Kay "Kanti Lever" Truss Rod Flier

An original flier from a 1950s Kay Archtop with the Kanti-Lever truss rod system

I went ahead and transcribed the letter for your reading pleasure.

HOW TO USE YOUR "KANTI LEVER" ADJUSTABLE GUITAR NECK

Your new guitar is equipped with a balanced tension neck. The purpose of this adjustable feature is to enable you to keep your guitar neck in perfect alignment at all times.

Having been made very thin to permit fast, tricky progressions, the wooden neck is subject to atmospheric conditions. These atmospheric conditions, plus the tension of the strings, tend to warp or bent the necks. In addition, the alignment of the neck is affected by a change in pitch, change of strings, and a change of bridge height. You can now keep your neck in perfect alignment with Kay's ingenious "Kanti Lever" reinforcement inside the neck. Built around the lever principle, with a specially alloyed steel truss rod and a positive screw adjustment, this neck is now virtually fool-proof.

Your guitar neck was perfectly aligned when it left the factory. Should any further adjustment be needed, you can do it yourself with the handy "T" wrench that was included. Insert the wrench in the hole in the heel of the neck (where the neck joins the body) turn the key to the right (clockwise) to adjust the neck back; turn the key to the left (counter-clockwise) to bring the neck forward. Ordinarily, a turn or less will put your instrument back in perfect alignment. Do not readjust the neck unless it proves necessary. Be sure your guitar is in tune before readjusting the neck.