Once a wheel is laced, the nipples must be turned down equally. Only then can truing and tensioning begin.
You can simply count threads showing outside the nipple entry or employ tools by Eldi, Var, Bicycle Research, Cyclus, or Problemsolvers. You can even make your own.
Today we offer exquisite drivers by BSC. These stainless bits match nipple ends (slotted, square, hex, or squorx), have a set screw to adjust 1.6mm pins, and include spares of each plus a Wera 1.5mm allen key.
All are available in 50mm (standard) or 80mm (for extra deep rims). If you order a set of 3, tell us what combo in the shopping cart notes area. Lacking that detail, we will ship a set of 3 standard length. The driver is easily spun by finger, hand, or drill.
What a magical time to be a builder! Tools like these were only a dream before 2021.