A Homemade PVC Alignment Gauge

Edge Marking Gauge

• An edge marking gauge is a traditional tool in woodworking. It is made from a length of square wood with a ruler scribed on it. It is about a foot long with a wooden disc or collar slid over the rule. A finger-tightened screw is then threaded into the gauge's collar. When tightened, the collar is held fast to the rule and can be slid along the edge of a flat surface. A small point protruding from the end of the rule then scribes a fine line into the surface (often wood), making a line that is perfectly aligned and equidistant from the edge of the material. This same design can easily be rendered in PVC, which will have the added benefit of being waterproof.

Spacing Gauges

• An alignment tool like a spacing gauge doesn't have to make a line. It can be used to measure and align the distance between two objects -- often when building something. For example, two such marking gauges, or similar designs, could be used to align two boards. The PVC spacing gauges would be used to ensure the distance was the same in two different places, aligning them parallel.

Triangle Alignment Tool

• Using straight lengths of PVC, PVC connectors, simple hardware and a little geometry, you can make all kinds of alignment tools for triangles. Two straight lengths can be hinged by through-bolting them. Connectors can be trimmed so they slide over the outside of the PVC pipe. A third straight length can be added connecting the two sliders. This gives you an adjustable triangle you can use for a variety of alignments using the rules of geometry. For example, you know if you adjust two of the three lengths of the triangle the same distance from a corner, that corner will be a right angle.

Square Alignment Tool

• Another way to use PVC for an alignment tool is to create an adjustable parallelogram. Use two equal lengths of PVC tubing, and slide two sliders over each length of tubing. Connect the sliders with smaller diameters of PVC in a crisscross or "X" fashion. Through-bolt the center of the "X", fixing it in place. Affix one of the sliders on each of the larger diameter PVC lengths. When these straight lengths of PVC are moved apart or closer, they will remain parallel. To ensure your alignment tool slides smoothly, consider using some silicon spray.