Modifications to Your Acoustic Guitar

Subject: Modifications to Your Acoustic Guitar
From: Moon'sGoin'Down
Date: 21 Nov 98 - 10:42 AM

I was talking to another guitarist recently and he asked me about how to go about improving the guitar's action. I know you can lower the stings, but I'm not really sure how or what methods there are to accomplish this without harming the guitar. Then I got to thinking that I've also read where people have filed their frets, added bone nuts and bridges, and other work. So I thought I would ask guitar players on the Mud Cat what they've done to modify their guitar to either improve playability or improve the sound? A related question: Do you need to bring your guitar to a luthier to modify it or can it be a "home improvement"?

Thanks,

MGD

Subject: RE: Modifications to Your Acoustic Guitar
From: Bill Cameron
Date: 21 Nov 98 - 11:41 AM

I'm not a luthier, but I play one on the Net...

Most guitars in the modern era have adjustable truss rods, the simplest and least invasive way to tweak the action. (Martins, until recently, being an exception--they have a fixed square tube in the neck, and are a job for a trustworthy pro.) They are accessible either from the peghead--theres a little plastic plate screwed onto it which you remove--or at the other end, the heelblock, accessed from inside the body. In either case, an Allen wrench is usually the tool to adjust with. Find the correct size wrench, slacken the strings, and experiment (usually from the peghead, turning the wrench clockwise will lower the action.) Do not force it--if it doesn't want to move its probably at the end of the thread and other measures are required.

If the neck is not really warped this will often correct the problem adequately. Other (trickier) measures include: deepening the slots on the nut, shaving the bottom of the saddle (plastic/ivoroid insert in the bridge that the strings actually touch), and lowering the bridge.

Then there's heat-straightening the neck--clamping it to a strong straight piece of hardwood, and leaving it with heat on overnight--this is tricky, and doesn't seem to work permanently in my experience. Sure wouldn't have it done to the Martin again. (ouch)

One other easy thing I've done with guitars with removable necks (Normans, Fender electrics) is to remove the neck and shim the joint with a bit of thin cardboard to change the neck angle. Outrageously low-tech, but it often works and can be undone if it doesn't--unlike bridge/nut surgery.

Improving sound: 1. play it a lot. 2. make sure all braces (on the underside of the top) are glued properly and not loose or cracked.

Good luck. If its a good guitar, and the simple fixes don't work, take it to a pro rather than messing with it yourself.

Bill

Subject: RE: Modifications to Your Acoustic Guitar
From: Ralph Butts
Date: 21 Nov 98 - 11:49 AM

MGD.....

You'll find some good info at the Musicians and Instrument Makers Forum: http://www.mimf.com/cgi-bin/WebX

The adjustments you talked about are fairly simple and can be done at home (with care - especially if cranking the neck). On the other hand, they can be done quite inexpensively by a good music store (with technician) or a luthier, if you have access to one. That would give you a good chance to discuss your instrument, and its strong and weak points.

Obviously, this recommendation is much stronger if we're talking about a fine instrument.

.....Tiger

Subject: RE: Modifications to Your Acoustic Guitar
From: Chet W.
Date: 21 Nov 98 - 02:51 PM

If your guitar is a fine one, like a Martin or a Gibson or any other that is likely to appreciate in value (as good a criterion as any) don't try these repairs yourself unless you are sure it is something that can be fixed easily if you make a mistake. There are so many fine instruments (my 1933 Gibson L-00 is one of them) that went through a period when they were worth next to nothing and home crafters nearly ruined them. A friend of mine says that you can't really own a fine instrument; You're just taking care of it for the next generation. I think there's something to that.

Chet W.

Subject: RE: Modifications to Your Acoustic Guitar
From:
Date: 21 Nov 98 - 11:49 PM

I tend to be more conservative. I would be cautious even with a less fine instrument. Don't go around filing the frets unless you really know what you are doing. If you mess around with the nut and the saddle, probably the worst thing that will happen is that you have to pay a pro to replace it (them). I think you can damage the neck if you start playing with the truss rod and you don't know what the final result should look like.

A setup by a mechanic is relatively cheap.

Murray

Subject: RE: Modifications to Your Acoustic Guitar
From: Dan Calder
Date: 22 Nov 98 - 08:49 AM

Ralph, Thanks for the link to The Musicians and Instrument Makers Forum. I popped over to take a "quick" look last evening when I first saw your post, and the next thing I knew...the evening was not only gone, but well on its way to becoming early morning. Wonderful stuff. Dan

Subject: RE: Modifications to Your Acoustic Guitar
From: hank
Date: 23 Nov 98 - 12:03 PM

If you want to try something, go to a pawn shop (or goodwill) pick up a cheep guitar. The worse it is the better (if there are any good ones perhaps leave it someone else if you don't want it) modify it to your hearts content. IF you do a good job with that insterment then consider working with your good ones. If you can't do a good job on a bad insterment you will only ruin a good one.

Subject: RE: Modifications to Your Acoustic Guitar
From: Bert
Date: 23 Nov 98 - 01:15 PM

MGD,
Bill Cameron has said most of it. But here's the way that I usually proceed. Like Hank I pick up junk guitars and play at fixing them.

No matter how expensive your guitar there are some things that you should check.
The clearance between the strings and fret nearest the bridge should be about 1/4 inch. If it's any more than that then you would probably get some benefit from lowering the action. File down the bridge insert to lower the action. You might want to buy a new bridge insert and nut before starting. They are very cheap and if you are making a habit or hobby of this you will want to keep one or two on hand.
Before you do that though you need to check that the fingerboard is fairly straight. First sight along the edge, hold the guitar on it's side and look from the bridge end towards the nut. It should be straight, but slightly concave is acceptable. If it's convex you can try adjusting the truss rod a little, but as Bob said, don't do too much. Slacken off the strings and turn the screw no more than a quarter of a turn at a time. Tune the guitar and see if there is any improvement.
Another way to check for straightness is to hold a string down at the first fret then push down on the string near the bridge. The string should touch the frets evenly all the way along.
If everything looks good then you proceed to playability testing.
Problems consist of buzzing of the strings on the frets. Buzzing of bracing under the soundboard. Bad tone, either too dull or too resonant.
For buzzing of strings on the frets first try raising the nut a little. Take the strings off or slacken them and pulll them aside. With a sharp knife pop off the nut, it should separate quite easily. Cut a slice from a business card and place it under the nut to raise it a little (it won't need any glue). String the guitar and try again.
If it's really bad and one fret is obviously higher than the rest. Then make sure that the fret is seated correctly. A little tap with a small hammer will take care of it if the fret has risen out of it's slot. Put a piece of wood or cardboard on the fret before you hit it.
If that doesn't work you can carefully file the fret down with a very fine file or emery board. Just a little at a time and try it frequently.

It's really a matter of observation and experience to know where to start. Take it slowly and have fun. Post any more specific questions here and you'll get lots of opinions.

Bert.

Subject: RE: Modifications to Your Acoustic Guitar
From: DonMeixner
Date: 26 Nov 98 - 08:05 AM

In my opinion regarding neck mods on a guitar you know and love or even one you just are attracted too. Don't mess with it. Spend the money and have a qualified mechanic do the work. I would even say have a shop replace the tuners if you are up grading from say, Klusen's to Schaller's even. This is an easy job but unless you are the owner of some GOOD tools and have a delicate touch don't mess with it. You run the risk of cracking the head stock between the holes. Don't try filing the frets unless you have fret files. They are quite expensive and not always easy to find. Working the action untill its perfect is not as easy as you would hope. Trying to pull down a neck that is otherwise straight by tightening the trussrod is courting disaster. Hideo Kamimotto's book on guitar repair is a place to start. Lots of information about necks and action. But practice on some corpses before you try a live one. All that being said, its fun to work on instruments and I build a few and fix a few now and then but I know where my limits lie. It takes more care and study then can be gleaned from a few posts on this forum.

Happy Thanksgiving Day to all, even them folks in foreign lands who view this day as merely a Thursday in November.

Best regards.

Don Meixner

Subject: RE: Modifications to Your Acoustic Guitar
From: Bo
Date: 27 Nov 98 - 03:03 AM

For the vast majority of musicians, you cant afford to make mistakes with your baby. Take it to someone you trust more than yourself. Hopefully you'll be happy with it and you can get back to playing. Don't begrudge them a few bucks for solving your problem if it means they take some responsibility for their work and it means they'll be there if you need them again.

Bo

Subject: RE: Modifications to Your Acoustic Guitar
From: Richard McD. Bridge
Date: 09 Dec 98 - 04:18 PM

I seem to have been lucky so far applying intelligence and a bit of fiddling to some quite decent instruments. People seem to have started coming to ask me to do things. Anyway, no way the neck of a guitar should be dead straight all along the fret tops. The strings should in theory always leave the frets at the same angle, whicheve fret is fretted. If you think about this for a bit, because the saddle is raided a bit, it means that there should be a very gentle arc to the neck. If it's too straight you will get fret buzz. Personally I set a neck straighter (and with a lower nut) than many and put up with a bit of buzz, but that's because I don't have a hugely strong left hand but like the sound of 13/58 strings if the table will stand it.

Subject: RE: Modifications to Your Acoustic Guitar
From: bri
Date: 09 Dec 98 - 09:59 PM

i play guitar, but i'vve never heard of doing these things. what do the certain things do for the sound?

Subject: RE: Modifications to Your Acoustic Guitar
From: DonMeixner
Date: 09 Dec 98 - 11:09 PM

Brian,

Its possible to make a guitar sound better by doing some work on the instrument. Many guitars are over braced and by removing some of the wood from the braces you can en liven the sound a bit. Remoe it from the correct place and you can make the trebles brighter, some place else and the bass sounds fuller. A slightly smaller mass in the bridge and the top vibrates cleaner and longer.

HOWEVER! remove too much material and the whole thing comes apart. But done well by a person skilled at "Voicing" a guitar and even a Martin can be made to sound good.

DonMeixner

Subject: RE: Modifications to Your Acoustic Guitar
From: Art Thieme
Date: 11 Dec 98 - 09:10 PM

As I said elsewhere, I drilled 3 extra holes in the peghead of my Martin D-76 and put 3 straight-through banjo planetary gears into those holes. I kept the bass strings single for clear bass sound for Travis picking. I doubled up on the first 3 strings & had 3 pairs of unison strings. The ball ends of the pais of strings went 2 into each hole on the pin bridge. Guide grooves were cut into the raised bridge bone.

Was a 9-string guitar. (After Big Joe Williams who I followed around Chicago when I was younger.)

Art

Subject: RE: Modifications to Your Acoustic Guitar
From: GUEST,Owen
Date: 21 Apr 10 - 09:13 PM

I recently tried to file the nut and the bridge of my acoustic guitar. I forgot that you can easily remove the plastic bridge saddle that the strings rest on near the sound hole. This was a big mistake and I now need to buy a new saddle peice. Just a friendly FYI. My guitar does sound and play much better than it did before. I agree with the other gentlemen who said buy cheap and fix up. That's what I do now and have a great sounding and playing guitar to show for it. GUITAR BUYING TIPS: If you are buying a used guitar look at fret wear, neck alignment, action, electonics, and sound most importantly. Fret work is the most expensive while action is the lower end of the set-up. I had my the frets dressed on a brand new guitar because it was buzzing high on the scale. The guitar was a cheap one and not dressed from the factory. This would cost about $70 depending on where you go for service. Refretting can costs about $150 if your lucky. The bridge peices are relatively cheap compared this. So look for good frets.

Subject: RE: Modifications to Your Acoustic Guitar
From: open mike
Date: 21 Apr 10 - 10:52 PM

i had pearl inlay pegs added...the ones that hold the bottom of the strings...and new tuners added...and an internal mic type pick up..
mini-flex microphone..for amplification...this has given my much greater options for sound and the main thing is that i do not have to stand right by a stationary mic stand to play.

see mini-flex microphone on line..

Subject: RE: Modifications to Your Acoustic Guitar
From: banjoman
Date: 22 Apr 10 - 05:40 AM

I replaced the plastic saddle pins on my Lakewood with a set of Brass pins and the result was quite significant as it gives the instrument a lot more resonance - I dont really know why such a simple action should produce such good results but it did and I can reverse the procedure if necessary

Subject: RE: Modifications to Your Acoustic Guitar
From: Dave the Gnome
Date: 22 Apr 10 - 08:30 AM

We have a Marlin electro-accoustic as our 'house' guitar (see other thread).

Well, I should say it WAS electo-accoustic and it never sounded too good. We removed the internal pick up, battery, wiring and extenal knobs and it sounds fine now!

Go figure, as they say west of the pond.

DeG

Subject: RE: Modifications to Your Acoustic Guitar
From: buddhuu
Date: 22 Apr 10 - 09:35 AM

I always set up my own guitars, mandolins etc.

One of the best resources on the web, IMHO, is Frank Ford's Frets.com site.

Adjusting action is something well worth doing oneself. It's generally simple enough to do. The biggest hurdle is that of mustering the nerve.

My own policy is to keep a few spare nut and saddle blanks around. I always work with a new nut and/or saddle, taking the originals off and keeping them in a safe place, unaltered, so I can restore the original situation if things don't work out.

With respect to earlier posters, while the truss rod can be used to tweak action, that, per se, is not its primary purpose. The truss rod adjusts neck relief (the amount of "bow" in the neck). Yes, this does adjust action, but if the nut and saddle aren't right then the truss rod will not be able to set the action by itself.

I have always been taught that the order to address things in setting up a guitar would usually be:

1) Set action at the nut
2) Set action at the saddle
3) Adjust neck relief with the truss rod

That has always worked perfectly for me.

Setting action at the nut is the place to start because there is a single broad rule of thumb that works for most guitars and most players.

See Frets.com's article on setting the nut.

Again, just MHO, but I would also recommend filing individual nut slots rather than sanding the nut down at the bottom. Fixing one over-cut slot is more easily and satisfactorily done than shimming a whole nut that's been taken down too far. Shims for nut or saddle are an imperfect compromise at best.

Bridge saddles, on the other hand are most quickly set by sanding the bottom. Doing it that way means you don't screw with any built-in string compensation on the saddle.

Bear in mind that however much material you sand off the bottom of the saddle, the corresponding adjustment in string height at the 12th fret will be about half. E.g., if you sand 3mm off the height of a saddle, the string height at the 12th fret will probably be lowered by something in the ball-park of 1.5mm.

Apart from the nut setting, other set-up elements are matters of personal preference. Some people like low action at the saddle, others like high for the tonal and volume benefits, and the fact that they can play harder without buzzing and rattling.

Similarly neck relief. Some people like very little, others like a little more bow in the neck.

This stuff is all pretty simple, but needs to be done with care.

Once again, if you keep the old parts unchanged, you can always restore the status quo if you discover you don't have the knack for tweaking.

[/ 2 cents] Feel free to ignore.

Subject: RE: Modifications to Your Acoustic Guitar
From: Backwoodsman
Date: 22 Apr 10 - 09:45 AM

I think you need to reverse 2) and 3), Buddhu. Work one direction only - head towards bridge.
1) Set action at the nut
2) Set neck relief
3) set action at the saddle.

If you try to set the saddle-height before you set the neck relief, chances are you'll end up having to re-set the saddle height, either by sanding some off or adding a shim (or making a new saddle of course!).

Subject: RE: Modifications to Your Acoustic Guitar
From: buddhuu
Date: 22 Apr 10 - 10:38 AM

Yep, you're right. I'll go along with that.

I demoted truss adjustment because I have so rarely found it needs adjusting, and because it can be one of the more confusing things for a newbie to adjust. In the last dozen or so guitars I've seen and the last half-dozen mandolins, I've probably tweaked two rods in total - neither by more than a quarter half turn.

Maybe I should have left it off the list, or suggested leaving that aspect to someone with experience. As you'll know, a busted rod is a far bigger pain than a messed up nut or saddle.

But yeah, assuming all three need attention, you're quite right.

Subject: RE: Modifications to Your Acoustic Guitar
From: Richard Bridge
Date: 22 Apr 10 - 11:29 AM

I'd disagree on the order and some of the substance.

You can't set the action unless the frets are right. Remove strings, and adjust truss rod (or use a jig and clamps) so that the neck is straight. Check with a straightedge (a pice of ally extrusion used to make flightcases is accurate enough, usually, and it has the advantage that you can cut it so that it just fits between the nut and the bridge plate). If that straight edge finishes up more than about 1mm below the top of the bridge plate, panic, because you need a neck set. Go to a professional (and a good one who will not take damaging short cuts like over-filing the middle frets).

If your straight edge sits nicely just on the top of the bridge plate all is well. Now you need a short straightedge that is very accurate. You may be able to make do with a bit of cut glass or a broken (straight edged) file. You may need more than one such becuase ideally you wnat it long enough to sit along three but not four frets. Stew-Mac sell a tool for this.

Work along the fretboard. If at any spot the straight edge sits up on the middle fret and rocks between the other two you have a high fret. It has to be fixed. Is the fret firmly down to the fretboard? If not you may be able to tap it in with a tiny hammer. do not go mad. If it won't stay in, you can try running a little very runny superglue in and carefully clamping. Don't forget to protect the back of the neck. This does however pose a problem for teh future when a refroet becomes necessary as although superglue will usually break cleanly to a sharp tap, it won't always.

Once all your frets are well seated, inspect for grooves.

If you are left with any high spots or low spots or grooves deep enough to cause unevenness in playing, you are going to ahve to dress the frets. Use as long a flat fine file as you can work with (or a long flat oilstone, or you can get away with emery cloth and some STRONG plate glass or a mirror but be careful not to break it) and smooth the frets up and down the neck until every single one shows it has been evenly kissed by the abrasive.

You should now crown the frets with a special tool, but if you can find one of those things with holes in that soldiers used to use to polish their brasses, or if you put two thickneses of electrical tape just next to each side of each fret to protect the fingerboard you can slightly crown the field angles with fine emery cloth or steel wool.

Now clean the fretboard and oil with lemon oil. Re-string guitar and proceed to neck relief.

There is only one correct neck relief: it's the curve such that the string always leaves the fret at the same angle. My first reaction is that this is geometrically impossible with the available tools - I have a horrible feeling it is going to be a parabola not a segment of a circle. But it can usually be approximated. Capo at first fret, and press string to fret at the neck/body join. Measure the clearance string to fret at the midpoint. You need feeler gauges for this. 0.25mm or a smidgeon less is good. Adjust with truss rod until right.

Now you can do the saddle. There are two issues - does the curvature follow the curvature of the frets? How high is the action? Capo at first fret. Using feeler gauges measure action at 12th or 14th fret. You probably want about 2.5mm on bass and about 1.7 treble. More if you play bluegrass with a 1mm pick, less if you do ethereal fingerstyle with your nails. But the first step is that you want the respective heights to reduce progressively and uniformly, so if you wanted 2.5 to 2.0 it would be bottom E 2.5, A 2.4, D 2.3 G 2.2 B 2.1 E 2.0. You can adjust the relative heights by tweaking each string aside and grooving the saddle. Write down what your measurements were! Don't worry at this stage if all are too high still, just get the progression right.

Now slacken strings and remove saddle. Freehand upside-down on sandpaper or emery cloth or a fine file, make a nice arc of the top of the saddle until your grooves all just disappear, and then barrel the top of the saddle. I am not going to talk about intonation (yet). Now on a flat turface like a mirror file the bottom of the saddle until you have removed the right amount so you have reduced and angled (sideways) the bottom of the saddle to give you your desired (say) 2.5 to 1.7.   NB, if you are installing an undersaddle bug you may need to chamfer the bottom of the saddle so it will sit correctly on the bug, and different makers ahve different views as to what is right.

Finally you can do the nut. There is only one right height for a nut slot. It is the height such that if you capo at the first fret and measure the clearnaces at teh second fret, then take the capo off and measure the clearances at the first fret, they should be the same. The nut slots should be done with special files with rounded edges so that the bottom of each slot is the same as the string that will sit in it. The angles of the nut slots are critical too, to avoid string grab when tuning. Both sideways and vertically the string should leave the nut slot at the same angle and if you are really OCDC you can barrel the slot vertically to reduce the break angle at the rear.

Of course, I can't actually DO it like a pro, but I understand the reasoning!

Subject: RE: Modifications to Your Acoustic Guitar
From: Backwoodsman
Date: 22 Apr 10 - 12:12 PM

You may well be correct Richard, but I think Buddhuu and I were probably working with the KISS principle, for people who have very modest DIY skills.

there's a wealth of stuff out there for then serious amateur-tech-luthier type of guy, Frets.com or www.bryankimsey.com/music/lutherie.htm to name but two (which I know are good resources).

Dressing and crowning frets is probably the kind of thing that even the most enthusiastic amateur should practice on an old, low-value instrument before starting to fart around on a decent guitar?

That's IMHO, of course and, if you're a braver man than me, Gungha Din, YMMV. :-) :-)

Subject: RE: Modifications to Your Acoustic Guitar
From: Backwoodsman
Date: 22 Apr 10 - 12:15 PM

And, of course, even the Superstarsstars of Luthierie disagree about almost everything to do with their art at some time or another! Check out some of the debates on some of the internet guitar-forums (fora?).

Subject: RE: Modifications to Your Acoustic Guitar
From: buddhuu
Date: 23 Apr 10 - 05:07 AM

The builder forum on MandolinCafe is a brilliant place to see that demonstrated, LOL.

Bearing in mind the uncertainty in the tone of the OP, I would not encourage someone with little or no experience to experiment with anything more than the nut and bridge saddle - and even those only after putting the originals somewhere safe.

Subject: RE: Modifications to Your Acoustic Guitar
From: Backwoodsman
Date: 23 Apr 10 - 06:09 AM

Likewise, Buddhuu, couldn't agree more.
Knowing the length, breadth and height of your own skills is as important as knowing the methodology involved in luthiery, and it's the key to avoiding tragedy. :-)