1970s Kettler (Tree Frog) F-Style Mandolin

This is a "friend of a friend's" mandolin. My buddy Tim brought this in to fix-up for his friend who bought it in the '70s at a bluegrass festival of some sort. The owner long-forgot the maker's name but a little sleuthing by my friend Reese revealed that it was in fact made by Mr. Everett Kettler (who's still building gorgeous F-style instruments) when he was using the Tree Frog name in his early mandolin-building career.

It's a well-loved instrument and has had a number of things "patched-up" over time. The headstock got a nasty break at some point but it was repaired with some added "bars" for strength. Unfortunately, that meant the headstock's back-angle was too shallow. In addition, the neckblock must not be big enough to take the tension of the instrument as it was having "neck crush" issues where, under tension, the joint would "roll into" the top and cause the action to get too high. It also needed all the usual other stuff -- a level/dress of the frets and good setup-side work and a few hairline cracks repaired.

I had Tim learn how to do that all on his own (save adjusting the nut slots) and we solved the back-angle problem at the headstock with string trees. It's not ideal but it works! The neck-crush issue was the more interesting problem and for that I used a trick I do with hollowbody electric guitars that get the same problem -- I drilled-out a 1/2" hole at the endblock (under the tailpiece) and mounted a 1/2" poplar dowel that runs through the center of the instrument and connects endblock to neckblock. It's pinned on the endblock side with a 1/4" dowel coming down through the top of the block and hidden under the tailpiece as well.

This makes a very sturdy repair that transforms an otherwise-frustrating instrument into a solid, stable, daily driver. Also, despite what one might think, adding a rod between the blocks does not hurt sound at all. I've done it enough now to know that what it actually does is improve sound for most instruments as there's very little compression stress on the top of the instrument and so it can vibrate more freely.

Anyhow, it's nice to see a Vermont-made instrument back in action again and, as Tim's reported, its owner is falling back in love with it. It sounds tremendous and plays spot-on, so I can see why!