Little Things

Miriam Webster defines "kerf" as the width of cut made by a saw or cutting torch. What does that have to do with guitar building? It seems that all acoustic guitars have an important component called a kerfing strip. If you look inside an acoustic guitar you will see the kerfing strip running along the perimeter where the top and bottom are attached to the sides. The strip is just a length of wood with a series of perpendicular cuts that only cut through about 90% of the thickness. The end result is a flexible, continuous piece of wood. The kerfing strips are glued to the tops and bottoms of the guitar sides and they become the surface to which the guitar top (soundboard) and back are glued to. I'm calling this post "Little Things" because kerfing strips are an unseen yet critical component of an acoustic guitar, and something that I, and probably you, have never thought about before this project.

Kerfing strips are available for purchase at luthier supply houses but I saw enough pictures to convince myself that I could make my own. After all, I do own the cheapest state of the art table saw that Home Depot had to offer. Standard kerfing strips are installed with the solid edge glued to the guitar side and the slotted edge visible from the inside. I decided to reverse that because Michael Obrien of Obrien Guitars said that would be cool in one of his nifty luthier instructional videos on youtube. It probably makes no difference. I did make a mistake here that caused some concern. I really should have glued both sides together with the end blocks before installing the kerfing. Instead I installed the kerfing on each side before the sides were together. Little did I know that the kerfing would pull some of the curve back out of the sides, and add strength as well. Now I have two sides that don't quite fit and they don't bend as easily as before. While I was gently persuading the sides back into the shaping form I heard the dreaded "craaack!" of wood breaking. A cool sound at the ballpark...not so much during a woodworking project. A small crack appeared on one of the sides. Remember in my last post I said that tailgate guitar would have a lot of character, this is one of the reasons why. I have since repaired the crack and hopefully I'll be the only person who can find the flaw.

Up until now I've been making guitar parts. With the kerfing installed I can begin assembly. It's very encouraging to see tailgate guitar taking shape.

setting the depth of the cut  

 

 

you can just see the miter gauge on the left

which keeps the wood at a 90 degree angle to the blade.

 

 

 

 

 

It takes a lot of clamps to make sure there are no gaps

 

 

 

 

End blocks and top kerfing are done and ready

to accept the top of the guitar.