Bumping this back up as I'm looking for something similar (but for a different purpose). I specifically do NOT want it to self level, I just want a plane projected either parallel or perpendicular to a surface. I have the typical construction laser levels from Bosch or Huepar that will "lock", but there is no flat "true" surface on them to reference once locked - Just a bunch of oblique angles and rubber bumpers.
I bought a few of the digital angle gauges with a laser line projecting out both sides and, while good in concept, I need something a bit more accurate.
The red ones were "decent" with reasonably sharp lines at 20 feet, but were 3/8"-1/2" off from left side to right side. One of them had a base that was not flat and rocked so not high confidence which stable point to use.
Angle varied ~0.2 degrees from right side up to upside down.
The green ones were not decent with line widths almost 3/8" wide at 20 feet and were over 1" off from left to right to the center of the line.
To be clear, I didn't have high expectations for them at ~$25/each - just sharing what you can expect if you buy one.
I want a nice sharp line (1/16" wide or less) at 20 feet with an accuracy of <1/16" side to side over that same 20 feet. The plane needs to simultaneously project "forward" and "backward". The application is makeshift wheel alignment for automotive use.
I'm willing to do some machine work and/or fabrication.