MULTI-RADIUS/COMPOUND RADIUS FRETBOARDS {original article}

"Multi-radius fretboard" or more commonly known today as "Compound Radius" what does that mean? It's not as esoteric as it sounds. A multi-radius fretboard is simply one that has more than one radius along its length. Picture a section cut out of a cone shape. The advantage is that such fingerboards give a guitarist great mobility for string bending and yet retain a comfortable feel for chording.

In 1978 I created this idea while refretting a Fender Stratocaster. I owe some credit to the owner, who told me, "I want my Strat to play the same as my (Gibson) Les Paul does." In other words, he liked the lower string action on his Les Paul, and wanted to transfer that to the Strat. The request didn't seem to present a problem. I refretted the guitar and proceeded to final setup.

With the strings set very low, same as Les Paul, the Strat played great-that is until I tried to bend a note. The note died immediately because there wasn't enough clearance down the fingerboard to allow the string to vibrate. I realized the Gibson had a 12" radius while the Fender had a 7.25" radius. I had always liked the smaller-radius fretboards' feel for chording. Instead of just making the entire fingerboard flatter (larger radius) I tried to retain as much of the small radius as possible and honed down the frets gradually up the fingerboard toward the 21st fret. I found that the radius could be gradually changed along the fretboard length, giving the player the best of both worlds.

Once I had proved this by reshaping the frets, I went ahead and pulled the frets and reshaped the fretboard and refretted the Strat again. Over time, I found that my optimum conical radius combination was 10" at the nut graduating to 15" radius at the 21st fret. You can achieve this by hand planing, using several templates to measure the radius at different points along the fingerboard. Because these fretboards are standard with the guitars I build, I've made a special trapeze-type fixture for my fingerboard shaping machine. It allows me to swing a fretboard blank through the correct arc to achieve the perfect multi-radius graduation.

COMMENTARY {by Denny Rauen about inventing Multi-Radius fretboards}

While doing a little research I came across a few blogs discussing my creation and realized that others will read these various undocumented and misleading comments about conical fingerboards. I feel a need to give a few words on my behalf as the generalizations about my conical fingerboard are overwhelming. As stated earlier my idea was originally published in American Lutherie and String Instrument Craftsman. For those interested in historical proof the following few paragraphs will help with the timeline and how my idea clearly went viral after I published it for all to use in the mid 1980's.

Fact, the "Multi-Radius Fretboard" (conical fretboard) was the result of my hard work and guitar players need for bending notes with a very light action while avoiding choking out. No more compliclicated than that and I still remember creating this fretboard like it was yesterday. Prior to publishing "Multi-Radius Fretboard" there was no literature I had seen explaining that a guitar maker, violin maker or string instrument craftsman of any kind used a conical shaped fingerboard or that they had created one for any specific purpose let alone for the purpose of bending notes. If there were fingerboards made to alleviate this problem 200 years ago or even in 1977 I was not aware of this nor am I aware of it to this day.