Why is it important to keep equal number of turns when building a wheel? My first wheelset build here. I am following Sheldon and this guy. They both stress very much to tighten the nipples to an equal length, for example just as the spoke threads stop showing, and the even more carefully, do equal number of turns on each nipple, in small increments.

Building the front wheel I followed this advice and the result was several very tight spokes and a wheel out of true. My next step was basically to make the tension on all spokes equal, and then true the wheel.

The wheel is true now and looks ready for use (dishing error, vertical and horizontal mis-alignment are small).

So why equal number of turns, if in the end equal tension is the desired result? Or did I do something wrong? 

On another note, the rim freshly-purchased, should be true (looks true, and carrying the two rims next to each other, there were no gaps between them, meaning at least sideways being true). So it makes sense to tighten the spokes with equal tension, to avoid twisting the rim, right?

PS: I triple checked that the nipples are well seated into the eyelets and that the lacing pattern is equal everywhere and the same as on an another wheel.
Then you did not follow the advice if you had several very tight spokes.


  The important thing at this stage is to get all 36 spokes to be as
  close as possible to the same setting, all pretty loose.


The idea is a starting point with equal lengths.  And all pretty loose.

On your wheel threads out of site was probably too much of a starting point. 
Once the treads go out of site the only reference you have to one relative to the other is to count turns.