"This article describes how to assemble an inexpensive, but very accurate, wheel building stand for bicycles. The stand uses a dial gauge indicator that is accurate to 1/1000th of an inch, but the complete stand can be finished for about $100. The low price is achieved by using inexpensive options for the primary parts: the overall platform of the tool, the wheel holding mechanism, the dial gauge, and the magnetic base for the gauge. With some practice, you can build or adjust wheels to within +/- .005 inches, for both roundness and trueness. Wheels with this accuracy ride nicely. With good wheel parts, and a little luck, you can create a wheel that is +/- .002 inches, in both measurements. These finished wheels are so straight that the rims look like a mirror when you spin them. Because this tool is so inexpensive, you might want one even if you are only purchasing wheels. For example, a racing team might use it to check that all wheels they buy are within +/- .005, and then discard any used wheels that are worse than +/- .020 out of round or true. My thanks to Peter Askin of Specialty Mechanics for helpful design discussions about dial gauges and magnetic mounting."
You can buy a basic truing stand for a lot cheaper than that. Nobody needs 1/1000 of an inch accuracy in truing wheels. With a high quality rim I can usually get my wheels true and round to well within a mm with a basic truing stand. Its absurd to think that you can get your wheels perfectly true and expect them to stay within 1/1000th of an inch. No rim is perfectly true and round to begin with and bike wheels don't spin nearly fast enough for microscopic variations in roundness and trueness to matter.