A Note For Beginning Guitarists
I often wonder, if every guitar purchased was properly set up, how many more guitarists there would be, and how many fewer guitars would be hanging in pawn shops. Getting beyond the initial soreness of the fingertips on the fretting hand is most likely the number one cause of attrition among beginners and 100% preventable.
Guitars come in all shapes, sizes, styles, materials and construction techniques. This is great and lends to the lure and romanticism we have for our instruments. The crux of this biscuit however is that if the thing isn’t playable, then it becomes a wall hanger or firewood. Unless your able to wrestle the music from a hard to play guitar.
The key elements are; the Fretboard/Neck, Frets, Nut and saddle. The key measurements are; individual string height at the first fret and twelfth fret, and neck relief and intonation. The techniques used and measurements desired can be found online and I will include some links as well.
Once your guitar is strung and tuned we will begin by measuring the neck relief. Have the guitar vertical to the bench, (gravity), and depress the sixth string at the first and fourteenth frets, (use a capo at first fret). Check the height at the seventh fret and record it. (writing down these measurements will aid in understanding the process and intent). The neck relief measurement should be .008” to .012”, if less than .008” a truss rod adjustment could be necessary, especially if you hear string rattle, (depending on playing style), if over .012” a truss rod adjustment would be necessary for lower action. To adjust turn (normally), clockwise to tighten which will flatten the upbow in the neck and reduce your measurement. I’ve seen this done with the strings tuned vs. loosened. Safer to de-tune, relieving tension, turn the truss rod a quarter turn or so then re-tune and re-measure. Do this gently and in small increments and recheck until you get the correct measurement. I recommend you recheck the neck relief in at around two weeks, after the guitar has settled in from the adjustment. Now check string height of each string at the first fret using a feeler gauge set of your choice. ( a note on feeler gauge: a longer angled blade works well for me. Short blade gauges make it difficult to reach center strings. I’d stay away from gimmick tools made for this. A feeler gauge is best.) When making initial measurements write them down. I have the guitar flat for the first fret measurements and the hold it vertical again to check the height at the twelfth fret.
We set the distance between the bottom of the string and the top of the first fret. These measurements will vary between types of guitars, electric vs. acoustic vs. classical, bass, etc. and personal opinion. On acoustics I aim for .024” on strings 5&6, .018” on strings 4&5, .011” on strings 1&2. If your measurement is higher than your target you will have to remove material from the nut slot in order to lower the string. This is normally done with a fret slotting file, or you can improvise one edge of the appropriate thickness of feeler gauge blade. Do this by filing ‘teeth’ in the edge of the feeler blade. It is certainly ok to stack the feeler gauges to get the desired thickness for measuring. As for the actually cutting I would recommend slotting files. Buy the ones you need. The slot should be wide enough to let the string lay on the bottom and move back and forth freely. Once your are removing material from the slot let the fear sink in. The fear of going too deep.. then you’re screwed. Seriously, I am always very cautious, using just 2 to 4 strokes of cut before resetting the string, bringing it up to pitch and measuring only to have to loosen it, remove it from the slot, and file 2 to 4 more strokes. This is very tedious work and should be approached with calm reserve. I can assure you that one does not want to ruin a nut and have to start over. Measure, loosen string and move aside, cut the slot, replace the string, tune the string, measure, repeat, repeat, repeat. If you are making a new nut, compare your measurements each time and count the strokes of your file to learn how much you are cutting. Do this consistently for better results.
Congratulations, you’re string heights at the first fret are correct and it’s time for the easy part. Adjusting the string height at the twelfth fret. On acoustics you will generally have to loosen all strings enough to remove the saddle and remove material from the bottom to ‘lower it’ . On electrics there are a variety of bridge/saddle styles, but generally the adjustment is simply turning a screw or screws. The target measurement here can vary also and can be more of a ‘feel’ adjustment than a hard number. Either way if your first fret heights are correct the next step is to re-measure the string heights at the twelfth fret. Now subtract your twelfth fret target from your current measurement. Double this number. The answer is the amount of material you will need to remove from the bottom of your saddle or lower the saddle(s) on an electric. Yes! It’s geometry. Since twelfth fret is the center point between the nut and the saddle that’s where we measure. Therefore, in order to lower the string 0.010” at the twelfth fret, requires lowering the saddle height 0.020”. The target height I start with here is .093″ E string 6th, .078″ at E string 1st, on acoustics. My personal set up is .080 at sixth string and .068 first string. Depending on the integrity of the fretboard, neck relief and playing style lower numbers can be achieved without buzzing. Striving for this magic lowest action is easily done on an electric guitar because if you get the saddle too low, simply raise the saddle back up. On an acoustic if you go too far it’s not that simple. The saddle of an acoustic flat top guitar should be flat on the bottom and have an arc on the top which matches that of the fret board. Most archtop acoustic guitars have a thumbscrew adjustment similar to electric guitars. On acoustic saddles you can always put a ‘hard’ shim beneath the saddle to raise it up. Apply super glue to the bottom of the short saddle and firmly place it onto a rectangular piece of shim material about a 1/16 “ wider and longer than the saddle. When it dries trim the excess. Assuming you’re .010” to low, use a .020 to ,030 thick shim and remove the material from the bottom for proper height.