Installing a Fender LSR roller nut

Whammy. Whang bar. Vibrato bridge. Wiggle stick. No matter what you call it, they are going to knock your guitar out of tune if it’s not set up properly. The main culprit for guitars going out of tune is the nut– strings catch and bind in there, and they don’t return to pitch. While a properly made nut cut from bone or brass will keep most people happy, sometimes you’ve just got to take it to the next level and install a Fender LSR roller nut. The roller nut is a pretty ingenious device – the strings glide across it on ball bearings, virtually eliminating all friction in this crucial area. Installing a LSR roller nut is fraught with great peril, and you can really screw things up if it’s not absolutely perfect. But since when have we ever shied away from terror?

Our friend Mark brought in his Squier Strat that he had been putting together during his time in quarantine. He added a Bigbsy vibrato, a roller bridge, and locking tuners, and was still having issues with it staying in tune. He asked us to do a PLEK fret level and setup, and to install a Fender LSR roller nut. Upon seeing the original plastic nut, we could see why he wanted an upgrade:

Apologies for the fuzzy photo – but even in focus the nut looks bad!

After we leveled the frets with our PLEK machine, I removed the nut first by tapping it gently to break the glue loose, and then pulled it up and out.

The Fender LSR nut is wider than most stock nuts, and won’t just drop in to the existing slot. Nut placement is absolutely critical – if it’s even slightly off the entire guitar will be out of tune. If the nut is place incorrectly, the guitar’s scale length changes, making every fret in the wrong place. This has to be done right.

Fender recommends that the leading edge of the existing nut slot be cut .094″(2.38mm) towards the first fret. I carefully measured this out with a micrometer and marked my line.

Measure thrice!

Here’s where things get tricky: I planned on cutting this slot with some custom programming with our PLEK machine. We have the capability of cutting nut slots with the PLEK, which it is designed to do based on the scale length of the neck. But this guitar needed the nut slot cut in a different place, so I was going to have to trick the PLEK into doing my bidding. I programmed the PLEK, telling it that the guitar was fretless, and used a dummy fret for it to reference as a nut locator. I placed the dummy fret onto the mark I had made, exactly .094″(2.38mm) forward from the existing nut slot. The PLEK would now see the dummy fret, and would think that the nut slot is further forward than it would be for this scale length, and would cut it exactly .094″(2.38mm) towards the first fret. Yes, I may have lied to the PLEK, but I don’t feel too bad about it. It’s a robot, and doesn’t have any feelings (yet!).

Dummy fret used to fool the PLEK.

Then I loaded the guitar into the PLEK, and programmed it to cut the nut slot to the LSR roller nut’s dimensions. The PLEK uses a 2mm bit, spinning at 50,000 rpm to cut the nut slot.

Very sharp – no touchy!

The PLEK cut this slot in under five minutes. It’s a clean cut, and perfectly placed.

Now it was time to install the LSR roller nut. I marked out the holes for the screws, and drilled pilot holes for the screws to sink into. We always drill pilot holes – this prevents the screws from breaking or stripping out and turning a 20 minute job into a 2 hour job.

It’s a perfect fit! I set Mark’s guitar up with a super low action, with LSR roller nut set so that the strings just barely pass over the first fret. Now Mark can put that whammy bar to work with no worries of his guitar going horribly out of tune. Awesome!

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