After the truss rod is set correctly and your nut slots are submitted effectively, saddle height can be changed, if needed. Initially, take some action measurements at the 12th fret on the two outer strings while your guitar is strung up to pitch. I like to determine from the top of the fret to the bottom of the string in 1/64-inch increments. Considering that action should be set relative to how you play, I’ll leave the specifics to you and the manufacturer of your guitar. The average string action of the guitars I set up is 3/32 inches on the bass side and 1/16 inches on the treble side. It is essential to note that to alter your action height at the 12th fret a specific range, you must multiply that number by 2 to find the height to raise it at the saddle. Prior to you decide whether or not to make an adjustment you should also consider that your saddle should fit deep and tight in the slot without wiggle room, that the saddle leading radius must match that of your fingerboard, and that the preferred saddle height need to most likely not typical less than 1/32 inch or more than 3/16 inches above the bridge. Also, if your guitar has an undersaddle pickup, shimming the saddle might alter the method it operates.
To slightly raise your saddle in a pinch, any hard flat product will do. Cutting up an old credit card into strips as wide as your saddle slot works perfectly. For long-lasting saddle shims, wood veneer strips work terrific, and bone saddle shims are also available.
To reduce your saddle, all you need is a pencil and straightedge to mark your saddle and a file and bench vise to eliminate material. If you do not have access to a bench vise, a good flat counter top and some coarse (80 grit) sandpaper will likewise work. It’s easiest to take product off the bottom of the saddle, since it’s flat. You must just take material off the saddle top if you wish to change the top radius or smooth away string wear. As soon as you’ve decided how much to get rid of from the bottom of the saddle, mark the saddle under the low and high strings and link them with a straight line. Then file or sand away the additional material till you strike your line, checking occasionally to make sure the bottom is still square to the sides. To make certain the bottom of the saddle is really flat, you can run it back and forth over some 120 grit sandpaper on a flat surface area. This step is especially crucial for maintaining string balance if you have an undersaddle pickup.