Ready to take your guitar building to the next level? This Instructable will show you how easy installing frets into a guitar neck is. I will use only normal shop tools that everyone has. The neck I’m working with I built myself and has a flat fretboard. I recommend starting with a flat neck for your first fret job because a radiused neck adds some extra skills and finesse that you can work on after getting the basics nailed down!
The only special items needed for this job is the fretwire itself. Everything else is probably on hand.

Supplies

Fretwire
End cutting pliers
Rubber mallet
Thin Kerf saw (really thin! Like .023” or)
Exacto knife
Pencil
Ruler or tape measure
Square
Flat file
Sandpaper

Step 1: This Is a Video Detailing the Steps Described in This Instructable

Step 2: Laying Out the Fret Lines

At the headstock end, your “zero” mark will be right where the Nut will go, usually where the downward angle begins from the neck. (Pic#2)
This will be a 25.62” scale length fret job. Meaning the distance between the nut (zero) and the middle of the bridge saddle will be 25.62”. (Pic#1)
So we have to have the frets in very specific positions along the neck for the notes to intonate properly as we play them up and down the neck.
There’s a complicated formula to figure this out but we have the internet so all these values are posted everywhere!
Make a sharp line across the zero position (where the neck angle breaks to the headstock). Lay your ruler on the neck with “O” on the line then start making a mark for each fret position until you reach where you want the frets to end.
Now use a square or straight edge to extend the lines across the whole neck.
If your like me you already shaped the sides of the neck before lining for frets so a square really doesn’t help make the lines straight (whoops)! Don’t worry if you have to sort of eyeball the lines. Unless the they’re really way crooked you won’t notice any intonation problems.

Step 3: Cutting the Slots

Ok time to get serious! Now we cut the slots into the neck you just spent so much time making. First I scribe the pencil lines I just made with a blade so the saw has something to follow that’s accurate and straight. The fret wire will cover some sloppy slotting but try to cut the slots evenly and consistent depth. I start at the body end of the neck so by the time I’m down near the nut I’m in the groove and slotting really well. Because in the end most playing is done on the bottom 7-9 frets for most people and you want these frets to be perfect!
When using the saw use a piece of tape on the teeth or something to show you where to stop for the correct depth of the cut. Take a piece of the fretwire and set it into your slot to gauge the depth and width. It’s ok to go too deep as long as you aren’t too wide. The tangs grip the neck from the sides, it’s not the bottom of the fret that holds it in the neck. A good idea is to experiment on a scrap of the same kind of wood you used for the neck. After slotting 10-12 slots you’ll know what to do and what’s working.
If the slot ends up too wide or deep don’t worry! A dab of superglue when fretting will fix that. Some people glue every fret anyway.

Step 4: Installing the Frets

Whew! Now the easier part. Not as much pressure! Take a piece of fretwire and press into the slot closest to the guitar body leaving about 1/8” overhanging the neck. Trim the other side off using the end cutters leaving again 1/8”. Finger press the fret into the slot tang first.
Now using the rubber mallet, gently but deliberately hit the fret in starting on one edge and working to the other side. Three or four whacks is good. If the fret is sitting proud of the neck after this you might have to deepen your slot slightly. The fret will not “bite” or burrow into wood very easily instead it will probably deform. After hitting a few frets in you’ll get a feel of how hard or soft to go. Make sure the neck is fully supported at this stage too because all this hitting can separate glue joints (like at the headstock)! The video in this Instructable has a demonstration of using the mallet.

Step 5: Filing the Frets

This Instructable isn’t going to show how to level and crown/polish the frets after installation. That’s a whole other Instructable! However when your done filing and sanding the frets the neck is playable.
Using the flatfile perpendicularly to the neck, grind each frets overhanging bit with downward pressure only. Pulling up will pop the fret out of its slot. Although the fret can be retapped in, it will never sit as tightly as the first time. Once the fret is filed down almost flush with the neck be careful! Gouging the neck at this stage is easy to do and any marks must be sanded out. Refer to the video for a demo of this step. I didn’t take many pics while I was filing.
When all the frets have been filed down to flush with the neck or pretty close, I turn the file and run it back and forth lengthwise along the frets and try to file the ends down so they’re right flush with the neck. Also a bevel of 30-40 degrees should be filed into the outside edge of the fret. It looks good and is smoother to the touch. This bevel can be worked in at this point.
Once the main shaping and working of the frets is done with the file, it’s time to sand out any marks or dings that may have occurred. I like to use sandpaper attached to a soft pad that I can run over the frets too. The fret ends can be worked with sandpaper so any very small snags can be sanded out. Anything too big will require another pass with the file. What’s important is working the fret ends so they are rounded and smooth so it’s comfortable to touch them when playing. If you run a tissue down the neck over the frets you will see immediately where it catches and rips. These spots require attention and more sanding/smoothing. Look closely at the frets and work out any rough spots even little ones. You might as well do it now before final sanding or prepping of the neck and definitely before putting a finish on!
Thanks for viewing my Instructable and I hope it was helpful!