Radius nut

[Amandalyn]

I'm putting a new bone nut on my mandolin, I need to radius the top to match the fretboard, and am not sure of the best way to do this. I have the old nut to use as a guide if needed. Thanks in advance.

[Paul Hostetter]

The frets follow the board and the nut slots follow the frets. Install the blank, rough out the top surface, do the slots until they're perfect, then remove what remains above the halfway point of the strings.

[Antlurz]

One way is to file or sand off one side of a very sharp pencil until you get the height you need, then just run it along the nut, while resting it on the frets. It will follow the curvature perfectly.

Ron

[Bill Snyder]

Pauls way makes sence to me. Set the depth of the slots before you take too much off the top, although you can use Ron's method to mark it a bit high for the rough in stage.

[Paul Hostetter]

Given a choice of one or the other, I see no point in the pencil thing at all. If you think you can cut fret slots, you should certainly be able to rough in a nut by eye, whether it's flat or radiused.

[Antlurz]

True, but the pencil line gives a bit of security for someone who doesn't have your many years of experience...

Ron

[Antlurz]

I want to apologize for making the ellipses backwards on the drawing of the sharpened pencil.

I don't, however, think they should alter the point trying to be made.

Ron

[bryce]

There is nothing wrong with marking it first with a pencil. I have done this.I rough in my bone nut on the belt sander, then after its glued in I finish it with files and fine sanding. Fit the nut in the slot snug. Then mark a line. remove the nut and remove the bulk of the extra bone,(off the top and the sides) then glue it in and fit to the sides of the neck and then file your string slots. Then finish the top down to the height you want at the strings,(not below half the string diameter). Bryce

[bryce]

Oh yea, If its replacing a nut in a finished instrument I finish the sides to the neck before I glue the nut. Bryce

[ronlane3]

I'm not a luthier, but couldn't you just remove the original nut and trace it as an outline on the new one?

[MandoDiddle]

Ron,
As a novice I really like the pencil method you showed. I have used this technique 3-4 times now and it gives a certain amount of security for us newbies.

Bill

[Frank Ford]

Noobie, schmoobie, I use the half pencil method all the time:

http://www.frets.com/FRETSPa....t1.html

[Chris Baird]

I use the half pencil as well. I've never understood why someone would go filing through a bunch of bone. I mark with the pencil then take the nut to the disc sander, I tilt the sander such that the angle of the top of the nut is right then sand down till I have just enough bone above my line. When I go to file the slots I only have to go the depth of the string or a 1/3 of it. In Don MacRostie's video he literally files through 1/8" or more of bone to get his slots down. That just doesn't make sense to me.

[Amandalyn]

Thank you all for your advice. I used the half pencil and have been working away slowly at this. It's my first, I'll let you know how it turns out.