If you've ever swapped a neck on a bolt on style guitar then chances are that you've encountered a common problem. You may find that the angle or pitch of the neck has changed. The string height is now too high and the saddles cannot be lowered. I've seen it when using parts from different mfgs. but it can happen with parts supplied by the same mfg.

 The most common solution is to place a shim under the heel of the neck where it butts againt the neck pocket. This places negative pitch on the neck (creating a downward angle) and lowering the string height. You then fine tune the height with the string saddle adjustments. I've seen everything from match book covers to guitar picks used as shims. This is a quick fix, works well and you can do it at your kitchen table.

 Using a shim leaves an air gap between the neck and the body which many feel reduces the transfer of energy thereby negatively affecting the guitars tone. I'm not sure if I could tell the difference but the theory seems sound and the fact is a well built guitar should not have to be shimmed.

  If you are installing an unfinished neck then you can readily correct the neck pitch. String the guitar up and check the string height. Lower the saddles completely. If the strings are still too high then loosen the strings and unbolt the neck. Cut some shims using milk jug plastic, match book cover or use a guitar pick. You may have to experiment to find the correct thickness. The idea is to adjust the pitch (with the shim thickness) so that when the saddles are at their lowest position the strings will  buzz on the upper frets when picked individually. You can then adjust the string height with the saddles with the minimum adjustment. The lower the saddles the more stable the bridge will be. If you add too much shim then you will have to raise the saddles much higher.

  You will need:

• 8" bench or machinst vise. A machinist vise applies clamping pressure more evenly than a bench vise but either will work.
• 1/8' rubber sheet. You can find this at the hardware store for a few bucks.
• 2 wood shims. You can buy a package at the hardware store for $1.00
• Straight edge ruler and feeler gauge
• Belt sander or sanding block
• 120 Sandpaper

Cut 2 pieces of the rubber sized to match the jaws of the vise. Glue these pieces to the jaws using either silicone or contact cement. Score one side of each piece with a box knife. This will help the adhesive to grip the rubber. 

Before removing the neck from the guitar draw a pencil line across the heel of the neck at the point where it extends beyond the neck pocket. Place the heel of the neck in the vise with the heel facing up. Note: Positioning the neck in the vise is much easier with another pair of hands. Position the neck so that the butt is flush with one end of the jaws. Snug the neck up a little. The heel of the neck is tapered so you will need to place shims at the front in order to get good clamping action. Position the heel so that the top of the butt end is level with the top of the jaws. Adjust the front of the heel so that it rises above the level of the jaws by the thickness of the shims you used to adjust the neck. This is typically .030 - .060". Place a straight edge ruler across the butt end of the neck and make sure it is flush with the top of the jaws. Next place the ruler across the line you drew on the neck. Use the feeler gauge OR the shim you used to check the gap between the ruler and the top of the vise jaw. This is the amount of wood you need to remove from the heel. Tighten the vise so that the neck is firmly clamped. Check the neck posistion to make sure the position has not changed when you tightened the vise.

Bring a belt sander with a 120 grit belt across the top of the heel until the entire clamped surface is level with the jaws of the vise. You have now lowered the pitch of the neck to the correct angle. Re install the neck, string the guitar and check the results. If you find that the pitch is still too high then repeat the process. Patience is the keyword here. It is better to take off too little than too much.

* You can perform this task on a finished neck however you will have to refinish the area that you removed the wood from. Take care not to sand beyond the point at which the neck leaves the neck pocket to lessen the amount of area you will have to refinish.

When you are satisfied with the results smooth out the sanded area with 220 grit sandpaper and finish it out using 320 grit. You can now apply a finish to the neck. Be sure to check out the Vintage Amber Neck Stain available from Stagefright Music. Apply it before finishing the neck to give it that cool aged look.