How is it that finish carpenters do trim jobs daily without suffering angle-induced embolisms? Easy—because they rely on miter guides, not their eyeballs, to tell them where to cut. Likewise, framing carpenters use squares to determine the angles for rafters, rakes, and stair stringers; and furniture makers consult their protractors before laying out dovetails. The right angle-finding tool is your protection against loose joinery and expletive-filled outbursts, whether you're doing something big like building a garden shed, or simply tackling around-the-house maintenance tasks like measuring for a storm window.
So before you make another unsightly cutting mistake, put down that caulk tube and pick up one of the tools. The old adage—"Measure twice"—still applies. But you also need to know the angles.
The aluminum Pivot Square has a locking, adjustable leg that firmly holds any angle from 0 to 90 degrees, so you can make repeated, consistent mark or guide your circular saw through marks or guide your circular saw through angled crosscuts. Spirit vials help you check for level, as when establishing the angle to cut siding where it meets a roofline. About $84, C.H. Hanson