nearest tenth of a degree. The baseboard which rises from the floor, along the front edge of the first stair at a perpendicular (90 degrees), dictates that both the baseboard section along the floor and the short baseboard section that rises will require that each board will be cut at a 45-degree miter (two 45s make a 90). The next cuts are trickier — the rise and run of your stairs establish a pre-set slope along the entire staircase.
In order to determine the miter-cut angles for each of the baseboard sections where the top edge of the short perpendicular baseboard and the longer baseboard meet, the slope angle must be determined. By placing one arm of the digital angle level perpendicular to the floor, and opening it until the other arm is in line with the slope of the staircase, the initial angle measurement is rendered. This established angle should be greater than 90 degrees. Keep in mind — this obtuse angle is not yet the desired measurement — the acute angle, calculated by subtracting the obtuse angle from 180 degrees (the offset from vertical), is what is needed. The resulting acute angle (less than 90 degrees) is then divided by two, because there are two baseboard sections which meet. For example, the top of my staircase to the second floor of my house provides an obtuse angle of 139.8 degrees, providing an acute angle of 40.2 degrees. Each baseboard section was mitered to a 20.1-degree junction angle. I know, this all sounds quite complicated, but it really is quite simple, and systematic after the first few cuts.
Although I’ve used this handy little device primarily for the installation of baseboards, casings and crown mouldings, its versatility truly knows no bounds. Cutting drywall, for example, in a room where the ceiling meets two walls at a slight angle: simply open the digital angle level along each wall face, scribe the angle to the drywall and cut. The drywall will fit snugly every time.
More recently, this indispensable little device has been very useful on several deck builds, primarily when there are complex wraparound stairs. Despite my best efforts, lumber is fickle and will twist and warp, bend and bow as it dries out. Although the framework may have been constructed on a "square" basis, things may shift slightly once the lumber begins to dry out, as soon as the very next day. This can be problematic. Even with the best intentions to construct a "square" deck framework, the "true" angle measurements may be out slightly, having increased or decreased by a degree or two, here and there. With precise measurements, the required miter angles for either stair-tops or fascia can therefore be calculated with the digital protractor. After all, mitering discrepancies along the depth of a two-by-10 will be noticeable — the angle accuracy provided by the digital protractor will greatly reduce the potential for visible gapping along your mitered joints, a sought-after result.
When installing pre-primed trim, and the intention is to paint the trim completely, it is viable to cheat a little when some of the mitered cuts join imperfectly, by adding caulk to the joint line prior to continuing onto the painting step. However, when natural wood is used for trim — and in a greater sense when wood, or composite for that matter, is used to finish the top-decking and fascia of a deck build — the importance of carefully orchestrated mitered cuts increases tenfold. With no way to cheat, improperly cut miters will always appear as a "flaw" in the workmanship.
Angle accuracy is the key to a successful project with complex mitered joints — the digital angle level increased my mitering confidence after the very first use. And now, I never proceed without it.