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My first encounter with construction lasers was 20-plus years ago on a commercial job site, where a subcontractor was using a rotary laser to level the track for a suspended ceiling. The tool obviously saved a lot of time, and even though it could only shoot level, I was jealous that my company couldn't afford the $3,000 it cost to buy one. Since that time, lasers have fallen greatly in price and become much more versatile. I now own several and can't imagine trying to compete without them.
For this article, my crew and I tested a type of line laser that didn't exist until several years back. The industry hasn't created a name for these tools; I like to think of them as combination lasers, because they combine the functions of a cross-line laser with those of a plumb bob: They project visible plumb and level lines, and plumb points up and down. With the right combination laser, a contractor may be able to perform all of his leveling and layout tasks with a single tool.
We tested nine combination lasers, one from each of the companies (two from Topcon) that currently make them: the Agatec CPL 50, Bosch GLL3-80, Hilti PMC 46, Johnson 40-6662, Leica Lino L2P5, Pacific Laser Systems (PLS) HVL 100, Spectra Precision 5.2XL, Topcon LC-2, and Topcon LC-4X.
Laser models change quickly, so there may be additional ones on the market by the time this story comes out.Multiple Functions
All the lasers we tested perform the standard functions of line lasers – projecting horizontal lines that can be used to level deck ledgers, windows, and cabinets; and vertical lines that can be used to plumb door casings, posts, and the like. The lines meet at a 90-degree angle and can be used to project square layout onto plumb surfaces like walls. On a number of models, the beams fan out far enough to project square layout across the floor, up the wall, and onto the ceiling.
Among the qualities that set combination models apart from standard line lasers is their ability to project points straight up and down, so that they can be used in place of a plumb bob. A combination laser is faster and easier to use than a plumb bob; it can be operated by one person and is unaffected by wind. The plumb points appear as single laser dots or as the intersections between laser lines above and below the device. We use the plumb bob function to locate can lights – we lay out their locations on the floor and then carry those marks up to the ceiling. When framing, we use it to plumb walls by checking the alignment of top plates over bottom plates.
With most models, the self-leveling function can be disabled so that the tool can project sloped lines and square layout that isn't plumb or level. This function comes in handy for tasks like laying out stair rails and setting wall tile on the diagonal.