Tuesday, December 13, 2011

Scarf Jig

I decided a while ago to vary the manner with which I create head stocks for my guitars. 

So, I commenced to search for information about how to make a scarf joint, which is the design of most commercial acoustic guitar necks.  A scarf joint is the design which makes the headstock set at an angle to the neck.

There are any number of sites that make recommendations, and most of them suggest cutting the angle with a handsaw and doing the finish planing and fitting with hand tools. 

After studying the recommended process, I decided that creating a scarf joint didn't need to be such a cumbersome and labor intensive process, to say nothing about the production inconsistencies which can result. 

I built a simple jig to fit on the table of my power saw, and voila, there came a perfectly sawed and angled headstock.  And, I can easily vary the angle from 7-12 degrees, and the angle of the cut remains constant from neck to neck.

In the first photo, you will see the simplicity of the jig. 

The base is a piece of 1"x10" pine with a length of screen door moulding fitted to the bottom as a guide for the base to move accurately along the guide slot in the table of the saw.  A dowel handle is glued into the base for safe movement of the jig through the blade. 

The angle guide (protractor) pivots on another dowel at its leading end, and a small eye screw was tailored to act as a angle lock pin at the trailing end of the base.  All that is needed is to decide what degree of angle to cut the scarf joint; set the pin in the proper hole; insert the blank neck stock into the guide (second photo -- notice the small retainer piece near the leading edge of the angle guide, which holds the stock in place throughout the cutting); clamp the neck firmly in place and cut the angle. 

The position of the neck stock in the jig will determine where the cut is made, which in turn determines the final length of the headstock.

Once the cut is made, the neck and small severed piece is removed.  The small severed piece of stock is flipped 180 degrees and glued to the opposite side of the neck, forming the angled headstock desired.

It's that simple, quick, accurate and not very labor intensive, which all works for me.

When the glue sets (usually 12-24 hours depending on what glue is used)  other pieces can be added to complete the design; shaping of the headstock takes place; some type of veneer is added to the top to hide the scarf joint; and the neck is then finished and ready for installation.

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