Guitar action has a lot to do with a straight neck. Because the neck of your guitar is adjustable. It needs adjustment from time to time. It has been made of selected hardwood, and it is kiln-dried to insure proper curing. Consequently, the adjustable truss rod both strengthens the neck and facilitates adjustment of a bowed neck. So, adjust the truss rod When your guitar neck Is not straight.
While all guitar necks are subject to great stress as a result of string tension and seasonal change, furthermore, there are times when a neck could take on a slight bow (or warp) or neck hump. This will rarely occur. However, if it does, there is no cause for alarm if you follow the procedure below for proper correction.
truss rod adjustments for a guitar
How to straighten your guitar neck with an adjustable truss rod at the head stock
When Your Guitar Neck Is Not Straight
adjust the truss rod
Straighten your guitar neck
How to straighten your guitar neck with an adjustable truss rod at the head stock
Straighten your guitar neck:
The neck of your guitar is adjustable. It has been made of selected hardwood, and it is kiln-dried to insure proper curing. The adjustable rod both strengthens the neck and facilitates adjustment of a bowed neck.
Because all guitar necks are subject to great stress as a result of string tension and seasonal change, there are times when a neck could take on a slight bow (or warp) or neck hump. This will rarely occur. However, if it does, there is no cause for alarm if you follow the procedure below for proper correction.
adjust the truss rod
Angled Head stock typical of adjustable truss rod location to Straighten Your Guitar Neck (above)
Loosen all strings (it is not necessary to remove strings from guitar). To straighten your guitar neck pull loosened strings to one side so free access to neck adjuster can be gained.
Remove cover (if it has one) so neck adjuster is exposed. Generally it’s an Allen screw or a hex nut.
adjust Guitar action at the truss rod when your guitar neck is not straight
Sight down the neck from the tuners (as sighting a down the barrel of a rifle) in order to see just how much of a bow or hump the neck has taken. Hold the neck up at eye level and sight along the edge of the fingerboard on both treble and bass sides. It best to place a straight edge on the neck during this process. There are special ones made with cut outs for the frets called a Notched Straightedge below. It helps to adjust the truss rod when your guitar neck is not straight.
Adjusting the guitar truss rod to straighten your guitar neck for better Guitar action
adjust the truss rod on your guitar
If neck is bowed, tighten the adjustable nut clockwise
If neck has hump, loosen the adjustable nut counter-clockwise
Place Allen key or hex wrench on guitar neck adjustment nut and turn very gently (small fractions of a turn at a time). Keep checking the neck as you proceed with each nut turn. Once the neck is straight give the adjustment nut a very slight added turn to compensate for the tension the loose stings will add once they are installed and tuned. TIGHTEN for ” BOW ” and LOOSEN for HUMP.
Special Note: Be careful not to tighten the nut too much ( i. e. when it becomes hard to turn ), because it could result in stripping the threads or perhaps even breaking the truss rod.

trussrod view relax and tighten