Shaping a nut to fit a Fender radiused slot

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Issue 267 July 28, 2016

Most Fender nuts have a curve on the bottom, so shaping them for a perfect fit is tricky. It can be the toughest part of making a new nut. Erick Coleman shows you some troubles to avoid, and a neat trick for good results.

In this Trade Secrets video:
  • What not to do, and why.
  • Determining the radius of the fingerboard.
  • A sanding jig that's simple to make.

Video Transcription

[on-screen text reads: Stewart-MacDonald - Trade Secrets!]

Shaping a radiused nut

[on-screen text reads: Erick Coleman, Guitar Repairman]

Erick Coleman: The nut on this P-bass is toast. It's chipped all over and the slots are worn so low that the strings are buzzing on the first fret. So, we really need to change this guy out. And with Fender nuts, most of them have a curve on the bottom that matches the radius of the fingerboard. So, when you make a new nut, you have to take that into consideration. And while it's hard to see when you're looking at it, if you set a ruler in there [on-screen text reads: StewMac Shop Rule -], you can see that that rocks back and forth, it's not sitting flat in the slot.

Technique 1: Manually filing the nut in a vice

When making a Fender nut, sanding that radius into the bottom can be the most difficult part of the job [on-screen text reads: Nut and Saddle Vise -]. And the tricky thing about it is keeping the bottom of the nut square to the sides while you're filing [Erick has the nut locked into the Nut and Saddle Vise]. It's really easy to tip the file [on-screen text reads: Nut and Saddle Shaping Files -] one way or another and to make this ledge uneven and out of square.

Technique 2: Adhesive sandpaper on the fingerboard

Here's another technique I see a lot of people using. They'll put a piece of adhesive back sandpaper [on-screen text reads: 3M Stikit Sandpaper -] face up on a fingerboard, and then work the nut blank back and forth to try to stay on the radius in that way. And again, just like working with files, it's really easy to get the nut just skewed just a little bit in one direction, and that'll throw off the bottom in relation to the sides.

Technique 3: Using a beltsander

The same problem goes when using a belt sander too. Just a little rock in either direction will throw you off. If your nut doesn't fit the slot properly, you lose tone and sustain as a result of the bad coupling. Plus, it just looks kind of bad. I wouldn't feel comfortable passing this on to my client.

The preferred technique that I use in my shop

Let me show you what I've been doing in my shop. The first thing I do is determine the radius of the fingerboard [on-screen text reads: StewMac Radius Gauge -]. And in this case, it appears to be a traditional Fender seven and a quarter. And then I mark my radius out on my blank. So, what I have here is the small robo-sander [on-screen text reads: Robo-Sander Flush Trim Sander -] installed into my drill press. I have a scrap board with a hole drilled in it that is an inch and one quarter in diameter, and it's deep enough to clear the bearing of the robo-sander, leaving only the sandpaper grip part exposed.

So, my workboard here, on the backside I have two of our one inch guitar repair magnets installed [on-screen text reads: StewMac Guitar Repair Magnets -], and that helps keep the work table secured to my drill press table while I'm working. I made a little fixture here by drilling a hole in a piece of scrap wood. I have our vacuum attachment here [on-screen text reads: Micro Vacuum Hose Kit -], which goes into my shop vac. That's going to clear away most of the dust. And now I'm going to sand this radius into the blank here. I'm using the 80 grit sleeve because the finer grit cuts cleaner, but still leaves some teething for the glue to grip onto. I'm carefully and evenly removing material until I've reached my pencil mark. Checking it with my radius gauge. Looks pretty darn good. Fit this blank. Nice and tight. Feels good. I want to check it for gaps all the way around. Nothing on this side. Nice and tight. Nothing on that side. Looks really good with the hard part out of the way, it's all downhill from here.



Erick Coleman

StewMac Senior Technical Advisor

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