1956 D’Angelico New Yorker - 18.5” - Cutaway

[Archie]

Whist browsing Ebay a few nights ago, I came across some plans for a 1956 D’Angelico New Yorker, sold once upon a time by Luthiers Mercantile. The drawings were made by Tom Ribcecke and they were cheap (£15/$20), so I thought I'd have some fun.

The plans arrived a few days later, 2 x A1 'to scale' drawings. They were well worn but the scanner did a good job of flattening them out to produce an accurate digital image.

Here are the plans now digitised.



My first job was to bring the drawings to scale. I then put down some grid markings to help me align the drawing. This was the moment I would discover how accurate the plans were going to be and the answer is, not very.
This is the problem with CAD. When you have impossible accuracy, everything done by a human hand, is going to be out. The trick is knowing when to draw the line and how to see both views.

Below you can see that the outline of the body is not totally symmetric and the given centre line is actually off centre (by about 2mm/0.079")



Regardless I drew a new centre line and aligned my horizontal guides so that the body was straight and centred, as best it could be.

I then made an outline from splines (bendable lines) so I could start aligning the arched templates.




Now I start bringing in the arch guides, starting with the centre line.



Here’s the lowest one going on, I’ll work my way up from there. The drawings provide the placement of these guides so it's not random. You’ll notice the little lines to the side of the body outline.



The problem is the arching templates were either poorly drawn, or most likely, well drawn but showing the work of D’Angelico’s hand (or perhaps D’Aquisto’s)? The shape of the arch is all over the place and the thickness seems somewhat random; the arch is way off centre. There could be many reasons for this and so my job is to interpret what should be. You could copy what is exactly there but that would be like remaking the “leaning tower of Pisa” with the lean.




As I put each template down, I added a spline to trace the drawing or try to intemperate where needed. Perfect geometry is easier to produce in CAD than non perfect, so it's often good to let the programme do the work and more often than not, it reinterprets the original shape but slightly better (more symmetry, smoother, more tangential).



The biggest problem was the plans had been drawn with some fundamental mistakes. Some of the arched patterns intersected the centre when sitting just below the outline and some intersected when sitting above. As you can see below, the two drawings do not even closely intersect (as they should).



I did my best and carried on till they were all down and splined.



The upper bout guide was a total mess so I decided to make the model a non cutaway. This meant I only had to use the left hand side of the last arch guide and mirror it over, to where the cutaway was.

Here is another shot of the non intersecting arches and the centre line.



Once the splines were all done, I was ready to do the surfacing.




I checked the templates and guides to see how well things were coming along. In general the spirit of the shape is there. It's not going to match perfectly because I’ve introduced symmetry for one thing.



If you look at the outline of the top (pic below), you can see that some of the arching templates are sitting either on the spline, or below it. That is because as mentioned earlier there seems to be a mistake in the drawings. On the incorrect arching templates (2,3,4), I cannot match the arching contour as it comes towards the outer edge. I did match the shape in the centre and for most of the arching, so I’m happy enough that it has captured what would have been there.


Here’s some pics of the model and recurve. The model looks like the recurve and the main surface are not very tangential but when you do a cross section analysis, you can see they are pretty nice and smooth. Could be better but certainly acceptable for a first go. No jagged edges etc..







Now onto the F-holes





Next cut the f-holes into the top, thickness the model, add some sides and a bottom plate (the top plate flipped over).



Here is a side shot showing the accuracy of the model to the original centre line in the drawing. Although I’ve bemoaned the lack of accuracy in the templates and that I’ve had to fly a little blind here and there, the overall shape has come out as close as you could likely get to the drawings and original design. I could improve the arched shape by another 25% to what I think would be a very good model of the original.









Again any misalignment between the drawing and the model it based on a lack of symmetry in the drawings and mistakes in the drawings. Well not mistakes but the nature of hand drawn plans.
The body drawing below is not accurate to the body drawing on the second sheet (above), as you can see from the model not matching it very well. I put the model over it for fun to see what it was like with the neck on.



I will thickness and graduate the plates according to the measurements another time. I will also make the neck. I’ll add this when it's done.

In the end these plans were kind of all over the place. I’m surprised they went up for sale but I think you can get something of use out of them. They missed some rather obvious dimensions. How tall are the sides etc.. Looking at the insane amount of recurve on the top plate (up to 60mm wide at places), it is likely that the original template for this was from a smaller 18” or 17” model.

I will do the Benedetto plans and the D’Angelico plans from Steve Anderson. Perhaps they will be more insightful. I think in truth however the best way to copy an archtop, is to scan it.

Kindest Regards

[Cunamara]

In terms of inconsistency in top and back carving, etc., I wonder if to a great extent that was the result of tap tuning and experience with the wood. Every piece of wood is different and those differences have to be accounted for in the precise final dimensioning of plate thickness, recurve, etc. I wonder if arch height would also vary between two tops based on what was noticed about the response of the wood during the carving process (e.g., was the top thinned from the inside resulting in a higher arch, or from the outside resulting in a lower arch according to the knowledge and experience of the luthier). An awful lot of that would've just been done by ear and feel. Neck angle would then be finalized relative to the height of the arch.

In that case the drawings, seeming flaws and all, might actually be a fairly accurate representation of that specific instrument as the design had been constantly adjusted throughout the build. Ribbecke is a pretty precise character, it seems.

As I think about it, the vibrational input from the strings through the bridge is going to be asymmetrical in several ways. The wavelengths coming from the low E string are longer than the wavelengths coming from the high E string; intonation requirements also usually put the bass side of the bridge closer to the tailpiece and the trouble side of the bridge closer to the headstock. An experienced luthier might asymmetrically carve the top responding to the different vibrational demands laterally across the top as well as mechanical loading.

Comparing that to the production process you have been developing, you could have more control because you could greatly determine the characteristics of the wood (laminate plates allowing choosing woods and adhesives) compared to carving out a solid slab of lumber with characteristics at the mercy of nature and that tree's growth, drying and aging, etc.

Of course, I'm a psychologist not a luthier and I might be just talking out of my you-know-what.

[Archie]

That all sounds plausible.

My guess is a combination of all the above.

1) Busy workshop
2) Did D’Angelico actually carve it?
3) Differences between drawing and measurement taking
4) The nature of old world techniques “handamde”.
5) Movement in wood and top over time
6) Health of person who made it.
7) Profit in making it
8) Size of guitar (the bigger the plate more easy to make mistakes).

I’m not sure about tuning. I think that is mostly done with the braces and recurve. The fundamental geometry should be sound. The thickness is mostly set by the stiffness and strength of the wood and the carving template. Small adjustments can be made after so yes, it could well play a part.
There might have been some defects or mineral pockets (pitch pockets), in the wood discovered when carving.
Fundamentally you do want the basic geometry of a dome to be there and central, if for anything, added strength through structural integrity and set up of bridge to neck etc..

[Rob MacKillop]

Well, in the lute and classical guitar world (Torres era) I don’t think you will find one instrument that is centred, and these are regarded as some of the best instruments ever made. Maybe they knew something? Or didn’t care? Modern luthiers either ‘correct’ the originals, or copy them exactly. The results either way are good or not so bad guitars, i.e. nothing conclusive. According to Torres, it was all in the feel of the woods, especially the soundboard.

In the current global market, few guitars are made by feel, and those that are demand a premium price. If your aim is to make ‘British Guitars’ that look the same (or thereabouts) and are every bit as good as machine-made guitars elsewhere, then I’m sure you will achieve that. But do you think you will be able to make them at the same price, or even cheaper for UK players? What do you think will draw players away from Asian machine-made guitars?

And what would be your USP? Throughout the last 100 years, British-made guitars have mostly had a related but separate identity to US or, say, German guitars. Likewise other European and non-European traditions. The British archtop history is a very interesting one, and I wonder if you would want to pay homage to that? Be an extension of that tradition? If not, I’m not sure you will have a USP strong enough to garner attention. Thoughts?

[cmajor9]

Its an interesting investigation, but (to echo other replies) why do you assume that what’s better/easier for the CAD program (more symmetry, smoother, more tangential) will produce a superior-sounding instrument? A more uniform and perhaps more cost-effective one to manufacture, probably yes. Rob’s questions about the selling proposition seem relevant here.

[Rodney Gene]

Well, in the lute and classical guitar world (Torres era) I don’t think you will find one instrument that is centred, and these are regarded as some of the best instruments ever made. Maybe they knew something? Or didn’t care? Modern luthiers either ‘correct’ the originals, or copy them exactly. The results either way are good or not so bad guitars, i.e. nothing conclusive. According to Torres, it was all in the feel of the woods, especially the soundboard.

I agree Rob.

When you play a truly, slow built hand carved archtop, they are alive, they breathe and sing. Imperfect and very musical - slow tuned, hand tuned, an intentional set of ears understanding the wood and hearing what that particular combination of woods was doing, could do, and then maximizing the strength and individuality of it. Progressively adjusting with patience. Adjusting more with every new added change to the build (glues, bracing, bridges etc).

Modern CNC machines are exceptional at consistency, but they can't listen. Not to mention modern builds are made for durability - A great archtop has a bit delicacy to it's tones and that is preserved in the process. We see alot of pretty good guitars from CNC machines with the occasional really great guitar, unintentional, as a product of the odds only. But exceptional guitars require some relationship with the builder. As far as modern builders, Eastman guitars, all costs aside, preserve more lightning in a bottle than most for modern mass produced Archtops in my experience. They have more individuality built into their homogenization than most.

[Rodney Gene]

In terms of inconsistency in top and back carving, etc., I wonder if to a great extent that was the result of tap tuning and experience with the wood. Every piece of wood is different and those differences have to be accounted for in the precise final dimensioning of plate thickness, recurve, etc. I wonder if arch height would also vary between two tops based on what was noticed about the response of the wood during the carving process (e.g., was the top thinned from the inside resulting in a higher arch, or from the outside resulting in a lower arch according to the knowledge and experience of the luthier). An awful lot of that would've just been done by ear and feel.

^^

This.

[AllanAllen]

I think this process is very interesting and if it ends up putting another full body, full scale archtop on the market that’s even better.

Eastman’s are great and all, but that 25” scale is a compromise for me.

[Archie]

Since everyone above is making the same sort of comment and has the same questions, I’ll respond to you all in this message.
I don't know how to do multiple quotes in one response.

CNC Guitars:

CNC guitars are not better or worse. The term really describes people who prefer their plans to be created to exact dimensions. The repeatability of this is another part of it, thus opening up more options than traditional carving. This is why when I talk to luthiers, I’m careful to emphasise that I’m not a luthier. I’m more like an engineer seeking to design and produce something that is made to the highest possible standard (dimensionally). Even though, it still has to be based on an idea; without the idea, there’s nothing.

I got into this because I was sick of Gibson’s poor quality. It’s not a secret that I don't think much of their systems and manufacturing. That lit a fire in me to say “this can be done better and at a fair price”. Lots of people love Gibson archtops but they have been machine carved since the 1940’s (to a relatively low standard imo), so why not do it to a higher standard?

There is potentially a misconception about CNC machines. A CNC doesn't do anything. A CNC machine sits around doing entirely nothing, until someone who has designed a model and created a tooling code, comes along as says “cut this like that”. A CNC is therefore an extension of someone. If I took these D’Angelico plans and made the prefect replica and luckily had a nice piece of wood, that sounded great and it turned out that my version sounded better than the original, it still would not be down to the CNC. It would be down to my CAD work, CAM strategy and skill in machining. All three aspects make up the end result.

People and luthiers seem to be somewhat deterred by the inclusion of "machines" and "production" but in reality, the machines I have do not make guitars. No machine makes a guitar. The person operating the machine, who designs and makes the tooling, to achieve a desired outcome, makes the guitar. My wide belt sander is very accurate but it doesn't make guitars. It doesn’t even sand veneers. It makes a component for a guitar in the way I have designed it to, for a specific outcome and level of accuracy. I use the machine because I know it can do something very accurately and I steal that accuracy to make it do something else. All of this thinking and forethought, goes into making each component.

A phrase I came up with is “The quality of a part depends on the systems that produced it” and from that "Perfection is lots of little things done well”.

When i’m talking about Geometry, then yes CAD absolutely does better geometry. That is entirely what it is designed to do. Does it make for a better sounding guitar? No. Does it make for a better playing guitar? No. The person using the CAD is the one that will determine that; but everything is built on a set of laws, especially guitars and in CAD those laws become physical instead of intuited. Hence why I comment about letting the CAD do what it does best, in order to make a “better" component.

I’ll try to demonstrate what I mean regarding letting the CAD do the work, to create better geometry (not a better sounding guitar) and by “work” this has to be guided by the user, CAD only does what you tell it but once under instruction, it can in turn guide you. You are then free to go with the flow or to over ride it. But absolutely the use of CAD and CNC machining, will almost always make for a better playing guitar, if the operator knows what they're doing.

[Rodney Gene]

Since everyone above is making the same sort of comment and has the same questions, I’ll respond to you all in this message.
I don't know how to do multiple quotes in one response.

CNC Guitars:

CNC guitars are not better or worse. The term really describes people who prefer their plans to be created to exact dimensions. The repeatability of this is another part of it, thus opening up more options than traditional carving. This is why when I talk to luthiers, I’m careful to emphasise that I’m not a luthier. I’m more like an engineer seeking to design and produce something that is made to the highest possible standard but based on an idea. Without the idea, there’s nothing.

I got into this because I was sick of Gibson’s poor quality. It’s not a secret that I don't think much of their systems and manufacturing. That lit a fire in me to say “this can be done better and at a fair price”. Lots of people love Gibson archtops but they have been machine carved since the 1940’s (to a relatively low standard I might add). So why not do it to a much higher standard?

There is potentially a misconception about CNC machines. A CNC doesn't do anything. A CNC machine sits around doing entirely nothing, until someone who has designed a model and created a tooling code, comes along as says “cut this like that”. A CNC is therefore an extension of someone. If I took these D’angelico plans and made the prefect replica and luckily had a nice piece of wood, that sounded great and it turned out that my version sounded better than the original, it still would not be down to the CNC.

People and luthiers seem to be somewhat deterred by the inclusion of "machines" and "production" but in reality, the machines I have do not make guitars. No machine makes a guitar. The person operating the machine, who designs and makes the tooling, to achieve a desired outcome, makes the guitar. My wide belt sander is very accurate but it doesn't make guitars. It doesn’t even sand veneers. It makes a component for a guitar in the way I have designed it to, for a specific outcome and level of accuracy. I use the machine because I know it can do something very accurately and I steal that accuracy to make it do something else. All of this thinking and forethought, goes into making each component.

A phrase I came up with is “The quality of a part depends on the systems that produced it” and from that "Perfection is lots of little things done well”.

When i’m talking about Geometry, then yes CAD absolutely does better geometry. That is entirely what it is designed to do. Does it make for a better sounding guitar? No. Does it make for a better playing guitar? No. The person using the CAD is the one that will determine that; but everything is built on a set of laws, especially guitars and in CAD those laws become physical instead of intuited. Hence why I comment about letting the CAD do what it does best, in order to make a “better" component.

I’ll try to demonstrate what I mean regarding letting the CAD do the work, to create better geometry (not a better sounding guitar) and by “work” this has to be guided by the user, CAD only does what you tell it but once under instruction, it can in turn guide you. You are then free to go with the flow or to over ride it.

Cheers Archie - speaking for myself only here I don't read any misconception about CNC machines here in these comments.

They are fantastic and revolutionary for most guitar work - the consistency is almost always the goal and after 4 decades of use in this industry, they are indispensable and have upleveled modern production. Particularly with solid and semi hollow instruments. I think builders who use a combination of CNC and hand carved work do the best work in this day and age. But, being this conversation is revolving around wood and individual wood tonality/characteristics, as it pertains to it's roles and/or functions in an archtops, your reoccurring point that 'CNC machines don't do anything' is really the same point that is being emphasized.

But you are absolutely right, there is a physics and science behind all of it, and precision in those areas can create advantages that are greatly supportive. I love experimentation in this industry and am fascinated by your intent here. I do think with archtops (or fine violins, cellos etc) however, the art of the build, the human touch, has unmatched relevance. There is just no way around that. I know you say you are not a luthier, but rather an engineer, I really respect that. I appreciate you are coming at this from a different perspective, that's cool. Hand carving a top is similar, I think, to the art of Michelangelo for instance, where marble is removed to reveal what is the artists vision was. A bit grandiose analogy, but also not.

[GuyBoden]

Excellent stuff.

Speaking from a non-guitar building, but an Engineers point of view, over the years the Art of craftmanship has been analysed and codified. To the extent that CNC and other machines can do most of the work. Final assembly is usually done by hand.

[deacon Mark]

The archtop makers I have been around certainly had plans and dimensions that were exact in terms of what the guitar was and the part. However, to me they were really chefs in the kitchen and once they got into the build things can happen. It was fluid and very artistic in the sense of what to do and where to go. Bill Hollenbeck was fascinated by using this tuning fork and feel to get the top thickness. He had exact readings on a template but once he began it was all how the top reacted as he carved.

Bill Barker was a bit more interested in the bracing and shaving the braces once they were in and top pretty much at the proper thickness. He would at times shave or shape a brace a bit to change response. This was all intuitive and nothing that CAD could do except take and reading and on the next top try to duplicate the dimensions. That sounds good but truth is the piece of wood is different so it will be different.

In the end it is like baking. I mix up some sourdough according to an exact formula. But each starter batch has a different level of fermentation and response. Things can be uneven or even but never really the same. Archtop guitars of solid wood and carved all react differently and require duplication only to a certain point. When you get to that point you then make the acoustic guitar that will only be " that" particular guitar. It is fascinating really. It is like playing the guitar and your individual sound. I can play the same notes and line as Kenny Burrell, but my touch is not like his so it will not sound exactly the same.

[Archie]

Cheers Archie - speaking for myself only here I don't read any misconception about CNC machines here in these comments.

They are fantastic and revolutionary for most guitar work - the consistency is almost always the goal and after 4 decades of use in this industry, they are indispensable and have upleveled modern production. Particularly with solid and semi hollow instruments. I think builders who use a combination of CNC and hand carved work do the best work in this day and age. But, being this conversation is revolving around wood and individual wood tonality/characteristics, as it pertains to it's roles and/or functions in an archtops, your reoccurring point that 'CNC machines don't do anything' is really the same point that is being emphasized.

But you are absolutely right, there is a physics and science behind all of it, and precision in those areas can create advantages that are greatly supportive. I love experimentation in this industry and am fascinated by your intent here. I do think with archtops (or fine violins, cellos etc) however, the art of the build, the human touch, has unmatched relevance. There is just no way around that. I know you say you are not a luthier, but rather an engineer, I really respect that. I appreciate you are coming at this from a different perspective, that's cool. Hand carving a top is similar, I think, to the art of Michelangelo for instance, where marble is removed to reveal what is the artists vision was. A bit grandiose analogy, but also not.

Well made point Rodney and I can tell you’ve given this all quite some thought.

At the risk of throwing myself in the deep end again (which I typically do), I think there is a lot of “romanticising” when it comes to the “slow cooking” method.
We’ve all played archtops by great luthiers that we kinda thought “hmm” and I’m sure Luthiers have finished many a guitar they wish had turned out slightly differently.
At some point, the product has to be finished and shipped. The more of a reputation you garner the harder it is to spend the time perhaps needed to put that extra 20% in.
I've never seen any of D’Angelicos work in plan before but if these plans are to be taken at face value, it’s the worst carving I've ever seen. I doubt there is any real “higher level cooking” going on, but rather someone who’s being harassed for an 18.5” archtop that they're being underpaid for, or it's for a friend but not that good a friend.
I’m sure it sounds great and could show the opposite, not that this man is at one with the individual wood; but given some basic design principles, most of what they do will turn out sounding pretty good regardless of the wood.
I’m not saying a definite either way but I’m not swayed so much by dogma or legend.

For all the talk of Stradivarius, no one can consistently put the sound of his violin above that of another good maker in a blind test. The market will always coalesce around one maker, period or thing. That’s what people do. It doesn’t bind me or convince me of anything.

Start with first principles and work from there. The person who can rapidly prototype and learn and repeat, measure and mark, will make the most progress, no matter how they do it.

[Archie]

The archtop makers I have been around certainly had plans and dimensions that were exact in terms of what the guitar was and the part. However, to me they were really chefs in the kitchen and once they got into the build things can happen. It was fluid and very artistic in the sense of what to do and where to go. Bill Hollenbeck was fascinated by using this tuning fork and feel to get the top thickness. He had exact readings on a template but once he began it was all how the top reacted as he carved.

Bill Barker was a bit more interested in the bracing and shaving the braces once they were in and top pretty much at the proper thickness. He would at times shave or shape a brace a bit to change response. This was all intuitive and nothing that CAD could do except take and reading and on the next top try to duplicate the dimensions. That sounds good but truth is the piece of wood is different so it will be different.

In the end it is like baking. I mix up some sourdough according to an exact formula. But each starter batch has a different level of fermentation and response. Things can be uneven or even but never really the same. Archtop guitars of solid wood and carved all react differently and require duplication only to a certain point. When you get to that point you then make the acoustic guitar that will only be " that" particular guitar. It is fascinating really. It is like playing the guitar and your individual sound. I can play the same notes and line as Kenny Burrell, but my touch is not like his so it will not sound exactly the same.

I agree with that and thanks for sharing. CAD gives you an advantage with necks, formers, jigs, rapid prototyping and design alterations with often micro changes being applied in an accurate and measurable way.

In the below video the CAD gives accurate mono and dipole readings from an arched plate model. Most of it goes over my head but the results in the end are quite incredible.

[skykomishone]

Steve Andersen published a '48 New Yorker plans in the Luthiers Guild publication too.
Archtop Guitar Plans
Guild of American Luthiers
Archtop Guitar Plans – Guild of American Luthiers

[Archie]

Steve Andersen published a '48 New Yorker plans in the Luthiers Guild publication too.
Archtop Guitar Plans
Guild of American Luthiers
Archtop Guitar Plans – Guild of American Luthiers

Thanks Sky. I will give them a go at some point. I’ll try and make the neck and gradient the plates on this beast first.

[Rodney Gene]

Well made point Rodney and I can tell you’ve given this all quite some thought.

At the risk of throwing myself in the deep end again (which I typically do), I think there is a lot of “romanticising” when it comes to the “slow cooking” method.
We’ve all played archtops by great luthiers that we kinda thought “hmm” and I’m sure Luthiers have finished many a guitar they wish had turned out slightly differently.
At some point, the product has to be finished and shipped. The more of a reputation you garner the harder it is to spend the time perhaps needed to put that extra 20% in.
I've never seen any of D’Angelicos work in plan before but if these plans are to be taken at face value, it’s the worst carving I've ever seen. I doubt there is any real “higher level cooking” going on, but rather someone who’s being harassed for an 18.5” archtop that they're being underpaid for, or it's for a friend but not that good a friend.
I’m sure it sounds great and could show the opposite, not that this man is at one with the individual wood; but given some basic design principles, most of what they do will turn out sounding pretty good regardless of the wood.
I’m not saying a definite either way but I’m not swayed so much by dogma or legend.

For all the talk of Stradivarius, no one can consistently put the sound of his violin above that of another good maker in a blind test. The market will always coalesce around one maker, period or thing. That’s what people do. It doesn’t bind me or convince me of anything.

Start with first principles and work from there. The person who can rapidly prototype and learn and repeat, measure and mark, will make the most progress, no matter how they do it.

Cheers! I appreciate that and of course, I understand.

I think it is relevant to read through any of this dialogue on a really small scale - meaning the conversation about percentages', 'details', 'tonewoods', etc..is already happening in the last inch of the mile. Concepts can be (and often are) discussed in extremes with tones, but If you blow out the conversation to the scale of the average consumer, it's nearly all a moot point. After enough years in the tone and gear game, you tend to develop preferences and you really do hear the differences (in extremes often) that are too subtle for many to notice or care about. I am referring to the entire chain, whatever that may be. I think there is enough geekery, experience and tuned intention here in the conversation to support relevant thought about it all. It's an impressive goal (and drawings) regardless. 'Talking shop' is always enjoyable with others who relate!

[Cunamara]

Related website: The Archtop Project

And also Euphonics – The science of musical instruments ISSN 2977-5612

[Archie]

Related website: The Archtop Project

And also Euphonics – The science of musical instruments ISSN 2977-5612

I tried contacting the Archtop project some time ago but their email doesn't seem to work.

Thanks for the links. I’ll look up Euphonics.

[Archie]

I spent a bit more time on the top plate today and I brought the dimensions and shape closer to the drawings.
The top has now been graduated to the original carving.




The problem I’m having, is the closer I get to the drawings, the weirder and frankly the more odd, the shape seems to get.

Here is the internal shape before the recurve. You would expect this to follow somewhat closely to the shape of the outline but here, the bottom half of the shape seems to get very weird.
I can't comment on whether this is good for acoustics. I can only comment on it from a geometric view point.

Here is a view from the back to show that the bulge in the bottom 3rd is in the plan. As you can see I've matched it almost perfectly.

Here is the over all shape.



This “strange” shaping does not stop there and really continues throughout the plans. It was very difficult for me to graduate the top because everything is so off. Part of this is definitely the plans but part of it is the guitar itself.

I’m going to do my interpretation of it next, basically how I would like to have seen it carved. Again this is not a comment on how it sounds. I’m going to clean up the geometry and make the graduation more uniform but based on the principles D’Angelico uses, thicker in the centre, thinner as it gets to the recurve. I’m also going to remove a few of the guides and positions to help create more flow. My aim is to create a more attractive plate and one that has better fundamentals. As if I’m creating a base for a luthier to then work on.

[deacon Mark]

Steve Andersen published a '48 New Yorker plans in the Luthiers Guild publication too.
Archtop Guitar Plans
Guild of American Luthiers
Archtop Guitar Plans – Guild of American Luthiers

This is interesting seeing the Anderson 1948 version. I wish I could read all the measurement because it fits my 1949 New Yorker I think pretty close. The key is the scale length. My 49 is this exact scale length and I went to great trouble to get measurement because it is a bit of and outlier. Normally we see 25.5 but Dangelico's are all over the map as John was working custom. My 1937 is 25.75 huge. Also, my 49 is 18.25 inches at the lower bout.

[Archie]

Here’s my redesign of the “original" plate. I say original but that has already been massively cleaned up. Originally tried to adhere to the plans the best I could and improve then drawings where needed but wanted the original shape to be present.
On the new version, I’ve ignored a lot of the original guides and instead created a new internal body based on the outline of the guitar and some core measurements regarding the thickness of the plate at the centre and outer edge.

The original is on the left, my version is on the right. Worth noting that the “original” is much more symmetric and cleaner than the actual plans.



Some shots of the new plate






Both the new and original side by side in a cross section analysis. The original is on the right. I managed to keep the graduations really close.







I think the new design allows a good platform for a luthier to work off of. You know the arch is central, the graduations are perfectly consistent, the plate is perfectly symmetric. This allows one to take off just what they need knowing that the core geometry is essentially prefect.

[mrwoland]

Wonderful!

[Archie]

I’ll try and fit the internals later today.

I’m tempted to use Gibson styled parallel bracing. The post 50’s type with the satellite braces at the waist and lower bout.
I’m sure a 18.5” archtop will be mellow enough without the need for X bracing?
An over braced Gibson style pattern will allow for a more even tone and increased assurance against the plate cracking.

Does anyone have any objections/thoughts?

[Archie]

Finished the internals. The Body is now ready to be machined, although that won’t happen for some time as I have other projects I need to get on with.

The blocks, kerf and braces are to size. I changed the neck block from a cutaway one to a non cutaway one by taking half of the drawing and mirroring it. I did a dovetail neck pocket too.
Interestingly the neck block and flat outer on the underside of the plate aren't the same depth so the to plate lifts up before the end of the block. Looks kinda strange and not something I've seen before. All that remains is to do the CAM.

I looked on the drawings and couldn't find a measurement for the height of the braces so I just put in a temporary number.