Je déterre le post car il m'intéresse (normal, j'ai une Strat standard US à régler )
J'ai fait qlq recherches et j'ai trouvé ça sur la version américaine du site de Fender :
"SHIMMING/MICRO-TILT™ ADJUSTMENT
Shimming is a procedure used to adjust the pitch of the neck in relation to the body. A shim is placed in the neck pocket, underneath the butt end of the neck. On many American series guitars, a Micro-Tilt adjustment is offered. It replaces the need for a shim by using a hex screw against a plate installed in the butt end of the neck. The need to adjust the pitch (raising the butt end of the neck in the pocket, thereby pitching the neck back) of the neck occurs in situations where the string height is high and the action adjustment is as low as the adjustment will allow.
To properly shim a neck, the neck must be removed from the neck pocket of the body. A shim approximately 1/4" (6.4 mm) wide by 1 3/4" (44.5 mm) long by .010" (0.25 mm) thick will allow you to raise the action approximately 1/32" (0.8 mm). For guitars with the Micro-Tilt adjustment, loosen the two neck screws on both sides of the adjustment access hole on the neckplate by at least four full turns. Tightening the hex adjustment screw with an 1/8" hex wrench approximately 1/4 turn will allow you to raise the action approximately 1/32". Re-tighten the neck screws when the adjustment is complete. The pitch of the neck on your guitar has been preset at the factory and in most cases will not need to be adjusted.
Note: If you feel that this adjustment needs to be made and you're not comfortable doing it yourself, take your guitar to your local Fender Authorized Dealer."
D'après mon niveau d'anglais (un peu limité dès le langage est technique), il faut d'une part se procurer la bonne clef allen (on ne fonctionne pas avec le système métrique chez Fender,...), d'autre part procéder en dévissant un peu la plaque. Et comme d'habitude on commence avec un quart de tour, faut pas y aller comme un bourrin.
Pour confirmation, j'en appelle à l'intervention d'un anglophone confirmé et/ou à qlq'un d'expérimenté en réglage de Fender.