William Cumpiano's 
String Instrument
Newsletter #2




























Hubris and kinky fingerboards...
William R. Cumpiano 2002, All Rights Reserved

Yes, I've been away. This newsletter is a victim of my website's own success. It's made me so busy that I have hardly any time left to keep the Q & A's appearing regularly as I had hoped. But this one's REAL big. Hope it makes up for your long wait.

Kinky Fingerboards

I set & glued the neck on my first guitar today, and ended up with a kink in the fretboard and my question is as follows: If I start out with the heel square to the fretboard, then the fretboard starts parallel to the soundboard. The thickness of the fretboard at its highest is 1/4" (7/32" billet thickness at centerline + 1/32" approx fret height = 1/4"). With the fretboard parallel to the soundboard, the airspace between the soundboard and the line of the fretboard at the bridge (neglecting the effects of the domed soundboard, which in this case seems to have a neglible effect) would therefore be 1/4". You suggest an airspace of 25/64"-7/16". For the sake of this inquiry, lets go for 13/32". So in order to increase the airspace 5/32", we need to back-set the neck slightly. The neck will rotate around the neck body junction at the 14th fret, slightly behind the center of the scale, causing the nut to be offset slightly more than 5/32" below its original position. So now the whole fretboard is rotated slightly away from the plane of the soundboard, causing the end of the fretboard to lift off the soundboard. The problem comes when I must glue the fretboard to the soundboard: The fretboard up to the 14th fret is back-set from the soundboard, but the fretboard from the 14th fret upwards must be parallel to the soundboard, causing a kink in the fretboard at the 14th fret where these two different planes intersect. Did I do something wrong? Is this supposed to be the case? It seems to me that this situation presents no problem to the first fourteen frets, where the strings are practically parallel to the fretboard, but beyond that, the increasing action would cause progressive pitch distortion. Is it perhaps a negligible effect? Or is something wrong with my procedure? Please help to clear my confusion.

To have the fretboard "dive" where it meets the soundbox would be a serious flaw in a good guitar. Keeping the fretboard continuous across the neck/body joint is one of those things that separates the men from the boys (and the women from the girls) in this business. A diving fingerboard end makes playing in the highest regions of the fingerboard virtually impossible.

Remember, the upper transversal face brace is supposed to be arched slightly. It should be arched sufficiently to raise the soundboard to meet the fingerboard. If it was arched insufficiently, the fingerboard end has to be pushed down to meet the too-flat soundboard, which results in a diving fretboard. Try a greater upper transversal arch next time (as a patch on your existing guitar, adhere a fine wedge of matching fingerboard material under the fingerboard end to support it in a straight-to-the-end configuration--when finished, the fingerboard end may imperceptibly seem to swell slightly in thickness).

Also, when you glue the back onto the guitar, you have to take great care to keep the headblock rigid during the gluing procedure, because if it is carelessly allowed to tip in either direction, its going to drag a bulge or hollow on the soundboard precisely where the fingerboard end is going to lie. Since writing the book in 1985, I've improved my headblock fixturing technique in this regard by devising an extension to the workboard shoe (the bolted-down wooden stick that clamps the soundboard to the workboard through the soundhole), so that I can actually bolt it right to the back face of the headblock (through a hole in the headblock mortise) with a large screw. That locks it securely, keeps it from tipping when you clamp the back on, but can be unscrewed to remove the soundbox from the workboard. The mating face of the shoe's extension (where the shoe reaches to butt up to the back of the headblock) must be ground to the desired orientation of the headblock, i.e., strictly perpendicular to the soundboard.


[ed.: This is my response to a guy who wrote to tell me that since his first guitar sounded so good, he began to sell all his subsequent guitars. He was apologizing because he had come across one of my writings on this website, titled A Pedagogue's Lament, where I admitted to a deep, dark fear that my dispensing so much easily-available and advanced guitarmaking information to the general public could actually result in the creation  a crop of "mini-Frankensteins" -- overconfident beginners with little experience spreading all across the landscape selling their half-baked instruments to unwary guitarists--while claiming that they had been guided/apprenticed by William Cumpiano. He apologized abjectly for having done just that, and learned his lesson when his early guitars started to come back with problems that he had no idea from where they came or how to repair. My response:]

There's nothing wrong with being very proud of your work, especially when it is a first guitar that came out very well. And there's nothing wrong with selling your early guitars to friends either--except when something goes wrong with it and it comes back and you don't know what to do ("why does it buzz sometimes on the E string?...and the A string isn't as loud as the others...")...or when inexplicably, it comes out sounding dull and crappy, when you thought you had done everything the same as that glorious first one.

Its EXCESSIVE pride that is the problem you've got to watch out for. That's called hubris, and I guarantee you, the guitarmaking gods will immolate you in wrath and fire before your fourth guitar is completed if you don't control it. All you've REALLY accomplished on the completion of your first guitar is that you went through the sequence... once. Be proud of your recent display of tenacity and perseverance in the face of great odds. But knowing the steps in the proper order is really just the start.

MY own first instrument was an unmitigated disaster. And no, by writing the book, I didn't pay all your dues for you. You still have a big handful of dues yet to pay in order to achieve consistency, efficiency and self-confidence in your work.
Guitarmaking is very, very, difficult. It happens very slowly and thus it doesn't pay very much. There are a lot of better guitarmakers than you out there, and there will always be, so watch out for your thinking that you can beat them at this game. You think you can get people to pay you for all this fun? In fact, you are likely to learn that YOU are the one who has to pay in order for the world to let you make guitars. Now live with THAT. Your hubris will magically disappear before long, if you have any. And if you emerge in pretty good shape after all that, THEN you can be truly proud.

On floating fingerboards

Just a quick question. Do you use any glue under the fret board above the sound hole when bolting the neck to the body [when using the recommended hardware neck-joint]?

Yes, of course. However, if you've worked precisely enough, and the upper face brace arch correctly anticipates the neck angle, the end of the fingerboard won't "float" at all, and you can actually assemble, string up and play the guitar without any glue there at all. Lately I've been stringing the guitar up in the white (before finishing, which allows me to make final tonal and other adjustments before finishing) by gluing the bridge onto the bare soundboard "temporarily" -- that is, by applying a light skin of Elmer's glue to the bottom half of the bridge, well within its southern half. This is actually sufficient to hold tension for several weeks if necessary, but light enough to remove with little fuss and a broad palette knife with trivial or no damage to the sound board. When I'm ready to finish, I remove the neck and tape off (with "safe release" masking tape) a portion of the bridge's "footprint" so that the finish won't infiltrate the slightly chewed up area. After finishing I glue down the fingerboard end to the bare portion on the top, as described in the book. The notes played on the fingerboard sound simply terrible if the fingerboard end is allowed to float, snug as it may be, however, without glue.

An extended conversation about classic truss rods

Recently, a friend drew my attention to a newsletter of yours in which my guitars had been referred to. I though I would write a quick note to give my opinion of the question about classical truss rods. You refer to the inclusion of truss rods in classical Guitars as "silly". I started using them for several reasons. Firstly I've seen and repaired many classicals with far too much relief after a few years of string tension so they DO BEND! Secondly, humidity plays as important a role in neck straightness as string tension. The ebony, being unfinished, absorbs moisture and dries out when the seasonal humidity changes and bends the neck back and fourth. In low humidity, the action will be higher as the
fret board shrinks and the neck bends forward, in high humidity the fret board swells and the action will be lower. Pre loading a neck with the truss rod and planing it straight before fretting will stabilize it. Thirdly, a truss rod stiffens the neck, and as the neck absorbs half of the energy of the vibrating string and transfers high frequencies back into the mix of sound in an instrument, this has a very marked difference in the tone.

As that comedian Dick Gregory used to say, "I'm a vegetarian, but I'm not going to take the steak off your plate," you're welcome to your own mental model of how you perceive things happen on the guitar. My perceptions are different.

I disagree with your hypothesis that the fingerboard's swelling and shrinking causes the neck to back- and forward-bow. The course I audited with wood-tech expert Dr. Bruce Hoadley at UMass persuaded me that wood expands and contracts perpendicular to the grain direction (so the fingerboard will expand and contract in width, not in length). So the explanation for what you observe doesn't seem to square with what I've learned about wood's behavior.

My experience with high or changing action on classics does not point to the neck bowing (that is, curving) forward as a result of string tension, but of other distortion elsewhere on the guitar which causes the action to rise and fall and so would not be resolved by simply tightening a truss rod (if it were there). Also, I still feel that the tension load across the length of the neck dumped by what essentially amounts to floppy fishing line is insufficient to curl up mahogany, steel (when present) and ebony.

The rest of my original questioner's response that characterized classic truss rods as "silly" specified the ADJUSTABLE kind. Indeed, I pointed out that the mass of a NON adjustable rod,  caused a noticeable and perceptible increase in sound quality. So I have no argument on that account, only to caution you when you readily ascribe specific acoustic effects to what you're doing as a known fact, ("as the neck absorbs half of the energy of the vibrating string and transfers high frequencies back into the mix of sound in an instrument") when actually (and presumably) you're not a trained acoustician and you really don't KNOW why it's doing that, but are just guessing. Indeed, a real acoustician would be far more hesitant to explain ANY acoustic phenomena on a guitar as easily as you apparently can (but don't take it personally--its a quirk of the profession for us luthiers to readily and regularly do just that). I've learned just enough about guitar acoustics (Associate Editor, Journal of Guitar Acoustics, 1884-86) to be very careful about spreading my own homegrown notions about acoustic phenomena around as if they were fact. There is very little known for certain about how guitars work and the energy interactions within them  because these are so incredibly complex, and so little definitive work has been done to find out.

Please remember that I didn't call YOU "silly" just your choice of truss rod design. So I regret if there was any insult or discomfort caused by my writing, it was not intended.

Just another short note. Let me modify my statement. "My experience has led me to believe that the high frequency absorption of string energy through the fret board of a guitar has a marked effect on the tone". The essence of my use of a truss rod is to pre load the neck. In fact what made me start using them was a problem with back bowing necks. Again, my experience with imbedding non-adjustable materials in the neck led me to suspect something was occurring with the epoxy shrinkage causing back bowing a few months after the instrument was finished. The solution for me was to use a two-rod system that does not compress the neck and to pre load it so I could cure a back bow (just as important as a forward bow and more likely in a classical.) Perhaps the "floppy fishing line" I string my guitars with is not enough tension to stabilize the wood, if it has a tendency to bow. It also follows that a neck under less tension is more likely to react to internal stresses in the timber.

About the longitudinal expansion of wood, obviously wood expands more across the grain as it absorbs moisture. I have hygrometers built from strips of spruce (long and cross grain) which I keep in my humidity controlled workshop. Spruce expands five times as much across the grain as along it but the longitudinal expansion is indeed measurable. I hate to disagree with a wood tech but I have direct evidence to the contrary. (I wonder if his opinions can be taken as known fact). This leads me to believe ebony probably does much the same thing. This, coupled with the fact I get a rush of set-ups (on solid bodies too) whenever the season changes here indicates the expansion and contraction effect of fret boards quite clearly to me. I get actions that need lowering in the dry season and the opposite in the wet. A truss rod adjust is normally all that is needed.

Regardless of whether you think my views are valid or not, a guitar costs me $230 to freight from Australia to the US. A return warranty for a neck problem will cost me $460 in freight. A truss rod costs about .30c to make in materials. Since using truss rods I have never had a problem with my necks. I constantly am complimented on my set-ups which are possible through the fine adjustment of neck relief after the instrument is assembled. No offence taken but hardly "silly"!

I might also point out your statement (which I agree with) about "the mass of a NON adjustable rod, indeed caused a notable and perceptible increase in sound quality" is a very subjective statement. Do you KNOW its doing that or are you just guessing?...... presumably you're not a trained acoustician either. I bet we both have buckets load of experience.

Thanks for your message. Yes I KNOW there is an improvement in sound. No, I DON'T KNOW why. Try playing the guitar while someone sneaks up behind you and clips a padded cam clamp to the headstock. Wow. Big change. Louder, fuller. Then have them remove it. Change goes away. Then have him clamp a padded cam clamp across the tailblock. Let me know if you perceive another change. What does it mean? Who knows? All I get out of that is that neck mass good. "My experience has led me to believe." Aah, how refreshing to hear that from a fellow luthier! A very rare remark, Indeed. Usually its something like, "I make the soundholes oval because soundholes are like hoses. When you squeeze the opening, it makes the sound shoot out farther" (Jimmy D'Aquisto, lecture at Symposium 89). Or "arching the back makes it into a reflector that focuses the sound in front of the guitar and so it projects more" ad infinitum. Do you KNOW that the epoxy in the fingerboard seam shrinks? Epoxy isn't supposed to shrink, I thought. Or does "experience leads me to believe"? At the shop that I was trained we used white glue under the fingerboard and sponge soaked with water the BACK of the neckshaft at the time we glued the fingerboard on. We used a massive fingerboard caul and kept it clamped until the water dried fully on the back of the neck. I don't remember a single back-bending problem. Like you, we did pre load the necks and planed the fingerboards flat again. But this was on steel string guitars. You do that on classics?

    Yes, the clamp on the head stock trick. I'm aware of this. I theorize that the increased mass means it is harder for the neck to move in response to the vibrating string and therefore it doesn't damp the sound as much. Kasha used to put weights in the head and more in the tail block for balance. I believe some frequencies need to be damped. A really loud guitar with uncontrolled frequencies sounds really muddy in the inner voices.
    The only problem with water-based glues in fret board attachment is the wood expands across the grain with the water absorption from the glue then slowly shrinks back over a year or so. With an unbound fingerboard the fret-ends start poking out a bit and need redressing. I now use polyurethane glue for this job.... Its great! and it absorbs moisture from the wood as it cures.

Wrestling with back braces

I'm wrestling with back bracing. In the text you want two 14" and two 18" brace blanks cut (ss). Then the next step is to arch them at various offsets. I note that when I place the blanks against my outline that the offsets will be nearly cut off when the blanks are finally cut to the proper length as they are wider than the guitar outline. My outline has a particularly narrow waist so this is especially true with the number two brace.

I cannot recall nor locate any discussion in the text about the final length adjustment for the blanks. I seem to remember having this same problem with my first guitar and everything turned out ok, but I cannot remember what I did. I have decided that the offsets refer to final dimensions (i.e. the braces are cut to length against the outline) and have acted accordingly after referring to a couple other manuals and after noting the pictures of the braces drawn in your text which seem to indicate that that is what you had in mind. I've noted that other writers vary widely in opinion. Some offset the same height at each brace while some make no mention of it at all and basically provide plans for building a flat back. I wonder how critical it is but have decided that as long as a decently consistent, yet subtle arching is achieved, all will turn out.

Doubt gnaws at me, however. Would you be so kind as to clear this up for me please?

The back should definitely NOT be made flat. It should be arched--and the precise amount is not critical. What's most important is...NOT flat. The back is arched, by my reckoning, not to turn it into a "sound reflector" as the popular myth has it, but for the following reasons:
     Structural reasons: A domed back imparts greater rigidity to the entire soundbox structure.
   Aesthetic reasons: A flat back looks sunken. A slightly domed back actually looks flat. A noticeably domed back is an excessively domed back and looks a bit peculiar on a guitar.

The only practical effect of arching the back radically is to increase the air volume inside the soundbox. To the extent that it does, it has only a peripheral effect on the guitar's sound output. So don't lose a great deal of sleep over this matter.

I would advise you, rather than try to set your guitar back to a precise arch, just pick a likely arch offset for an arch template, curve all your back braces to the same arch template (don't worry if the one at the waist has most of the arch eaten away--if you increase it, it will just impart a lump to the back) and just strive to understand the spatial relationships of the back arch to the contour of the rim of the sides, so that it sits well on the rim without any lumps or bulges. It's a spatial relationship which seems difficult when explained with words (try to explain an accordion with your hands tied behind your back!) but really is quite simple.

Square-tube neck rods

In your 19th newsletter, you write "I put a 3/8" square steel tube in my classical necks. As many luthiers have discovered, placing more mass in the neck can increase volume and enhance trebles". Some questions:

How long is a typical square steel tube?

The ones I get are about 12" long

If shorter than nut-12th fret, is it centered between those points?

No, its closer to the nut.

I expect that you route a channel to hold the steel. Do you use glue it in
place? If so, what kind of glue?

Epoxy. On all the surfaces. Make sure it doesn't rattle under your fingerboard!!

Decorative notes

I have been admiring the Beeswing Mahogany Wedge Cutaway 12 string shown on your website and I must say I am quite taken with it.

Wedge 12 front 4.jpg (44444 bytes)

The decorative strip around the soundhole is especially elegant. Did you make it from the same mahogany as the sides? Is it cut from a single piece or laid in with strips? My first attempt using pearl was atrocious, and since I saw what you did with that guitar I don't see any reason to fight with the expensive pearl until I have the rest of it down a little better.

The novel decorative treatment around the soundhole is a 3/16" thick mahogany "doughnut" I created by spinning it out of a square blank on the drill press with a fly-cutter.

Pinning-Pliers Fabrication questions

(Ed.: Pinning pliers is (are?) the device that my guitarmaking book specifies for squeezing the tapered pins into the headblock through the soundhole.)

Are all bends made in a horizontal plane to the flat side of the section? The picture on page 328 seems to indicate that one of the ends is bent slightly with the thinner edge. Also, a question on the final seating of the pins: are both pins seated at the same time with the pliers? It seems as though the ends of the pliers would have to be offset from each other if this is the case.

It is easier to make both arms flat. And that should work ok. However since one arm is on top of the other, when you press the pin in, the force won't be applied in direct line with the pin, because the opposing arm is just above (or just below the other). I improved the action a bit by bending one jaw up so that it would be in line with the other.

No, the system is designed for two pins coming in from opposing directions, one above the other, and inserted in sequence, as described in the text.

I don't know how far you've gone in the process, but on my website I've recommended and describe a modification of the neck joint which doesn't require pins or a pinning tool. The book was written over fifteen years ago, and I've put that system aside because it is too complex and potentially problem-prone. You can find the recommendation for the simpler (and better) joint on this page.

What a neat and elegant idea; although a bit tough to swallow for us atavistic types. I do appreciate it however. Wish I had seen it earlier, since I have the tenon and head block drilled and reamed, the pins made, etc. what do you feel my final chance of success is?

As long as you drill the offset holes in the tenon no more than 1/32-1/64 -inch offset in the correct direction, you should be ok.

Are all the overall measurements for the block and tenon, as related to the new joint system, the same as published?

You can still retrofit your headblock and tenon for the barrel bolts. I've "upgraded" several old Cumpianos that way. Drill the oversize holes through the headblock, and ignore the side holes. Fit a homemade drilling guide over the tenon, to guide your drill for the barrels. Then drill the smaller access holes through the end grain of the tenon to intersect the holes for the barrels.


What would be the consequences of spraying a high gloss nitro finish on a matte finish, such as a Martin D-15? Would it kill the tone? Could/should it be lightly/finely sanded first?

No overspraying won't "kill" the tone. But over-spraying overspraying could. Put just enough to polish out, not much more. And, yes, you want to first sand it down first with 400 grit open cote carbide (dry) paper (get it in an auto paint/parts store) and then wipe it all down carefully with Prep-Sol (a degreasing solvent--also from auto paint stores) to get all the accumulated goo off it.

Slitting purfling strips down the middle

I'm about to bind my guitar, but I'm unsure how to proceed. The purfling ledge on the top is roughly 1/16" deep (I don't want to go through the soundboard, do I?), but my purflings are 3/16" tall. Do I cut them to height before installation, or do I put them in tall and then plane them like the rosette? The illustration in the book shows them flush, but .. Can you advise me?

Many builders, even some good builders insert purflings which are the same height as the bindings. This simplifies the process, since you have only to rout a single large mortise rather than two smaller ones. I'm uncomfortable with recommending this as a general rule because it leaves precious little of the top remaining on the linings/kerfings. I feel it is a better structural solution to leave a portion of the soundboard remaining under the purflings.  If you do rout a binding/purfling "staircase" you definitely want to reduce the size of your 3/16" purflings Otherwise, they'll twist and break when you tape them on or when you plane them down. No good.

You'll have to reduce them in height to something closer to the depth that it's corresponding mortise allows, maybe 3/32. If you're careful, you can slit them down the middle and get two full length, half-height strips.

To do that you'll have to find a yard-long metal ruler or straightedge. Clamp the ruler on top of the strip lengthwise along the edge of your worktable, so that 3/32 of the strip peeks out over the edge of the ruler. Then take a brand new, sharp X-Acto razor knife and draw it down the length of the strip, pressing more firmly against the straightedge than into the strip. The trick to get a perfect job is not to try to bully through the entire thickness of the strip with two or three passes of the razor knife: if you're not patient, the strip will cause the blade tip to wander and you'll spoil the strip. What you need to do is make many, many LIGHT passes, at first almost too light to make any difference, and then a bit more firmly as the blade finds it's way through the strip. Now after 10-12 swipes you'll think you should have cut through by now, but don't be fooled. Keep up your
light patient strokes with the blade, even if it takes 10-12 more strokes, until the strip is fully and cleanly severed in half. If you bully or rush the job, you'll spoil it.

You often have to reduce the size of marquetry purfling strips, which often come at a thickness greater than 3/32". The thicker marquetry strips are actually used for laminating full height between the two bookmatched back plates. At that size, however, they are inappropriate for use as soundboard purflings. These have to be reduced in height. To do so, you'll have to saw or rout a straight, full-length slot in a board that will accept the length of the strip at a depth equal to the desired final height of the strip. A little dot of glue at one end of the slot will keep the strip from moving once you've placed it inside. Then proceed to scrape of the excess with a sharp scraper blade held at a bias, or angle, so it slices cleanly through the marquetry without pulling any of the pieces out. Continue scraping until you hit the board.

Hollow-dome building forms? Not form me...

I am building Irish Bouzouki's for now and am on my third one, one actually went to Ireland for my friend. My question is about the workboard dishing for the radius of the top, using LMI's [Luthier's Mercantile International] method of making a radius board with a router, where would the center be for the radius? I have been using a 25' radius for the top of my bouzouki's using the bridge location for the center.

I wonder how folks are persuaded to build on a hollow spherical form. I don't quite comprehend what the advantage of that is, particularly since I know of no precedence to the assumption that the soundboard is supposed to conform to a section of a sphere. And even if it was, the contour of the rim is not presumed to be the result of its intersection with a sphere--it's supposed to be flat. If you impose a spherically domed soundboard onto a flat rim, the soundboard is going to have to distort to accommodate itself. Oh well...

Since I don't see the guitar top in terms of a precisely radiused dome I really can't speculate what the precise radius is or should be. My technique is to just arch the braces so the top is "not flat", for strength purposes, and keep the brace arch dimensions consistent with the setback angle of the neck, so the end of the fingerboard doesn't dive.

I can see I was not clear in my question. Looking at newsletter no.18 "setting the neck angle" you recommended hollowing out the work board, instead of using a shim. My question is do you recommend hollowing out the WB for each instrument? Or is close good enough?

Oh, I see. Sorry.

You have a choice of hollowing out the workboard or placing a workboard shim on top of a flat workboard in order to allow the arched top (flat top arched by the braces, that is) to sit flat on it. This insures that the glue seams between the top braces and the soundboard aren't stressed when you glue the guitar sides down onto the perimeter of the soundboard.

The only requisite for the amount of dish on the workboard is that there be sufficient clearance for the "belly" of the soundboard. Yes, a perfect match would be ideal, but that isn't really isn't as practical as hollowing it out a bit more than necessary, and making sure that the only the rim of the soundboard is touching the flat face of the workboard all around. In this case, you'll have to be careful that the workboard shoe is kept from pushing the arched braces into the too-deep dished out portion, by the judicious placing of small shims under the soundboard (like my book describes) in the region just beneath the shoe. If the shim is insufficient, when you tighten the shoe, it will distort the soundboard and the headblock will tip back towards the soundhole. You'll want to shim it until you can snug it down without tipping the headblock. This goes equally if you're using a work board shim instead of hollowing out the work board.

The ol' binding mortise problem

I just finished a guitar based on your book. It came out really nice. The only problem I had was routing the binding ledge and purfling channel on the back. I just couldn't keep the cutter perpendicular to the sides, due to the back's arch. What is a good tool to use for this? Is it best to use a purfling cutter or grammil? [ed. European, I think, for Dremel router] I realize these things take a lot of practice but there must be a way to achieve perfect ledges and channels on the back.

Yes. THAT problem. The router cuts shy when it tries to handle parts of the back that are not perpendicular to the sides. It's an eternally thorny problem with no simple or easy solution, I'm afraid. I think you must have skipped over Step 2, page 248 in my book, which describes in considerable detail how you must subsequently deepen the purfling and binding ledges (wherever the router cuts shy) with a chisel after marking the limits accurately with a purfling cutter. You don't cut anything with the purfling cutter in my method; you just scribe a deep line on the wood that will serve as a limit guide for the chisel. This method works quite well if the purfling cutter and your chisel are very sharp, but makes a mess of things if they are dull. If you can't get things sharp enough to do a good job, you might try the small purfling attachment for the Dremel roto-tool sold by Stewart MacDonald Guitar Shop Supply, but that limits your purfling options to the guide size that is available.  Lately I've been actually routing freehand right up to the scribed guide line. It takes a lot of nerve and a very steady hand.

Short of that, there are also a host of gadgets and devices that Luthier's Mercantile and Stewart MacDonald sells to help you with the Binding Mortise Problem, some very clever, some very expensive. One or more might work for you, but each has its own kink or problem that you have to learn how to work around, anyway. So I stick to my own imperfect method.

My rosewood curled up!

I resawed a plank of cocobolo into four sections, and then the two outside sections for both the back plates and the sides have bowed something fierce. I have lost two of the sides to cracking, and I believe I have lost one section of the back to a crack that I can't see, but can feel when I put a slight bending pressure on the plate.

The Maccassar Ebony that I resawed for the fret board has also bowed (cupped actually) as well. It is incredibly frustrating! Is there anyway to salvage a bowed back plate? I was considering letting it soak in hot water and then trying to press it under some weight and let it dry. Same theory as the bending, I figured. I keep all the wood in my house, upstairs, where you can see I work, but it isn't great climate control. As always, I appreciate your help,

Alas, Guitarmaking is a strict teacher!

The problem you describe is a sign that the board was improperly kiln dried. Not insufficiently--but badly--kiln-dried. It's called "case-hardening" when its been dried too quickly on the outside, before the damp inside can dry properly. So the plank has moist innards and a dry outside "skin". After you saw it up, the two outside slices then have a dry face and a wet face, forcing a dramatic cup. A dramatic color difference between the two faces also, I suspect. What was the wood's source? --You might have an issue with the supplier.

This happened to me with a pile of Brazilian rosewood planks. The inner slices were approximately as damp on both faces, --and remained fairly stable--but the outside ones started to curl almost immediately. I laid the problem slices on the table, damp side down, and laid soaking wet rags on the (drier) outside faces and kept them like that overnight. By the next day they had flattened out reasonably well all by themselves, long enough to send them through my abrasive planer, and removed some of the dryer outside surface. Luckily the slices were thick enough. Then I stickered them (separated them with sticks of equal thickness placed one directly above the other--to let air circulate freely between them) and put them under cinder blocks and left them for several weeks to ventilate. When I removed the weight, they remained reasonably flat, but began to curl slightly hours later. So I restickered them weighted them, and pondered my next move. I struck upon a solution that saved the day: I had access to a large heated platen press like the ones that picture framers use to adhere photographs to stiff backing sheets. It allowed me to "iron" the plates flat. It worked like a charm. You'll have to find your own. They're still flat.

Lattice bracing

I have a few questions about lattice bracing. I remember we talked briefly about it a couple months ago over the phone. I think I remember you saying that you had made some classical guitars with lattice bracing. It seems like a great advancement, and something to consider along with traditional fan bracing for classical guitars. I understand the volume is increased. There usually is something lost when something is gained, so I was curious about what is lost - even tonal balance, familiar classical timbre?

It's almost impossible to make general statements about what "is" lost or gained, since it's so hard to pin down changes in sound to their precise source. The acoustic phenomena occurring on guitars are invisible; so most affirmations of cause and effect have always to be taken with a bit of skepticism.

But the instruments I have made with lattice bracing seem to be very even in response, which I suppose stands to reason because the soundboard is a much more "homogeneous" field with a grid of similar sized braces, as opposed to the traditional configuration of large and small braces angled all which ways.

The increase in volume is not a strictly expected thing; it depends on many other factors. The reputation of great volume- increases in lattice brace designs on classic guitars occurs in the presence of other radical design changes that are usually present in the best known examples: massively stiff sides, paper thin tops, low mass bridges, individual saddle posts and all kinds of non traditional features as found on the Greg Smallman instruments and all those that build like him. My colleague Alan Chapman is a lattice bracing adherent and his instruments are remarkably loud. But [sorry, Alan] they're a bit cold and uninviting to my ear. I guess you might say they have a lonely and cavernous sound, as opposed to warm and intimate. Aah, I'm probably just jealous he makes them so loud..!.

Our experience (my partner, Harry, has built several in our shop) with lattice on steel string, on the other hand has been excellent so far. The several he's made that way end up with an amazingly clean and precise sound, perfect for cool jazz--but maybe not biting enough for say, blues or ragtime. But then again, it depends on the musician to pull his or her own sound from the things, doesn't it? In the end all that matters is that it satisfies on some mysterious level. And each person responds differently. So the builder has no recourse but to pursue what satisfies him/her and hope that others agree.

Is anybody using this system for non-classical guitars for more than just experimental, esoteric designs? Steel string, for example.

Well myself for one. We're still experimenting, but luckily all our experiments have yielded satisfying results. I can't tell you that I have made any world-class knockouts yet with lattices. Just a series of satisfying, playable and inspiring (i.,e. fun to play) instruments. As any beginner, my tendency has been to work a bit too heavily at the beginning, so my early results were a bit hushed, but as I've loosened up the top by making the top itself thinner and the lattice brace cross sections smaller, the results
have been, to my ear and to others, better and better.

What kind of carbon material is used and is it always used in the lattice system?

We don't use carbon fiber in my lattices. We use just spruce or cedar braces, notched accurately. I haven't done graphite-enhanced braces. So no, its not ALWAYS used. You should remember this is a tinkerer's field right now, and people have been trying this new system for not more than seven or eight years max. I've seen/heard of half a dozen different uses of CF. I've seen thin strips of compression molded carbon fiber sandwiched between spruce walls to form braces, sometimes balsa. Others smooth epoxy-saturated fiber over the tops of the braces, like a cap over them. Every experimenter will give you their own rationale for doing what they're doing, usually non-scientific. This is not happening on an engineering level. Its happening on a tinkerer's level...and don't let anyone bs you about that.

Is it always sandwiched between wood? I have read where people seem to always use balsa wood to sandwich the carbon. Can you use spruce or does the wood contribute no strength, and therefore, people use the lightest wood available? Could you use spruce or are you really trying to reduce the weight that much?

The people that use balsa are relying on it simply to keep the CF center lamination straight and upright, without adding as little extra inertial mass as possible--thus the balsa. So the wood stiffness is considered neglible, since the graphite is so far superior in stiffness vs. cross-section. But remember that the stiffness to weight ratio of graphite is not as good as in well selected and cut spruce. So if weight is their preoccupation, there's a contradiction here.

How do you get it into the lattice framework? I am not aware of the price of carbon fiber - it is probably quite expensive, if not - why not cut out the squares/diamond shapes from the entire large "sandwich" of wood\carbon fiber\wood. It would seem to be much stronger than cutting strips from the large "sandwich" making in essence individual bracings and then have to interlock these bracing strips together.

Carbon fiber is indeed expensive, as it is difficult to work with, and hard to obtain for the average luthier. Most luthiers I know that work with it buy small beams of it from luthier supply houses and their experiments are limited to what they can get. What's so outstanding in carbon fiber is its beam strength. It is rather flexible in thin sheets, but if you cut strips from sheets and keep them upright like beams (and keep them straight) they are enormously strong, similar to aluminum, I believe. That's why most experiments nowadays are simply reinforcing a soundboard plate with graphite-laminated beams.

I was hoping to find a place to get plans for the lattice bracing system. Are they available anywhere?

No. There isn't a "set" pattern. Every builder that uses it simply devises their own flavor and sets out to find out, using their own intuition, by themselves.

Have you had any of your tutored students request that you help them construct a lattice braced guitar - or is this beyond the beginners abilities?

No, no one has asked me yet, but it is no more complicated--indeed probably less complicated to make a lattice top--at least the way we've been making them--than a traditional one. The only tricky thing is the precision required to notch the stringers so the array fits together snuggly and accurately. So a table saw fixture has to be made up for each distinct pattern.

Guitar bowls

I've been working on an idea for an acoustic guitar for the past 5 years, and have only now been able to have the means of creating my dream. I've run into a problem, though, with the bottom of the guitar. I wrote to Martin Koch, a luthier who recommended I write to you. The bottom of the guitar is curved, similar to Kaman's Ovation. I believe they use some kind of graphite composite, but I'm not really sure. The questions I have are these:

What kind of composite would be best for such a molded backing? Where could i get such material? and, what would be the best way of creating the shell? I would truly appreciate any sort of insight towards the finish of my guitar.

My good friends at the Ovation Company have told me bowl is molded fiberglass, each made in it's own mold that each cost hundreds of thousands of dollars. The molds must be precisely heated, so some have steam passages inside. Of course, each has to last through the molding of hundreds of thousands of bowls. If I were somehow required to make a single one, I would study the technique of laying up fiberglass shapes over a solid (wooden) form, like makers of surfboards do. They cut fiberglass strips and place them in layers on top of a form with fiberglass adhesive between the layers. The finished surface is rough, but when all is dry, they put fillers over it to make a smooth outer surface. A messy, nasty job, indeed--and all the materials are quite toxic. You can also look at the way lute makers make their bowls. It may be a more reasonable solution, although not as strong.

Function of the truss rod

I do not fully understand the function of the truss rod. Could you please explain its purpose?

A truss rod simply stiffens the neck to prevent or slow down the distorting effect of string tension. Now an ADJUSTABLE truss rod bends the neck back in a curve that is more or less in the opposite direction of the curve that the string tension imparts on it, and this counter-tension can be adjusted to allow the tension to draw the neck up into a controlled degree which will match the curvature of the string excursion (or shape the string takes when its vibrating). When adjusted correctly, the strings can be set lower to the fingerboard without buzzing than it could otherwise be set with a perfectly straight neck.

Feiten, Shmeiten...

What is your opinion of the Buzz Feiten tuning system

I'm just not a good information source on the Feiten tuning system, because I have until now resisted the urge to spend big bucks to find out how to fix something that isn't really broken. But recently somebody who took the course gave me the lowdown: Regardless of what the Feiten website says (that the traditional system is terrible, that the Feiten system is a revolutionary breakthrough that is wonderful) the truth is that the traditional system, (and we both agreed on this) when done precisely, is "80% accurate" and the Feiten system improves it to 90%. So without doing it myself (I'd have to take the course), the inside poop is that it is indeed a itty-bit better. But that's hearsay. Oh, and it costs $300 to retrofit your acoustic to it. By the way, last I heard Feiten is in litigation with Paul Reed Smith who claims he did it first.

"...it is indeed a bit better." seems to be the consensus gathered from several sources. I also talked to Peterson Strobe about the Feiten system and tempered tuning in general. They had this to say (my questions marked with >):
> ">Do you think tempered tuning for a guitar makes a
> >noticeable and practical difference on any guitar?

> Perfect beat-free intervals on the entire fretboard seems to be the holy grail among guitarists. These systems do make a difference, how much depends on the aural sensibilities of the musician/listener and the skill of the luthier/ technician/ retrofitter.
> > Do you have an opinion about using tempered tuning alone
> >vs. modifying the guitar to a system like the Feiten system?

> There are two choices:
> 1.Improve/modify the tuning
> 2.Stucturally modify the instrument.

> Both have their virtues, however even after doing 2. you will still be a long way from the "holy grail" Our opinion is as follows: If you can improve the situation through narrowing the intonation/tuning accuracy factor, you have gone a long way without permanently (structurally) changing an otherwise treasured instrument. If this is still not enough, structurally changing the instrument may, depending on the system, improve things marginally. In tuner terms we are very skeptical of any system which promises improvements by making structural changes and thereafter tuning with a common non-strobe tuner. If accuracy is what you're after then only the most accurate equipment will suffice, seems logical, yet people are sometimes very gullible when promised that what they've always

I don't know about this "holy grail" thing. I get really turned off when I hear about people searching for holy grails. Millions of people have been making awesome music for centuries on the most rustic folk instruments. The search for theoretical perfection bores me.

Absolutely! The first thing I thought when I heard about the Feiten system is "maybe this really is something" and then I thought "Wait, I've heard a lot of great music that wasn't played on perfect instruments with perfect technique..."

Do you know that you can make a note play flat OR sharp by how you press it down to the fret? Try it. Press a string down to a fret watching the needle on a tuning standard or the lights on a strobe. Now, while still pressing down, slide your fretting finger towards the fret (i.e., towards the bridge). The pitch will DROP (you can actually cause  the vibrating portion of the string to drop in tension!). Press down harder or slide your fretting finger towards the nut. The pitch will rise. This effect is particularly dramatic with the thicker strings, because your calluses can get a real good purchase on them. So don't tell me about 1/64th-inch notches on the saddle.

I just tried it and there is much more variation than I expected. Maybe players should pay more attention to technique than patents?

Your playing technique easily messes up the three-one-hundredth-of-a-semitone temperings that the Feiten system calls for!

Don't try this.

I have your book and have used it to build my first classic guitar, which turned out well. What do you think of the idea of using the Spanish style of neck to body attachment for a steel string? Do you think it would be strong enough? Of course, I would make everything else in the traditional steel string way.

Not a good idea. The steel string is under about twice the tension stress than the nylon string guitar, and the thoughtful builder uses a two piece construction that permits neck removal in the future for angle resetting if the neck is pulled up by string tension several years down the road. The earliest Gurian steel string guitars (built at the shop where I first learned my trade) were built this way. As soon as several started coming back requiring neck resets, I presume, he stopped making them that way.

What do I do now, Unca Bill?

I am part way through my first instrument (a Dreadnaught Herringbone) - the back and sides are rosewood and the top Engleman spruce. All was going well until I glued the back bracing. On removing the cam clamps from the braces I noticed to my horror a hairline crack about 1" off centre that runs almost the whole length. My question is - can this be repaired or is the back now destined for the scrap bin?

The braced back is still off the guitar, right? Carve off the braces, flex the plate gently to see if it completes popping apart. If it doesn't pop apart leave it together. Apply thin super-glue (crazy glue, cyanoacrylate) along the crack, put the back on a flat surface, place some massive weights on the back on either side of the crack to make sure they lay flat along the length of the seam, and push the plate halves together and aligned before the glue sets. Two clamped-down blocks beside the back on either side, with little wedges tapped in between will squeeze the halves together handily. So you don't glue the thing to the table, do everything on top of some newsprint paper that you can scrape off later. You have about 30 seconds, so do a dry run first to get your movements fluid. Scrape and sand. Rebrace. Good as new. Next time scrutinize all your plates meticulously before assembly.

No need to be meticulous here

I'm midway through my second guitar from your fabulous book, and in the planning stages of the second. But I've run into a problem, since I can't locate plans for this model: how does one determine where to put the tone bars? To be more specific: I'm planning a Gibson J-185. I know the plantilla, dimensions, soundhole size and location: everything observable from the outside. I also know that the 185 uses a single 103-degree X-brace 1" below the soundhole, and twin tone bars at 61 degrees. But that's all. So where do the tone bars go, i.e. how far along the treble leg of the cross-brace do they begin? What about the fingers?

I'm afraid I don't know the Gibson J-185 bracing pattern by heart. I don't believe that the precise brace locations are crucial, anyway--as I comment in my book. I recommend that you extrapolate their locations from what you know already.

If you're going to be a fanatic about their precise location, the only thing to do is to obtain a J-185, and shine a light inside it through the top in a dark room and trace it through the top. But you've got to obtain one first. Good luck! No, there is no database of guitar bracing patterns on the internet, or anywhere else, for that matter. The Guild of American Luthiers has a collection of bracing plans for sale, but the collection is far from complete. Sorry.

"Mineral-stained" Rosewood

I am working on my 3rd guitar based on your book. It's been a great help. I especially like your new neck design. Anyway, I have some mineral staining on the rosewood back set of my most recent guitar. Do you have any suggestions as to how to remove the staining?

I'm not sure what you mean exactly by "mineral staining." Do you mean a generalized black color over the entire plate (rosewood stored underwater gets mineralizes to a deep black), or just deep, black inky blotches surrounding small (insect) holes? or just hazy greyed-out discolorations?

Rosewood is prone to pigment staining because the logs lay around in the forest after they are cut for long periods during which the logs get degraded a lot. Some of that "degradation" actually results in some of the beautiful sworly, inky patterns that are so prized in the wood.

The only remedy for discoloration, frankly I don't wish on anybody. It involves soaking and repeated washings in a caustic bleach solution, which leaches all the brown and black out, leaving the figure behind. It leaves the plates an even, ashen gray but with the typical rosewood line pattern. The wood is left to dry out thoroughly, and then the guitar is built from it. During the finishing steps, rosewood-brown tints are sprayed on the surface, and the once-mottled and disuniform colors are transformed to an even color. Quite beautiful, actually, and you wouldn't know that it wasn't natural.

Martin Guitars did this with a run of Brazilian rosewood guitars. It happens they received a truckload of Brazilian that had been underwater for a long time, and it had mineralized to a jet black color. Otherwise it was both beautiful and still precious. Well, they didn't want it black, they wanted it brown. So they bleached it in the way described above.

It caused me to go nuts, though, because I had to do a splice repair on one of them, and when I leveled the surface of the splice with the surrounding wood, I burned through the tissue-thin bleached-out area, exposing the jet black below. so the area around the splice turned jet black!!!. I had to find the crusty old Martin finisher who had actually worked on the finish of that guitar (he had retired since) and talk him into re bleaching and refinishing the back for me at my expense. So don't bleach rosewood. Live with the blotches. Or put it aside for an expert finisher to deal with. Take a tip from me: there are consequences.

Roping Material Update

The back-roping elastic strip that I still use dates to my earliest guitarmaking efforts (circa 1969), so I suggested in my book that people cut them from the same source I used: automobile inner tubes. Today, thirty years later, you might find an automobile inner tube in a car museum, but certainly not in a parts store. So what can I suggest to my present day students?  Well I've had some correspondents suggest some excellent alternatives. It appears that trucks still use inner tubes, so those would do, providing you account for their thicker gauge by slitting them thinner than what was recommended in my book. Here are some other recommendations sent by other helpful correspondents:

"I ride a bicycle and have saved many inner tubes that I am now using on my second home built guitar, (an all mahogany steel string for my son.) Check with your local bike shops to see what they do with the flats that they repair? Your book has been an inspiration. "


"I found an excellent source of rubber rope from the Physical Therapy field. It is marketed under the name Thera-Band, or Cando, it is low powder latex rubber that comes in rolls 6"X 6yds It also comes in different thicknesses and tensions. You'll probably want to get the heavy or extra heavy stuff. It runs from $8-15, a good source is www.wisdomking.com, but I
imagine you could get some through a Physical Therapist."

Beginner's Mind

I have always been interested in building acoustic guitars. As I am of the character of jump first, look later, I plunged head deep and built two guitars without consulting any sources other than trying to copy the one Martin guitar that I owned. The results were, as I am sure you are guessing, atrocious! Even so, I have never had such joy for the process of making something
of which turned out to be so awful. At the end, I turned to sources to see specifically where I veered off course. A local luthier was helpful in critiquing my works but not interested in how to do better.
     I then went to the printed word and, after several disappointments, was fortunate to find your and Mr. Natelson's work, Guitarmaking: Tradition and Technology. A tremendous work indeed! But with the foreboding knowledge of my complete ineptitude, I lacked the courage to try again even with the help of your worthy book. I wanted (read, needed) to get some firsthand instruction. The idea of learning from a professional, however, led me to want to pursue the field with more vigor than a passing hobby. I would enjoy immensely, I believe, taking up the art as my labor of life. This may, I'm sure, seem most over excitable to you for there are many that think they love something without the knowledge of what it truly is or what is asks of you. Nevertheless, I have decided upon a path and will not let others' objections lead me astray. This has brought me, albeit in a very slow and meandering way, to the nature of this letter to you. I am sure that your classes would be most welcome and challenging, but I am wondering if there is a longer length of course offered? On your website, you mention your art takes many a year to become proficient. How then does one proceed after your six weeks of instruction?

I'd be either silly or devious to claim that six weeks in my shop is going to turn you into a world-class luthier. I can claim that it will leave you with a lot of knowledge, the knowledge that it would otherwise take you years--and many painful mistakes--to discover on your own. Years of knowledge, but only six weeks of experience. But what more can any teacher offer? I suppose you could take an additional two weeks, where you learn to design and assemble an altogether different kind of guitar. But remember, you'll have to provide $40 an hour for tuition, no less than $60 a day for room and board, travel and materials. That adds up very fast.

The experience portion you'll have to supply after you leave, by working to re-order your life so you can devote yourself single-mindedly to doing this over and over until the medium becomes familiar to your hands and to your mind. The challenge is to somehow provide yourself the time and environment that is adequate to do this. Only you can provide that. You'll have to find some way to provide for yourself in the interim. Unless of course, you have the privilege of the means.

The second learning phase, as important as the one I've just described is the economics of guitarmaking. Your success as a merchant of your guitars is at the same level of importance as your success as a builder of guitars. You have to succeed at both. You can't just succeed at one. Guitarmaking economics also is a series of strategies that you have to discover for yourself, strategies that fit your personal style and environment.

What I CAN provide you while you're here is an environment where most of the problems of sequence and organization have been worked out: a model of a successful small guitar making operation that is available for your scrutiny. An opportunity to watch an experienced maker handling the tools and materials in a manner that consistently produces desirable results.

Would one try to get an apprenticeship with some master at that time? Or should he attempt some years on his own before asking of the honor?

Honor? Please, forget about that romanticized Stradivarius/ Gepetto's apprentice fantasy! You apparently have fallen into the common movie illusion that there still exists some kind of a guild system that disappeared for many good reasons two hundred years ago. The reality is that very few professional luthiers are looking for apprentices--that is, people that help maintain their shop in return for the privilege of not being thrown out. They get in the way. They are distracting. They get hurt and sue. And besides it only takes twenty minutes to tidy up a luthier's shop. I've had two apprentices in thirty years. One was an ex-clockmaker that knew how to create spectacular jigs and could sculpt a fly on the tip of a toothpick. The other was a CPA who to this day takes care of all my taxes and financial matters for free. Do you have any such spectacularly useful skill that would make a professional luthier beg for your extended company? If not, forget the apprentice thing, unless you are unusually lucky or unbelievably talented.

The other illusion is that a factory is a place to learn guitarmaking. They don't want luthiers, they want machine operators. I know whereof I speak in this regard.

Or are there other schools that would be enlightening in the interim? Or maybe, simply, I should just seek to enroll in your classes and endeavor to let my feet find their own path afterwards.

I can't see any other way for a career-oriented prospective luthier: a school with eight other students (expensive), or one-on-one with me (very expensive) or my book (very inexpensive).

I hope you can see I am singularly interested in moving forward with my goal but seem incapable of finding anyone with definite answers on how to do so.

Hope the above helps.

One last note of little consequence: I was especially pleased to see your reference to and elucidation of "the beginner's mind" in one of the newsletters on your website, for I have done no small work of my own into the philosophy of our Eastern neighbors. I have completed several degrees, one of which is in Chinese philosophy, and am now, quite unofficially though, working on a doctoral thesis into the great Taoists, Lao-Tzu and Chuang-tze; both of whom are particularly associated with this wonderful idea.

My work partner of many years, Harry, is a very knowledgeable dilettante in a similar field. He has done a lot of personal research into Mandalas and can talk for hours about them. And Brazilian guitar music.

Minimal resawing resources

As a luthier wannabe with bigger ideas than budget, I like to pick up cast-off hardwoods. Some of these are possibilities as tone woods. The problem is, resawing them into useful thickness for sticking and planing. I've read a bit, and even tried to cut a few, with miserable results. I have researched the cost of bandsaws that are specifically designed for resawing, and even the ones that aren't particularly good, with 3" blades, etc., the cost ($2,500.00) is overwhelming. A friend of mine owns a specialty wood floor milling company -- his 5" blade German resaw cost him $12,500 used! I can travel to his shop and use his, but would rather be more self-sufficient. Are there jigs, and set-up specs, or ideas from your long experience to guide me in adapting a more affordable bandsaw to resawing duty? I've checked most of the forums -- ASIA, Guild, MIMF, and haven't really found any solid advice. I'm not even sure what to look for in a band saw. Knowing your work load is pretty heavy, I'm not in any hurry to hear from you. Any response would be a blessing.

I've been using a 14" Rockwell/Delta bandsaw with a 6" riser block with a 1hp. motor and 3/4 raker-set hook tooth 3tpi blade and replacement Carter guides for 20 years (cost: under $1000) and it has admirably done the job for me. Slow? yes. Blade Life? Not so great. But with careful setup, I feel confident to cut 1/8 (or even less) slices of Brazillian Rosewood, removing about .06 of kerf waste, all with a smooth, even, tooth pattern on the
surface. What would I do to improve it? Get a 2hp motor to solve the slowness. Hit it rich and get the saws you describe--but they wouldn't fit into my shop.

For modest production resawing, you don't need an expensive saw. Just the right blade, enough power, good guides, and enough height clearance to saw guitar backs. And a bit of patience. The saws you mention are production
saws for small factories.