Official Luthiers Forum!

Here's what I have:


What this told me was I could not use the drawings from which to scale anything. If the drawing had all the necessary dimensions, this would not be an issue. I always refer to the dimensions first but if they don't exist, then have to scale the drawing or engineer it yourself.

I think we can all agree that the critical dimensions are the ones that relate to the scale. You have to know where the nut goes and where to break the angled headstock from the plane of the neck. They have to be accurate.

As I was marking up the neck blank, I needed to know where to mark the point where the headstock angles away from the plane of the neck. That dimension does not exist on the Antes plan. So all you have left is to scale it. But the plan isn't accurately scaled. That makes the plan useless for creating the neck.

I use AutoCAD for all my drawings and it makes pinpoint accuracy easy. So maybe my expectations are high. But if you can't create accurately scaled drawings because the program doesn't allow it, shouldn't we at least expect the drafter or engineer to make sure all critical dimensions are clearly stated on the drawings?

_________________
Julie Moriarty
http://JulimorCreations.com

I can imagine that after paying money for plans that sure look like engineering type plans, incorrect measurements would be disappointing. I remember when the Ibex ruler came out, and it had some significant errors, that I did not catch because I trusted the ruler. Since then, I measure myself.

So regardless of printing error, humidity, or that the initial drawing was incorrect, even if it were correct, I would not use a plan as-is; I draw my own, using the plan as a guide, for several reasons. But I don't regard the plan as a waste of money, it gives my a very good guide, the shape of the plantilla, and brace placement, etc. I have the same OM plans, because I am building one for my daughter. I never even thought to check the fret distances because for me at least, it is irrelevant - just because the plan uses a certain scale length doesn't mean I have to. If I were to build a slavish copy, I might as well just buy my daughter an OM and go on to building the other guitars that I am waiting to build. It has always seemed to me that the benefit of a handmade guitar is that it is tailored to the buyer (or at least, that is what my customers say). So, my daughter's guitar is going to have a 12 fret neck on an OM, to take advantage of the compressed upper bout, to get the bridge even more centered on the lower bout than is possible on a 000 style guitar. But, I am copying the shape, the measurement of the X-brace relative to the bridge wings, side thickness, etc.

As to the reasons, when I started out in the seventies, I had to draw my own plans from borrowed guitars, so I got used to drawing plans. I never drew the fret positions on the plan though, just the nut, the 12th (or 14th) fret, the last (highest) fret, and the bridge string spacing. By drawing my own plan, I get to sort of build the guitar on paper, and make sure I can visualize everything and that it would work. Another reason, is that I record the details of a particular build, or change in a build very accurately. I have successive plans of my version of a 1943 Hauser, with ongoing changes and notes. For a series of guitars, I just knock out a plan, and put all my notes on it.

When I am building the guitar, again, to rough out the fretboard, I am only interested in the taper and total length, relative to the nut, 12th fret, and the last fret. I cut my fret slots after the fret board is glued on, the board is surfaced, and shaped. Then, if I don't have a template (I use a 3/4" square aluminum bar with scribed fret lines), I use an 18" digital caliper, and measure the fret positions.

thomLuth you brought up a few valid points.
Many may assume martin had blue prints from the beginning but in fact did not. They didn't have blue prints of anything until the 70's when Dick Boak came into the scene. He once said the first blue print drawn was of the neck block. Up to this point everything was determined by patterns and jigs along with foreman's notes.
Also in all fairness to those that may have drawn a plan off an older Martin guitar. In many instances they themselves are different so you may have an accurate plan drawn off a guitar that was made in a fixture #A that was different by a fraction in fixture #b
You are correct in using a purchased plan as a reference and draw one to your shape and make it accurate for your purpose .

The point of my post was don't ever assume purchased plans are correct. There are many reasons that they may be different. Always use the numbers and refer to the notes in the block

I hope I gave you something to think about to help make you a better builder

_________________
John Hall
blues creek guitars
Authorized CF Martin Repair
Co President of ASIA
You Don't know what you don't know until you know it

Julie, there are several things going on here.

First, Martin's scale length is traditionally 25.34 inches but we frequently round it up to 25.4. Antes specifically gives his as 25.400 - that can introduce some error. (John Hall would be a good person to talk about the history of Martin scale). Note that your scale is 25.34.

Second, there are at least three different methods of mathematically calculating the positions of frets on our "even tempered" fretboards - the 12th root of 2, the so called "rule of 18" and, admitting that the rule of 18 is slightly off so people use 17.817 - it is usually considered close enough for what we are doing.

Next, our "even tempered" fret spacing is by definition a compromise. Lots of wonderful articles out there on this subject.

Lastly, the mechanical properties of strings mean they don't follow perfect mathematical predictions. We therefore compensate our guitar's geometry to make it more acceptable. Usually this is done by moving the endpoint of the string at the saddle. Some people move the endpoint at the nut also - when this is done frequently the first few frets are also moved.

Here is my little OM built from the plans in question. The fretboard is a preslotted unit from LMII - I don't know how they jig the boards to cut the slots but I assume it is with some sort of template similar to yours (probably doesn't say StewMac on it). It is in theory slotted to 25.4 scale, I confirmed that the 12th fret was at 12.,70, thats all I checked. The saddle slot was located using the StewMac calculator, the guitar has generic compensation and plays within +/- 2 cents on all strings (measured with a strobe tuner). Thats good enough for my old ears.

Here is the same drawing on the fretboard of that guitar butted up against the nut. You could argue that there is some variation between the drawing and frets, it might be parallax, it might be significant. I'll argue that its pretty darn close





I also want to add that I don't have a dog in this fight. I have built guitars from Antes OM and parlor plans, I think they are pretty darn good guitars. The parlor plans have a significant flaw that LMI should correct (at least with a sticker on them) - they are drawn as tho you were looking thru the top rather from the back as is industry standard. That means its pretty easy to build a lefty. The other big complaint about all of the Antes plans is that they are heavily braced. That is fine for someone's first guitar or maybe a production situation, one of the things we learn in our path toward lutherie is how lightly we can build something and still have the structure we need. Whole books have been written on this subject.

I'll add that I too used Autocadd and SolidWorks for all of my computer drafting, but I have a solid base in mechanical drawing with a pencil, and I come from a shop environment where these drawings were used to produce real things. Before I retired while I still had use of some of the big cnc machines (particularly a laser cutter) I made a bunch of different jigs and fixtures - radius templates and drilling jigs and all sorts of neat little things - draw them in Autocadd and dfx a file out to the laser. If you doubt the accuracy of commercial plans that is an option for you.

Jules, Looking at your picture your Martin fret scale is at 25.34. That is different than 25.4 or 25.5 and I am not sure what the Antes plan is using because I haven't used it for some time. You should factor that in, decide which you are working with, and make sure that they all are the same. Same with the short scale, 24.9 is different than 25.

Laying the print, if to scale, over the fretboard may tell you if you were way off relative to your print. You still need to measure it to know exactly where you are and go by the given dimensions and tolerances. If you can't measure it you can't really make it to the plans anyway. A print is not a measuring tool.

The difference between 25.34 (Julie's rule) and 25.400 (Antes plans) is about 0.004 at the first fret and 0.042 at the 20th. The saddle moves 0.061. Obviously one would locate the saddle slot based on the actual scale plus their desired compensation.

That looks to be close to the deviation she is showing in the picture

so what is the comment about the Ibex rule having errors! What are they? can anyone elaborate please? Bob

I think a lot of this situation has to do with expectations...and of course the average Joe is going to expect a print to be very accurate...I note that at LMI the word "plan" is used in regards to the Antes products, and the word "print" is used with their herringbone plane...say what? are they playing word games in that the herringbone is accurate and the Antes are not? if so, that is complete chicanery, and I don't care how long they've been in business...I note that at SM their herringbone plan is described as "full -scale"...huh...now just what does that mean (it surely implies a high degree of accuracy)

let's skip all that, and I'll just state that if a plan/print/whatever is NOT to scale it should be advertised as such, end of discussion.

my years of experience in the trades give me 2 concepts on this subject:

1: I'm used to seeing "not to scale" when that is the case (e.g. the rest of the prints are assumed to be at scale)

2: even "at scale" I rarely trust them to anything lower than an inch of accuracy for various reasons learned the hard way

let's take another view of what is being discussed in this thread:

from my viewpoint, if something can't be drawn and printed out to an error of less than 1/32" there is a problem. and that problem lies on the supplier's end...to try and blame the end user for their expectations is just the action of a Snake Oil Salesman.

I will have to agree that trusting a print out from an outside source for the layout of frets is probably not a grand idea, and unless one has a high dollar (I assume) printer I wouldn't trust it either. there are fret scale templates and one can only hope those are highly accurate...either way, skipping the concept of fret layout, I'd hope that any plan/print for sale can be trusted to accurately layout every other part of the operation within an error margin that simple compensation can solve, any other result is a loser and should be called out

Mike, while I agree with your post I think the issue here is that these plans ARE accurate - if you wanted to scale them (or glue that fretboard plan on a piece of ebony and start slicing) your fretboard would be accurate 25.4 inch scale length. I argue against trying to scale any drawing where dimensions are given (and they are given in great detail on the drawing). Julie's SM rule and the drawing are different scale lengths - albeit not much, but different.

If Julie had posted that picture in her first post several of us would have pointed that out to her - that she can in fact build the guitar with either her scale or the drawing, both will work just fine. She might have to make some minor adjustments for the 25.34 scale. Julie also says "I also have plans by Kinkead and the scale is off on that plan, too. Who can you trust?" - Once again, the Kinkade plans (which I have in front of me right now) say very clearly "Scale length:25.4 in (645.2mm)", I trust them.

Julie may not understand that guitars can be built in a huge variety of scales and manufacturers often change (Gibson is notorious for this). Fret location is critical, that is why after mitering a few boards I decided to just buy them pre slotted. I build everything from mandolins to near baritone scales - making or buying all the templates would be a real expense and hassle. I also understand the limitations of our music system - fortunately my ears aren't that critical.

So maybe I can summarize some things here:

- understand what your drawing(plans, prints) represents
- always read the fine (and big) print on a drawing
- if dimensions are given on the drawing, use them
- understand the limits of trying to lift a dimension off of a drawing
- understand the limits of cutting wood to a certain dimension

We have available to us fret boards that are accurately slotted by reputable vendors, templates such as the ones that LMII sells, tabulated spacing lists from various sources and online calculators such as the one made available by StewMac. We have and use these because it's commonly understood that getting the nut and the frets and the saddle in the right places is crucial to good intonation, without which a fretted instrument is a mess not easily corrected. This being so, it's puzzling that anyone would jump to the conclusion that a builder is entitled to cut fret slots based upon an image that is printed on a piece of paper unless it explicitly says so or the vendor of the plans confirms after specific inquiry that the plans are intended to be relied upon in this way. With due respect to other disciplines that use drawings in one way or another and in which various conventions are followed, fret spacing is central to building fretted instruments and demands close attention. Failing to verify correct spacing on a drawing is a superficial approach to an exacting craft and isn't much different from slavishly copying the dimensions that a plan calls out for braces or top thickness. A builder who does any of these things might produce an excellent instrument, but only by chance.

It isn't reasonable to fault either Mr. Antes or LMI in this instance.

If people have learned anything in this post it is to check the print with the numbers.

I have a collection of prints and of those only a few are accurate to scale so please use the numbers for best result.

it is good to see people sharing information. Sometimes it is better to be lucky than good. Learning good sources is also valuable.

Learning to measure accurately and produce the parts to the print is a skill that takes practice

_________________
John Hall
blues creek guitars
Authorized CF Martin Repair
Co President of ASIA
You Don't know what you don't know until you know it

This was back in the late '70s or early '80s, and as I recall, the error was in the metric ruler in the first production run. I got mine when they first came out, but did not use it as a ruler, since I had access to much better and easier to read rules. My point, though, was not to bash Ibex or to cause alarm, but to highlight the need to check everything. From time to time, I check my measuring tool against each other, and straight edges on a granite plate. And like I said, I make my own fret templates, the way I originally learned.

Julie, to put this to bed how about doing a little experiment. You trust AutoCadd to be accurate, so do I. Start a drawing with a 2.188 inch long line (that happens to be Antes string spacing at the pins, you might want something different). Offset that line 1.4256 to one side. Offset it again at 2.7712 to the same side. Again at 4.0412, again at 5.2400, again at (you can read the numbers off the upper right corner of your plans). Offset it at 17.3995, that will be fret 20. Do one at 25.400 - that is the scale length. Now do two more, one at 25.489 and one at 25.614 - these are the ends of the center line of the compensated saddle slot for the high and low E strings. Connect those two points - it will be a diagonal line representing the saddle slot.

Now plot this 1:1 scale on what ever kind of plotting device you use. Take it to your Antes drawing an lay it over the fretboard plan - fold it in half down the center line, take a picture and post it here. Take it to the body plan on the right side of the drawing, lay the line offset 14.0856 on the top of the body directly over the outside line and see where that little angled portion falls. It should be pretty darn close to where the bridge is drawn. Take some sort of picture and publish it too.

My plans have a penciled line across the bridge and the note " scale length - 11.3144 from outside of body" (however when I actually did locate the bridge I worked from the nut just like your little Acad plot.

If you decide you want to make it 25.34 scale use the SM calculator to determine the offsets. You will still place the 14th fret on the top of the body, the head will move towards the body a bit, the bridge will move up. Decide if you need to alter the brace location or to splay the X, make sure the pin holes don't get too close to the X.

Report back

I've tried to read all this stuff, and just keep going back to my F5 Gilson days. I had print after print after print, most all of them claiming to be the real deal (maybe that's why I went with Larson guitars, there was no "real deal"). No one had any Larson information till the Gal print and who knows how accurate that is. Prewar Stellas and Larsons were known to vary, sometimes by quite a bit. I have no doubt Martins did too...
One of the old guys that worked at the Gilson plant way back in the '30's sent me a tracing of the F5 headstock and the A5 headstock also as I had a big conflict with one set of plans that, to me, showed a forshortened headstock as a planview. Much later I had a conversation with the guy that sold the plans and convinced him that the print was mistaken. He was and is a famous mandolin builder and aficionado. He changed the print.
Now, the old guy at Gilson told me that lots of jigs wore out, broke, pencils got dull, etc and dimensions changed like temperature.
When I decided to build Larson Guitars, there were no plans, nothing. I took frontal photos and enlarged them to a "thereabouts" size by the scale length when I knew it all the way to tuner spacings. I figured I could never be that far off.
When building guitars, I rarely relied on prints, plans or "engineering drawings". All you really need is the mold and a scale length.
Scale length will tell you exactly where to put the bridge. That's about all you need. The rest falls into place. A nice plan will show you approx. where to put the braces and you are off and running. What particular flavor (year) of guitar you are trying to emulate, if it is in the pre-computer age (or not!), is a crapshoot. One guy will tell you he played a '37 B25 and it was astounding...the next guy will tell you he played one and it sounded like garbage.
Buy a precut fingerboard from someone reputable or buy the miter box, saw and templates and get on with it...

Bill Lewis sold some plans from his store, Lewis Supply in Canada, which was later sold, I think, to Todd Taggart. I have a Ramirez plan he sold, which at least looks like a blue print. Back then the technology was too expensive to get nice plans. So the only way to use that plan, which was almost opaque, and writing on it was useless, was to redraw it, so it could be annotated and actually used. But my advice would be to do the same today, even with very well done plans.

Interesting you bring up Dick Boak. I met him at the GAL convention in Estes Park in 1982. He was very helpful in describing how Martin did it. He was also selling some of the tools that the Martin builders used. I bought a triangle fret file from him which I still use, on occasion. It is interesting, the current expectations, compared to then. Back then, other than a few books like David Young and Sloane, there was almost no information available, except to strike out on one's own, and learn from mistakes, or/and find someone building guitars. But the experienced builders were very accommodating. I dropped in on Charles Hoffman, and he graciously showed me his shop, the set-up in the basement of his store, where he did the dovetails and things, and really explained things. That was the case with several builders I visited. But in general, there was no opportunity to see how something was done until you did it yourself, like bending sides. Nowadays, we are literally swimming in books, online stuff, youtube videos, and classes. So, it is a great time to learn - you want to bend a side, there are numerous videos on-line showing all kinds of techniques.

You must be about the same vintage as me. When I started there was nothing but two or three books like Sloane...no internet. I had quite a bit of woodworking experience but learned a lot from a friend who was an architect and absolute master woodworker. He had built a couple of guitars of his own design and graciously let me into his shop and taught me what he knew.

just got my medicare card .
I think I came into the scene at a perfect time. In the late 90's the internet was starting to be more available. Kathy Matsushita was a great help. Frank Ford and Martin. I got to know so many people in this trade . I like to pay it forward. Some of my early drawings and prints are nothing like what is available today.

_________________
John Hall
blues creek guitars
Authorized CF Martin Repair
Co President of ASIA
You Don't know what you don't know until you know it

You're just a kid! I started building in the mid-sixties . I'll be 76 next month and am still learning and still fascinated by this obsession. Thank you for your excellent insights!

First post edited. Crow now being digested. I ASSUMED the Antes plan was for a Martin OM and used a 24.34 scale. No need to go why it's bad to ASSUME.

That being said, I still hold that the dimensions for the neck should have been included in the plan, as should all critical dimensions.

As for using drawings to locate frets, I've only had to do that once, for a Ric-style bass with a 33.25" scale. That was a bit nerve wracking because it was a thru-neck. But it intonates fine.

_________________
Julie Moriarty
http://JulimorCreations.com

no need for crow
you learned something that is more important
Ante when he drew up plans ( understand that Martin owns the ooo and OM design so he took some literary license)
I too used his plane early but have learned from making some of the same mistakes you did. MacRostie did a good plan
Best to you I am sure you will do well have fun building these boxes.

_________________
John Hall
blues creek guitars
Authorized CF Martin Repair
Co President of ASIA
You Don't know what you don't know until you know it

Julie, once again, the plans are specific that this is "similar to Martin(r) Orchestra Model". The scale is very specifically given. The Kinkade plans call it his own name, he doesn't reference OM at all. Again, the scale is spelled out in very large letters. Not only is it bad to assume, it isn't necessary.

The dimensions for the fret spacing are very clearly given. From you drafting experience they could have been dimensioned from the nut in base line form but that would have taken up a lot of drawing space. The little spread sheet is far better. Antes does give the length of the fretboard next to it, image 20 other 4 place numbers stacked along side.

I don't know how accurate it is to any one specific guitar but it is certainly complete and correct enough to build a very nice generic Orchestra Model guitar from . I know, I did.

In fact, as an engineer looking over these plans I'm pretty impressed. In you work with AutoCadd you could strive to emulate Antes work, particularly if you intend your plans to go into a production environment.

Where the mistake was made was all the rest of us ASSUMMED that Julie was correct. While she ranted about how incorrect they were the rest of us took that at her word and tried to explain why you should never scale a drawing or assume it is correct. No body stopped to check her assumptions until I put my little caliper on the frets (after explaining the limitation of their accuracy) and, bingo, the frets seemed fine. A check of two fretboards from two different sources confirmed, there is nothing wrong with the drawing. A picture of Julie's little scale and guess what, she had not read the information give to her on the drawing.

I just pulled out the StewMac drawing for their 000 for another forumite on another thread. It gives the scale as 25.34 and a nice little grid of all of the fret locations based on that scale. I'll bet if Julie put her little ruler along side the fretboard on the drawing it would match perfectly.

Lets let this thread die as it should and get back to the important task of building guitars

We might keep things open long enough to mention that there appears to be at least two possible, authentic scale lengths for an OM - the 25.340" (25.4" per Martin's site) modern scale, and what builder/vintage Martin repairman T.J. Thompson says is the prewar OM scale length of about 1/8" shorter. or around 25.25" or so. John Arnold is also said to have used a shorter scale length of about 25.315" on prewar instruments, but I was unable to locate the original UMGF posts by Mr. Arnold attesting to that information, so include it here with a desire that he might clarify the issue.

Just to sew further confusion and provide custom guitar builders and repair people more grist for the conversational mill, the Orchestra Model moniker appears to have been applied to all of the 14 fret-to-body Martins developed in the post-1929 time frame to differentiate those guitars from the 12 fret-to-neck versions already in production and using different body shapes. As late as 1957, Martin copywriters appeared to have used the term in the generic sense, but by the 1960s, the modern usage was in place, with Martin decreeing that the OM label only be applied to a long scale, 14 fret 000 body configuration with a 1-3/4" nut width...or apparently, whenever Mr. Mayer insists on calling his newest 000 model an OM-something-something-jay-emm.

For what it's worth, we fix the nut location after the preliminary neck fit (e.g., neck alignment with body centerline and neck angle), marking the final nut location only after the completed fretboard is dry-fitted...the peghead is planed back to the line which defines the nut face, the peghead veneer is glued in place, and trimming of the head stock to final plan view is accomplished. The back of the peghead is milled to reach the desired face-to-back thickness, the board is glued in place, excess wood outside the fretboard is trimmed off, and the neck is carved to final shape. We use a bridge plate location and width designed to accommodate some variance in neck fitting, so up to 1/16" of shift in the 14th fret relative to the body can be addressed without concern. The ability to fix the nut location to the nearest few thousandths of an inch prior to neck construction is not necessary using this approach.

_________________
For the times they are a changin'

- Bob Dylan

When one of the most respected sources in the industry says, "Martin 'long' scale is commonly referred to as 25.4" but measures 25.34", most would take that as fact. I certainly did. Why anyone creating a drawing based on Martin's OM guitar would deviate from that is beyond me.

Had Antes taken the time to provide dimensions for the neck, there would have been no concerns. Critical dimensions should always be noted. It should not be left to the purchaser of the plan to scale those critical dimensions. All it would have taken is a few extra minutes to note those dimensions before submitting his plan for sale. Antes instead states, "Dimensions not specified may be scaled."

As for Kinkead's plan, in the book in which the plan is included, it clearly states the guitar build in the book is inspired by the Martin OM model. He sings the praises of the OM model and makes it clear his book is based on that model.

_________________
Julie Moriarty
http://JulimorCreations.com

According to the Stew Mac fret template I have, the Martin "short" scale is 24.9". In Kinkead's book, as he discusses the history of the OM, he says three years after the introduction of the OM model, it was merged "with the 000, 14 fret neck series of guitars, which had a shorter scale length". The book does not say what that scale is. It does say, after the merge, the OM model wouldn't die and Martin finally resumed production of the OM.

_________________
Julie Moriarty
http://JulimorCreations.com