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Guitar Setup - Part 1

 
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randyc



Joined: 14 Sep 2006
Posts: 407
Location: Eureka, CA

PostPosted: Sun Oct 25, 2009 1:12 am    Post subject: Guitar Setup - Part 1 Reply with quote

Many, many articles have been written about this subject. I’ve read a great many of them and have yet to find one that is “wrong”. All will accomplish the desired results, so why am I going to add yet another one to the mix ? Because it doesn’t seem obvious to most people that there are two distinctly different problems in setting up a guitar and that solving the first problem is the key to solving the second one (achieving a satisfactory setup).

Most of what I’ve read doesn’t adequately quantify the measurement technique so that it is 100% repeatable (in fact it’s not even 50% repeatable for me within a reasonable length of time). We’re somewhat familiar with the basics, what the various adjustments do and how to make them. But even before one attempts to make adjustments one must be able to establish a standard of satisfactory performance (or compare against one) … maybe an example will illustrate my point better.

You’ve just changed your strings to a set that you suspect is exerting different (makes no difference whether more or less) tension on the neck of your guitar and you think that a new setup is in order. Or you think that the instrument doesn’t play as “easily” as it used to play. Or it fell off the stand, or any combination of these … How do you actually confirm that the instrument is playing as nicely as it used to play ?

It’s simple isn’t it ? One measures the clearance between the strings (usually first and sixth string) at an arbitrary known point (usually the twelfth fret). The helpful folks who talk about these things – even factory technicians – will generally give guidelines to assist you in determining what satisfactory clearance should be (it’s an individual thing). Clearance is usually given in terms of the distance between fret and strings, almost always expressed in units of 1/64 inch. If the measurements are the same as the last time you made them, the guitar has not changed.

Here are my problems with that technique:

*It’s difficult to make a measurement with readily available instruments, like a 6 inch machinists rule (e.g. individual vision quality, parallax error, reading and counting those tiny little tick marks).

*Can’t see small differences in measurements - 1/64 (approximately .016 inch) is actually a fairly significant amount, in my opinion, I can “feel” that difference easily with my left hand when playing, so can most players. (As a point of reference, experienced machinists routinely feel errors of .002 inch in the alignment of two surfaces using touch.)

*It takes an appreciable amount of time to make a measurement that is not very precise - that’s distasteful, at least to me.

Some have proposed incrementally improved techniques, like substituting feeler gauges for measurement scales. This has the possibility of improving accuracy but a lot of experience is required to develop a “feel” technique that assures repeatability – it doesn’t work for me very well at all.

More sophisticated ideas have been tried for obtaining accurate measurements while eliminating “operator error” from the process. One that I’ve admired is a special-purpose device consisting of a stand that supports the guitar neck firmly while holding a dial indicator, calibrated in .001 inch increments, rigidly above the strings. The indicator plunger is used to depress the string from normal position until it’s resting firmly on the fret. The string clearance is then read from the indicator. It’s accurate, too – I’d say at least five times more accurate than visually reading a scale.

(An electrical circuit is sometimes used with this method to assist in determining when the string is seated against the fret, an indicator light or buzzer is included in the circuit.

A big problem with this instrument is that this stuff is just unavailable to the average guitarist and it’s costly. Maybe the repair tech at the music store has one, but who wants to have to pay to have their action checked three or four times a year ?)

Another problem with this technique is that the plunger applies enough unintentional spring pressure to the strings to deflect them slightly, even when one is not applying intentional force to the plunger. This introduces error into the measurement that may be considerable, possibly as much as 30% and the amount of deflection is inconsistent between the first string and the sixth string. (To be fair, since the measurement only has to be relative, this isn’t a point of real concern.)

It’s All Too Complicated

What I wanted was a simple procedure, using no special instruments, that determined string-to-fret clearance (action) that was consistently repeatable. I wanted to be able to write down the string clearance of the top/bottom strings and place that information in my guitar case. When the season changed, my strings changed, or I suspected something was amiss, I wanted to be able to QUICKLY re-check those measurements and compare against the last set of measurements.

And it turned out that, after forty years of messing around with various other methods, the answer was simpler than anything I’d ever read: just use a guitar pick.

Huh ?

First making sure that your guitar is in tune, stand it up vertically and slip a heavy pick (most jazz guitarists use them) between the first string and a fret, say at the fifth fret for example. Gravity wants the pick to slip out and fall to the floor, right ? But string tension - in a guitar with low action - constrains the pick between fret and string.

To complete the measurement, one slips the pick between different frets, starting at a low one (around 3 to 5), moving up one fret at a time until the pick slips out. At that point, obviously the clearance between fret and string is slightly greater than the pick thickness. Write down the number of the fret. Repeat the process on the sixth string. (Make sure that the pick is constrained ONLY by the string being measured, don’t allow the pick to contact anything other than the string and the fret.)

OK, got that, but how is it a “measurement” ?

It’s a “relative” measurement (although it CAN be calibrated to yield “real” results), a comparative, qualitative measurement not quantitative. If you use the same pick each time, the thickness is constant. And by noting the fret number at which the pick “slipped out”, you have a record of the clearance which can be immediately re-checked in a matter of a few seconds. Do this on the first string and on the sixth string, write down the numbers, slip them into the guitar case and you’re done.

What is the significance of which fret the pick fell from or was constrained by ?

If, during the course of your adjustment, you are able to secure the pick in a higher fret than when you started, you are lowering the action (e.g. the pick used to remain in fret 5 without falling, you made some adjustments and now the fret will stay in fret 7 without falling. The action has been lowered about .005 inches – that is a significant amount and you will feel the difference when playing)

If you were trying to raise the action (and were successful), the pick would “stick” in a lower fret (e.g. you started out with the pick being constrained by fret 5 and now it falls from fret 5 but is constrained from falling at fret 3. You’ve raised the action by about .007 inches.)

Well, what constitutes a “good” setup, where should the pick be constrained on the first and sixth strings ?

It’s personal preference, defined by your attack, whether you play with a pick, your fingers, fingerpicks, and so forth. Don’t get bogged down in the detail of what the “right” measurement might be, the benefits of this measurement method: it’s FAST, reliable and invites easy comparison. You can try different adjustments and evaluate the results quickly. (Allowing adequate time for your guitar to settle into a new mechanical configuration, obviously.)

Let’s say, for example, your buddy just bought a new ES-175, you like the way that it plays and want to replicate the performance. Well, you sure can’t change the shape of the neck or your scale length, but you can easily determine the measurements of his action, using your pick, and then set up your guitar to those measurements.

You can even do this in a music store and make meaningful comparisons between guitars. BEWARE, however, those instruments are probably not set up as well as they could be. The entire idea – at least to me – FINALLY allows quantification of the phrase “low action”. Heck it just takes a few seconds to win a beer from the bass player as to whose guitar “plays” better. (Oversimplified, obviously, by ignoring other matters of personal taste, but the concept is simple.)

OK, accepting this - so far - is this really an accurate method ?

Yes. The average jazz guitar has a slope between neck and strings of approximately:

[(max string clearance @ 13th fret – min string clearance @ 1st fret)/(1/2 * scale length)], which

for a 25-1/2 inch scale guitar with string clearance of about .015 at the first fret and about .035 at the thirteenth fret gives a slope of about .00157.

Using a pick and inserting it between each fret in turn until it slips out will allow the detection of a string-to-fret height difference of [fret distance x slope]. For example, using an average fret distance of around an inch, one can easily detect fret height distances equal to the slope, or less than .002 inches (about as accurately as the dial indicator setup discussed above).

What if I have really low action, will this still work ?

Yes, just use a thinner pick, if necessary. The pick should be of an approximate thickness so that it just slips between string and fret about midway up the neck. But it’s not at all critical – we don’t care a piddle for exact measurements, we just want a measurement that is repeatable. If you use the same pick each time you make a measurement, it will be repeatable. Just record the fret number at which the pick could no longer be constrained by string pressure, when the guitar is tuned to pitch.

What if I like really high action? Use a thicker pick or some other object (credit card or other “light” object with the right thickness - don’t use coins or heavy items) and re-read the last paragraph. We want the friction beween pick (or whatever you use in place of it) and fret to establish the point of slippage …

Accurate, consistent measurement of “relief”, “clearance”, “action”, whatever you want to call it is CRITICAL to setting up a guitar properly. If you have no standard against which to compare, there’s no way to determine whether your adjustments are better or worse except by “feel” and you have minimal chance of making a good setup in a reasonable length of time.

Note that this technique presupposes that the nut is in proper adjustment, although it’s not highly critical for measurement/setup success unless it’s WAY too high. In fact, as a general rule, the first priority in instrument setup should be to address the nut, adjusting if required.

If you cannot grasp this technique at this point, it’s not your fault – it’s mine for not making it clear enough in writing. It would take about fifteen seconds to actually show how to do this and explain why it works (and works well). Try reading over a couple of times ...
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Whirly



Joined: 09 Mar 2008
Posts: 14
Location: Juneau, Alaska, USA

PostPosted: Fri Dec 04, 2009 8:42 am    Post subject: Reply with quote

Your two Setup guides are great. I wish I'd read them earlier.

I've been adjusting all my guitars to match my G&L ASAT Classic's neck. I think it's been plecked, I know it's perfect.

Just today I took a hammer (a little one) to my es-175 to remove the nut. The nut was off center with the high E string too close to the edge. I need to make a new one, but I don't have the files, blank nut, or skills yet. I'm working on it. The good news is the nut popped out with no damage. I replaced it with a little off-set. It made the guitar playable, almost.

Anyway, thanks again. I just wanted you to know there is at least one guy interested. Great work.
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JakeJew



Joined: 30 Jul 2005
Posts: 2190
Location: Boston, MA

PostPosted: Fri Dec 04, 2009 2:59 pm    Post subject: Reply with quote

Randy, I'm not much of a gear head, but do you have your own website? Seems like you have a lot of knowledge on these subjects.
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"Inspiration may be a form of superconsciousness, or perhaps of subconciousness - I wouldn't know. But I am sure that it is the antithesis of self-consciousness." - Aaron Copland
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randyc



Joined: 14 Sep 2006
Posts: 407
Location: Eureka, CA

PostPosted: Fri Dec 04, 2009 5:41 pm    Post subject: Reply with quote

JakeJew wrote:
Randy, I'm not much of a gear head, but do you have your own website? Seems like you have a lot of knowledge on these subjects.


No, I don't. It's my ambition to write down as much of this stuff as I can recall (especially regarding vacuum tube design) while my brain still works. Repetitive chemotherapy seems to nibble away at my memory, LOL !

I currently have over ninety pages of text collected, I write a little each night. My plan is to convert all of it to PDF format, graphics and all, and post it on one of the free web hosting sites.

Thank you for your interest. If I ever get the stuff organized, you can be sure that I'll post the link here.

cheers,
randyc
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sunflower



Joined: 09 Mar 2007
Posts: 581

PostPosted: Fri Dec 04, 2009 6:34 pm    Post subject: Reply with quote

Hi , In the spirit of getting the terminology agreed on

I've always viewed 'Relief' as the intentional concave bow some necks have applied to them..... apparently a slight relief can allow a lower action to be achieved ...
(never experienced it myself but there you go,
I like a fairly high action thick string set-up anyway)

Your writings are great Randy ....
It's very refreshing and informative to have the proper evidence-based
approach to information and techniques on these musical topics that you bring

Power to you
Jem
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JakeJew



Joined: 30 Jul 2005
Posts: 2190
Location: Boston, MA

PostPosted: Fri Dec 04, 2009 7:01 pm    Post subject: Reply with quote

randyc wrote:
JakeJew wrote:
Randy, I'm not much of a gear head, but do you have your own website? Seems like you have a lot of knowledge on these subjects.


No, I don't. It's my ambition to write down as much of this stuff as I can recall (especially regarding vacuum tube design) while my brain still works. Repetitive chemotherapy seems to nibble away at my memory, LOL !

I currently have over ninety pages of text collected, I write a little each night. My plan is to convert all of it to PDF format, graphics and all, and post it on one of the free web hosting sites.

Thank you for your interest. If I ever get the stuff organized, you can be sure that I'll post the link here.

cheers,
randyc


why not a book for profit?
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"Inspiration may be a form of superconsciousness, or perhaps of subconciousness - I wouldn't know. But I am sure that it is the antithesis of self-consciousness." - Aaron Copland
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Generic Sobriquet



Joined: 03 Jul 2007
Posts: 804

PostPosted: Fri Dec 04, 2009 7:53 pm    Post subject: Reply with quote

Because not everything needs to be for sale? There are things of greater value than personal financial enrichment?
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randyc



Joined: 14 Sep 2006
Posts: 407
Location: Eureka, CA

PostPosted: Fri Dec 04, 2009 10:25 pm    Post subject: Reply with quote

Generic Sobriquet wrote:
Because not everything needs to be for sale? There are things of greater value than personal financial enrichment?


Thank you, better stated than I could have said it.

JakeJew, my material is esoteric, as you know - not many would want to read the things that I enjoy writing about. Just you people here and a British forum where I post my technobabble.

I'm content with the status quo, I don't interact with people as much as speak AT them, regretfully. But it doesn't mean that I'm unaware of those that post here, especially you regulars and old-timers. I read everything and appreciate most of what I read.

cheers,
randyc
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