Locking Nut Routing Depth

[daveq]

Can someone please verify my calculations here? I did a search on locking nuts and turned up 6 pages of information but none of them came out and said "this is what the depth of the route should be".

One disclaimer before I get into it though - not all locking nuts are made to the same specs. The Schaller made nuts do seem to match with the folllowing info but the replacement nuts from stewmac don't seem to match up well. So, check the locking nut height before assuming any of these calculations will apply:

The question is how thick of a shelf should be left for a locking nut.

R1,R2,R6,R7,R8,R9 nut height = 0.225"

R3,R4,R5 nut height = 0.275"

Floyd Rose recommends that the shelf depth be 0.215" (0.265" for R3,4,5) from the top of the frets.

So, to figure out how much wood to leave under the nut, take the total height of the fretboard and the fret crown and subtract 0.215" from it (0.265" for R3,4,5).

For example,

R2 nut

0.25" fretboard

0.046" crown frets (stewmac #149) - assuming minimal leveling

thickness of shelf = 0.25" + 0.046" - 0.215"

= 0.081" (2.05mm) or just over 5/64".

That seems a bit large to me but maybe not? Can anyone verify this?

[Scott Rosenberger]

I don't measure for routing. I just route the excess wood away to the bottom of the nut slot that is already there. then I string the guitar and measure the action At the first fret, remove the nut and route away a little at a time until the action is where I want it. This way you don't over route and have to use shims

[daveq]

Scott - what do you use for a guide when routing that area so that you don't end up going past the 0 fret position?

When I do mine, I have a jig that I clamp the fretboard into. It works very well but would not work (without modifications) if it were glued onto the neck.

Do you see anything wrong in the calculations? I wonder what they assume you want for clearance at the first fret? I guess I could do some more calculations to figure that one out.

I've been routing down to about 1mm for most of mine. One of them (my first) ended up a bit too deep but the others are fine. This is just the first time I've seen actual calculations/instructions so I'm trying to make some sense out of them.

Thanks for the reply.

Dave

[Scott Rosenberger]

I just use a straight board at the slot and use a bearing bit