david farmer wrote:
Freeman, maybe you could cut and paste your post about methods here. I think it's interesting and helpful.
I divide the analysis into two steps - the overall condition of the instrument and the specific measurements that go into doing the setup. Obviously if there is some other fundamental reason the guitar has been brought to me (detached bridge, broken headstock, gun shot hole in the side) that needs to get dealt with before the setup. On a Fender I check that the neck screws are tight.
The condition part starts with a general overall look at the instrument - are there any obvious cracks, is the bridge loose, any obvious structural issues. The second thing I look at is the hydration condition of the instrument - are the fret ends sticking out, is the top sunken, is the finish wonky. I always feel better if I see some sort of hydration system in the case, I always feel bad if I hear the guitar is kept on on a stand. If a guitar is dry I will do one of two things - a very quick setup, usually just shimming the saddle - and I give the owner one of my industrial strength humidifiers (a car wash sponge in a big baggie with lots of holes in it) to put inside the guitar. I tell them to come back in a month and we'll check again.
Next I check the neck angle - on an acoustic its the old straight edge on the fretboard pointing to the bridge trick - might be something a little different on an archtop or an electric. Basically what I want to know is does the geometry permit me to do the setup? On an electric that boils down to having enough travel in the bridge/saddles to get the action I want plus having a little travel in reserve. On an acoustic I want to know if I can lower the saddle enough to get the action I want. An over set neck can be an indicator of a dry guitar - I factor that into the hydration question. If the neck angle is bad enough that I can't get the kind of action I want we discuss the options - reset, shimming a Fender, whatever it takes.
Assuming the guitar is structurally sound, hydrated and has an acceptable neck angle, I then check the frets. Basically two things - are there grooves in the frets and how bad are they, and second are the frets level. The groove question is a judgement call, how bad do they look. The primary way I check for level is the "next fret clearance" thing that I described in the other thread - I hold a string down at the first fret and find a thin feeler that will just fit under at the second - its usually 2 or 3 or 4 thousands. I then just move up the fretboard, holding down the string at each fret and checking the next one. I'm not really measuring the gap, I just want to see if the feeler will fit. If it gets tight at one fret then I mark that fret as possibly high (and come back with my fret rocker). If the clearance seems to get progressively looser that is all right - usually means the action is way too high. If it gets at one fret then that fret is probably low (pretty uncommon). If the gap becomes smaller as I go up the board I might have a high fret or too much relief or something funky at the neck heel. I'll note on my little spread sheet what I'm observing and usually do a little rocking to try to nail it down.
Based on the next fret clearance and a fret rocker I can tell the owner that the frets are good, or that one or more is high, or maybe that some or all need to be replaced. If we are talking about replacing frets then I also look at whether this is time to sand divots out of the board. But once again, if the frets aren't perfect the setup will be compromised.
All of that took much longer to type out than it does to check it and I'm happy to do it with the owner watching. It doesn't bother me a bit to say "I won't do a setup until we've fixed XXX". It doesn't bother me if they decide to take it somewhere else. I'll give them an estimate of what the reset or fret job will cost, or how long it will take to rehydrate.
OK - assuming it passed all of those structural tests, now I start measuring and filling out my spread sheet. The guitar still has the string on - just measure and record everything just as all of us have been doing for a long time. I usually just measure the two outside stings unless something weird happens, however on my final check I do measure all the strings.
- Relief, capo at one, hold down a string at the body joint (12, 14, 16, 18...) and measure the gap half way between (5, 6, 7..). I measure the nut action at the first fret with feeler gauges, I measure the overall action at the 12th fret with that little StewMac action gauge. For right now only the E strings is necessary. I check the intonation with a chromatic tuner and write down how many cents sharp or flat each string is. Sometimes (electric guitars, archtops, 1970's Martins) I'll measure and write down the actual location of the saddle break point (I've got a trick I can describe if anyone is interested). I learned from a painful experience to measure the diameter of the two E strings with a caliper or micrometer - it will spoil your day to do a setup on a set of 11's and then find 13's in the case to be put on the guitar.
It has taken me all of five minutes to take those measurements and fill out my spreadsheet. I'll fill in the "target" boxes altho some of them I know by heart. Tune the instrument however its going to spend most of its time. Set the relief. Changing relief will change almost everything else so do it and leave it. Now I do whatever I'm going to do at the nut - if I lower the slots by a certain amount I know it will lower the 12th fret action by half that. I also know that when I lower the action it will have hardly no effect at the nut/first fret, so do the nut first. Do each slot at a time with tension on the other strings, measure each string. I like to see the 1st fret action rising slightly as I go from the 1st string across the nut - maybe something like 0.014, 0.014+, 0.016-, 0.016, 0.016+, 0.018. I don't have intermediate feeler gauges so I just extrapolate.
One little check at the nut is to hold down the string between frets 2 and 3 and check the "back fret clearance" at 1 - there should be just a hair (2 or 3 or 4 thousands again, or tap the string and listen for a "ping").
Now do the 12th fret action by raising/lowering saddle(s). Depending on the guitar and player there will be different target values but like the nut what I want to see is gradual increase from the high E to the low, maybe 0.060, 0.065. 0.070. 0.075. 0.080. 0.090. By the way, I take all measurement is decimal inches and extrapolate between marks on the SM gauge. I have a hard time remembering if 7/64 is bigger that 3/32 or 1/8,
Once the action is set I do the "next fret clearance" again on every string at every fret. I can promise you that if it plays clean on the first fret with 0.003 clearance at 2, as long as I have 0.003 at every fret it won't buzz. It doesn't bother me if the clearance increases as I go up the neck, it just tells me I don't have the lowest possible action. And on most acoustics it will increase from 14 on as the fretboard extension falls away.
Lastly I'll futz with the intonation. If its an acoustic I usually just do the generic B string compensated saddle but I still check it. If its an electric I do whatever it takes to get it right - I want to see 0 cents change when I fret at 12 (I have a jazz friend that asks for it to be set about 2 cents flat). I've left out pickups and tremolos - they are sort of special cases.
Pull the old string off, clean the fretboard with steel wool and everything else with a damp rag, put a new set up strings on it, fill out the last column in the spread sheet and give it back to the owner. Open the next case and start over again