Overview. PWLs are valuable tools to own due to their versatility, accuracy, and low cost and offer greater value on larger (5 feet to 200 feet) leveling and flatness projects, because of the time you will save. PWLs are more accurate than 10 arc second machinist levels, exceed the accuracy of 1 and 2 arc second laser trackers at short distances (~3+ feet), far exceed the range of both, and do not require line of sight. They’re also inexpensive, making PWLs an option for shops who also own laser trackers and machinist levels. Click here to watch a video that provides a cost-benefit analysis of the PWL compared to laser tracking systems and machinist levels.
Comparison to Laser Tracking Systems. PWLs cost significantly less than laser leveling systems and take less time to learn how to use. However, if you already own a laser leveling system or need one for applications, such as 3D scanning or determining elevation, then why invest in a PWL? The primary reasons are that PWLs do not require line of sight and do not lose accuracy with distance, which means you’ll save significant time on larger projects. As noted in the cost-benefit analysis video, PWLs can save days, even on modestly sized projects.
Comparison to Machinist Levels. Our low cost PWL model is comparable to the cost of a machinist level, but has higher accuracy and much longer range, which means you’ll save significant time using a PWL on larger projects. As noted in the cost-benefit analysis video, projects that took days with machinist level will take hours with a PWL.
Accuracy and Arc Seconds. To measure accurately you need to use a tool that is more accurate than your tolerance. As a general rule, a tool with 10 times better accuracy is needed to account for errors (human, environmental, etc.). Most laser leveling systems report accuracy in terms of their highest accuracy, which occurs closest to the laser, and in terms of the arc second accuracy of the laser. A highly accurate laser could achieve one arc second of accuracy. This means that in controlled conditions with careful usage the accuracy is .00006 inches at 1 foot, .0006 inches at 10 feet, .0018 at 30 feet, and .0058 at 100 feet. Most machinist levels report accuracy in terms of their highest accuracy, which is across the length of the level and in terms of the arc second accuracy of the level. A high-precision 10 inch or 15 inch machinist level is typically accurate to .0005 inches at the length of the level and to 10 arc seconds if used for longer distances. A High-End PWL is accurate to +/- .0001 inches (+/- .0003 inches with the Standard Kit) at any distance up to its operating range of 200 feet (at 200 feet this is equivalent to .017 arc seconds). In other words, PWLs are more accurate than machinist levels and exceed the accuracy of 1 and 2 arc second laser trackers at around 3 feet.
Saving Time. If your project does not have line of sight or is large and requires high accuracy, then in order to use a laser tracker or machinist level you must move it, taking overlapping measurements as you do so in order to calculate a full set of measurements. Once you’ve taken your measurements and made adjustments to the surface you were leveling or the surfaces you were aligning, you must now retake measurements at the exact same spots to see if your adjustments were effective. With a PWL, you can take measurements, leave the PWL in place while you make adjustments, and retake measurements. On a large project, this can save hours, days, or even weeks of time. This is why PWL users typically see a return on investment within 4 months or on a single project. Click here to watch an animation of this process.