How to Use the Simple CenterLine Finder

Thanks for your interest in our most popular jig! Below are the instructions that explain how to use this product. Please let us know if you have any questions regarding this jig.


Step 1

This jig comes pre-assembled and looks like this when taken out of the box(minus the packing material!)

Step 2

Place on instrument neck as shown making sure the dowels are in the complete open position. You can do this by pushing the knob towards the nylon nut until the dowels are in the open position. You may need to loosen the black knob first.

Step 3

Squeeze the two plastic dowels together until they touch the side of the neck. Do not press too hard.

Step 4

While holding the dowels against the neck, lightly tighten the black knob. DO NOT OVER TIGHTEN, as these nylon screws can be stripped. Now repeat these steps for the upper arm.


Now you can see the centerline as it extends from the peghead end of the instrument all the way to the tail end of the instrument. You can adjust the neck until the centerline of the neck matches the centerline of the body.

To use the Bridge Squaring Attachment, just place it on underneath the centerline base in a predetermined place(you will need to mark your scale length, then adjust for the front of you bridge).(NOTE: This picture shows the bridge attachment without the use of rubber bands. This particular one was fit exactly to the jig so it could be snapped on. This is currently not available, instead you will need to use rubber bands to hold this jig on) Then you will need to butt the nut end of the centerline finder against a dummy nut, then tighten the plastic dowels against the neck and tighten the knobs. Now all you need to do is to mark the centerline on the bridge and slide it under the centerline finder until it makes contact with the Bridge Squaring Attachment. Line up the bridge centerline with the CenterLine Finder's centerline, and the bridge is now located. Just tape it down, and prepare for gluing.

Sample Testing the CenterLine Finder

Testing of this jig was done with the help of Michael Bashkin of Bashkin Guitars ( A guitar neck was ready to be fitted to the body. It was tested against his manual method of locating the centerline and the bridge. Below are pictures and explanations of the testing:

1. We placed the Simple CenterLine Finder on the guitar neck.

2. We made sure it was butted up against a dummy nut.

3. Here you can see that the neck was off by about 1/8". Now he will need to verify that the CenterLine Finder will match his manual method.

4. Here are some shots of checking the neck alignment with the bridge manually. Found out that the Simple CenterLine Finder was 100% correct:

5. Now to correct this. Here are some shots of removing the neck and using the sandpaper method to remove a tiny amount of wood from the cheek.

6. Success at last! This whole process took about 10 minutes.