Acoustic Guitar Construction

The truss rod slot in my kit-guitar's neck (not one of Ken's) is shallow by roughly 1/32". I need to clean it out by at least that much material so the truss rod doesn't try to hold the fretboard off the neck. I found an Amana 'dado clean out router bit', which has a ball bearing that could guide the cutter so as to not inadvertently widen the slot (router bit is 3/8" in diameter, the slot is 7/16" wide), to deepen the slot, running it up one side and down the other. If there's an alternate idea that doesn't involve a router I'd love to get enlightened. I have great respect for Porter-Cable's ability to overdo the widening thing if I don't have some kind of guide. According to the Amana's dimensions, I'll have 1/16" of the bearing riding on the slot edge as I massage the slot bottom.

Thanks, folks. Very much.

I usually use a chisel to deepen the slot. I use it as a scraper, holding the chisel upright and pulling it down the slot. If it was very shallow I might take it back to my router table and deepen it with a 3/8" bit.

Appreciate the advice. I'll see if I can make peace with the slot with a chisel. I am reluctant to use a router bit which can widen the slot without the constriction of a bearing. I don't trust myself running a neck down a router table without overdoing the widening. Neck's irregular shape means I won't have fence support. The slot fits the truss rod width so nicely, I don't want to compromise that.

Ditto John P --- plus if the slot is uneven or too deep, you can make a dummy truss rod the out of wood cover it with clear packaging tape. Lay a little Bondo in the bottom of the slot then clamp the dummy rod in place. Once dry the Bondo will not stick to the dummy rod. I've done this to make a curved slot for the old "Gibson" style 3/16" rods with threaded end and stop, pre-compressing them with a bit of curvature adds to their effectiveness.

Thanks, Ken. I hadn't considered levelling an irregular slot with Bondo. That would sure make for a good fit. Much obliged.

Learn something every day. Ten minutes with a chisel impersonating a scraper and problem seriously fixed. Had to use a Dremel cutter to level the end grain of the dowel running up the heel, and all done. Turned into a non-event. Thanks to all. Seems so simple in hindsight.