Nut shelf not "square"

[el8ed]

Hello honored mentors!
On a Brown Bass that I just acquired the "nut shelf" is not at a right angle with the end of the fretboard. I don’t know if I am using the right term, but what I mean is that there is an angled gap between the bottom of the nut and the wood of the peg head that it is supposed to rest on. The “nut shelf” is angled back like the peg head. There was some wood glued to the underside of the existing brass nut which came off with the nut when I removed it for lowering the string height to fit the de-fretted fingerboard. The nut was glued to the end of the fingerboard.
I checked if the nut bottom was square and it seems to be so. A brand new brass nut blank shows the same angled gap as the nut that is installed right now when I hold it in place.
So my question is, do I need to apply some remedy to give the nut a solid space to rest on, like a shim or something? Do I just glue the nut to the fingerboard and leave well enough alone? Do I need a new nut?
Right now the nut is just held in place by the strings and the bass behaves as one would expect a fretless Alembic short-scale bass to behave—it sounds and plays gorgeous.
Having any aspect of the bass in questionable repair drives me nuts though. 
Thank you for suggestions and advise!

[lbpesq]

Some pics might help.

Bill, tgo

[el8ed]

Thanks Bill, you are indeed right. Hard to photograph but see attached.
I had another look right now in order to take pictures and it turns out the the "nut shelf” seems to be correctly straight after all, just the fretboard itself is not quite square at the end. Maybe that was done at the fretless conversion some years ago or some other “accident" in it’s 18 years of life.
From what I am seeing now I might just glue the brass nut to the peg head and live with the slight gap to the end of the fretboard. Yeah—nay?

[lbpesq]

If you move the nut so it butts up flush against the fretboard, is there a gap on the bottom of the nut?   I guess I’m asking if the angle of the end of the board where it hits the headstock greater than 90 degrees?   If so, I would figure out which position results in the intonation being closer to the fret lines.   If it’s like in the pic, I’d just leave it alone.   If the intonation is closer with the nut up against the board, and that created a gap at the bottom, I would craft a wooden shim to fill the gap.   Or I would get a brass blank and fashion a custom fitting nut.  I hope this makes sense.   FWIW, the nut on my ‘76 Series guitar sits flush with the board end.   

And, of course, I’d wait for some more advice, especially if Mica chimes in, before making any final decisions.

Bill, tgo

[el8ed]

Yes, the angle of the finger board where it meets the headstock is greater than 90 degrees, hence the gap.
Thank you, Bill!

[edwardofhuncote]

I would have thought that bass came with an adjustable nut. Maybe it was discarded when the bass was defretted... wouldn't adjust low enough anymore, didn't want to file the slots... hard to say. I suspect some of what is going on with the poor fit is underneath that nut. There should have been a thin brass plate fixed there for the nut to adjust upon. Moot point... just doing some CSI, the bottom line is you need a perfectly flat surface for the nut to sit on.



There are a couple options here. Any competent luthier (even a part-time shade-tree repair guy like me) could straighten this out in less than an hour.


1.) Shim this one with a thin veneer of wood and get the angle/fit right.


2.) Make a whole new nut. Brass is traditional Alembic, ebony is very nice on a fretless. (I have one Alembic with bone too)


Making a new nut isn't easy, but not difficult either. If you haven't made one before, you might be better served to farm the job out. The shim option is pretty simple, and could be done on a good, flat kitchen counter with several grits of sandpaper and patience.


Congratulations on a nice bass, Good Luck. I have a soft spot for Brown Basses.

[el8ed]

Thank you Greg for your thoughts.
The wood underneath the nut is actually flat and I presume has the correct angle—looks like factory fresh. The end of the fretboard is another matter altogether. I tried to take a photo without the nut to illustrate.
I will put on the strings with the nut flat on the surface and snug with the fretboard end and figure out intonation. If I can set it correctly I guess I might just leave it like that.
I  am also contemplating having a new nut fitted and was thinking either ebony of Tusq to complement the fretless tone.
Any thoughts and ideas are much appreciated.

[edwardofhuncote]

It looks like some of the epoxy coating made its way to the end of the fingerboard. You should be able to file it back to the ebony. Just stop when you get there. Don't file any wood. Might be all you need to do.


Tusq is nice. I have used it on a couple guitars. I use ebony for string-nuts on upright basses. I play very few open strings on bass guitars, but I personally can't tell a huge difference between the brass, and bone, and ebony. The point of a nut is that it be a hard substance that resists wear and provides a good witness point for each string. I love the detailed adjustment in a brass nut from Alembic, and wouldn't have mine done any other way, but that said I have adjusted each of them ONCE. (the lucky soul who gains custody of them next will appreciate having the option as much as I did)

[el8ed]

Yes, of course, now that you say it I can see it as well. Thank you so much Greg!
I think I should be able to manage removing the excess epoxy to get everything square again.
Thanks also for your impression of the tone differences, or lack thereof, in nut materials—very helpful.

One more question if you don’t mind: What do I glue the nut to, the peg head or the fingerboard?
Thanks again!
Cheers, Oliver

[rv_bass]

Others correct me if I’m wrong, but I think gluing it to the peg head with a little crazy glue will allow you to break it free with a little tap if needed at some point in the future.

Also, you don’t necessarily have to glue it in place if you don’t want to, the string tension should hold it in place once tightened.

[lbpesq]

Rob’s correct, you want to insure it will be easy to remove it in the future.   As for nut material, I usually make them out of bone on most of my builds.   I bought a bunch of really old blanks from an older luthier who was liquidating a bunch of stuff.  One advantage of a brass nut is that open strings will sound more similar to fretted strings.   Of course, that’s not an issue on a fretless.   What year is your bass?  The earlier ones didn’t have the adjustable nut.   Neither my ‘76 guitar, nor my ‘77 12 string guitar have one.

Bill, tgo

[el8ed]

My bass is a 2003 but came to me with a non-adjustable nut that was a bit too high for the fretless configuration. I got the nut lowered and the strings are now just above the fretboard—might have to go a little lower with the E string still. I take it a little at a time with plenty of testing in-between. I’m in no hurry really, since I am a bloody novice with the fretless. 

[el8ed]

I did as suggested and carefully filed away the excess epoxy at the end of the fingerboard. I got a little skittish when there was only a very thin layer left. I thought it was time to leave well enough alone. There is only the tiniest gap left—or maybe I am just imagining it—see photos The nut sits securely on its bed now and does not move even though it is not glued on yet. I am happy with it, the intonation is correct. The first position is easy to play with low string height. The bass sounds awesome. Now all that’s left is to install brand new strings as soon as they arrive from the mothership and start learning to play fretless correctly. 
Thanks guys for all the help, advise and hand-holding. I could not have done it without y’all.

[lbpesq]

Lookin’ good. All’s well that ends well!

Bill, tgo

[mica]

Looks great! And as a bonus I can now see how the edge of the epoxy was handled on the fingerboard - is that edge sharp?