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Thread: Aluminum Archtop Build

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    Aluminum Archtop Build

    This is a set of updated images and a diverted discussion from a thread about feedback. The last message I posted in that thread is pasted below, you can link back to the feedback thread from there. The internal parts are not yet in their final form in these images.

    I'll post a full description of this project a little later but briefly the body will be all aluminum with a bolt-on wood neck. It is based on an ES-335.

    One thing mentioned in the other thread was my need to come up with a weight budget for the body. If anyone has some numbers for a dual-humbucker guitar with a bolt-on neck, that would be very helpful. Specifically I'd like an all-up weight and a weight for the body only -- finished but stripped of all removable parts.

    I wasn't even sure I was going to do this build but it now appears that it's at least possible based on my CAD model. Whether or not my skills are up to the task is a separate question. This will require machined parts, 'shaped' sheet metal parts, welding and some tricky assembly work. The body will be polished so if I don't do a proper job on the panels, it will look like s--t.



    Quote Originally Posted by yankeerob View Post
    I think you will wind up with something - despite it's being hollow - that will have a very 'linear' response - if you recall the likes of Travis Bean and early Kramers - they had great sustain but there was 'something not quite right' with regard to the interaction of string and body resonance
    Those two guitars were aluminum necks on wood bodies, correct? My project is more like a Normandy or Alumisonic were the body is metal and the neck is wood. Are those guitars selling? I don't know, you don't commonly see them but there are a lot of guitars from small shops you don't commonly see.

    As to the linear characteristics, that may well be the case with my design, I'm not experienced enough to have any intuition here. What you're saying (I think) is that wood acts as an EQ device that colors the tone in a familar way that makes a more linear instrument sound 'funny'. I wonder how much of that is the neck and how much is the body. Again, no intuition here but logic says the neck is a bigger part of the system that supports the strings so it might have the larger effect. I'd love to hear comments from anyone that has heard a Normandy or Alumisonic in a live setting, or better yet, played one.

    Does a pedal steel have a linear tone response? Those are very rigid with tons of sustain and some designs feature non-wood construction. Or does a pedal (or lap) steel guitar's tone sound OK because it's a different instrument with it's own character?

    Quote Originally Posted by yankeerob View Post
    .......plus the neck took a long time to warm up on a cold day and it just never felt quite right...
    Another aspect I had not considered -- differential thermal expansion. The structure in my design's body may take a while to stabilize because it's inside a shell and somewhat isolated from the shell by the adhesive I intend to use in lieu of visible fasteners. The bond joints will be thin and have a lot of area so there might be decent heat transfer. Until it all finds a happy temperature the tuning may want to wander a bit. That's probably the case with any instrument, it will be a little worse with aluminum.

    As far as feel goes, the player interacts primarily with the neck so I'd expect my guitar to feel somewhat familiar.

    Quote Originally Posted by yankeerob View Post
    regards a weight budget for the body you're just going to have to accept there's a minimum thickness of top and back that will be practical and you'll most definitely be governed by that...
    Yes, I think .050" (1.25mm) is getting pretty thin. I can weld thinner metal successfully but the result would be more prone to dents where the metal is soft (near the welds). What I can do is lose weight in the braces to allow thicker panels. With CAD, I can apply loads to the brace parts and see what I can remove without losing much rigidity. At some point you'll be hurting the structure by removing too much material. I have not optimized the structure yet but it looks like my 3.5 lb initial target is going to be too low. I'm a little over 4 lbs now and I'll be fighting to get that below 4 lbs, I just don't see it getting much below that number. There's not much structural contribution from the body's shells so I don't get anything back by shifting the material to the panels.

    Thanks Rob.........Bill

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    Re: Aluminum Archtop Build

    Missed the other thread. IMO Joey Bonamassa's best sound is thru that alum body Gigliotti Tele he plays.

    http://www.youtube.com/watch?v=ZDrD6HTqsoI

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    Re: Aluminum Archtop Build

    cw's project above is listed as all aluminum. Bonamassa's Gigliotti (like all Gigliotti guitars) has an aluminum (or brass as an option) top set onto a wooden body. And I agree, it sounds great.

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    Re: Aluminum Archtop Build

    This project started a long time ago, I just didn't know it. Several things came together – my desire to build a guitar, my interest in metal shaping and my career in engineering. My guitar building thoughts got serious when hurricane Charley took out some or our largest maples. I figured it would be cool to use wood from one of those fallen trees as the body of a T-style build. In 1991 a concept car was built by Audi called the “Avus” and it featured a polished aluminum body – and it made a big impact on me. Since I was working as a hands-on engineering tech I had been doing fabrication for years. I have also been involved in aviation since I was 14. Airplanes use shaped metal parts and many of these were hand made in years past. I had already built and rebuilt several airplanes. I wanted to learn the art of “panel beating” (as the Brits called it) and started collecting tools, reading, and doing small projects. It was in the last few months, with time on my hands because I had been laid off, that this vision of a polished aluminum ES-335 started haunting my brain.

    And it wouldn't go away. As the details started to clarify in my mind, I felt the need to do some formal design work. I bought a set of plans for an ES-335 and the seller was kind enough to provide some of the plan's content as CAD files which saved me a lot of time. I figured going through the design process would be a good way to rid myself of those visions, finding some reasons why this won't work without major compromise. Instead I found out it could be done so I kept working on it. The results of that work are seen in the images I have posted so far. There's more design work to be done and it's been a great outlet for my creative side as well as a way to keep my head in the game professionally. I am fortunate to be able to use the facility where I used to work. It's a fairly complete machine shop and the seat of Solidworks (3D CAD software) I've been using for the last ten years is available to me. It also has all my metal-working tools – my hammers, dollies, shot bags, pneumatic planishing hammer and the 'English wheel' I built from plans about 20 years ago. And there's a TIG welding machine too. To say I still have a close relationship with my former employer is an understatement. I've been associated with them in one way or another since 1976 and our association may continue if things turn around for the company. Or they may need to sell the facility where I'll be building this guitar. Hopefully the building will remain available and I can continue to use it for my own purposes.

    more---------->
    Last edited by cwilliamrose; 04-14-2010 at 09:12 AM.

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    Re: Aluminum Archtop Build

    There are several guitar designs similar to the one I'm working on. The two I know of that are closest to mine are made by Normandy and Alumisonic. But there are things about mine that are unique. I want to build a body without visible fasteners – no big rivets like the Normandy. I want a polished body finish unlike the Alumisonic which is chrome plated. I don't want any wood in the body. I want to build the body by hand. I don't want to build a neck (right now anyway). I want it to look like an ES-335. I wouldn't mind that it sounded a bit like a one too but I'm realistic enough to know it won't. It will sound like it sounds because it's not quite like any other guitar. I'll be disappointed if it feeds back uncontrollably. As a designer I'll be upset if I can't keep the weight in the right ballpark or if the balance is way off. And I really, really really don't want access holes in the body. If it turns out to be a lousy instrument it damn well better look good hanging on the wall!

    more------------->

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    Re: Aluminum Archtop Build

    I have made many of the basic choices regarding the build's details. It will be a welded body and the corners will be rounded to help control distortion often seen when welding a sharp corner. The welds will run along the center of the corner radius. I will use a machined or a combination of machined and fabricated braces inside the body to carry the string loads, mount the pickups, tailpiece and bridge. There will be structural bracing all the way to the strap button at the bottom of the body. The braces will be in at least four pieces (so I can get them inside the body through the large neck/neck PU hole) and will be joined after being inserted in the completely welded body. They will be bonded to the body at selected places chosen mainly for my ability to actually assemble the parts.

    more------------------->

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    Re: Aluminum Archtop Build

    The body shell will be largely non-structural but it will see loads from the player's handling of the instrument and it does need to be well attached to the structure so the strings have a good connection and can resonate properly.

    Other things remain undecided. One is the mounting of the bridge and tailpiece. A wood guitar has a bushing pressed into the wood. That won't work for me on this design. At first I thought to eliminate the bushings, tap the braces and screw the adjusters directly into the guitar. Cool! Simple, easy, perfect. Not. I need to connect the neck braces to the ones running to the bottom of the body so I'll use large holes, just like a wood guitar, and use those holes as a large counterbores for the 1/4-20 cap screws that will tie the neck braces to the bottom braces. Do I tap the big holes and make large adjusters to fit those holes? Or do I make custom bushings and use standard Gotoh adjusters? Less parts are generally better so I'm leaning toward a 'no bushings' approach.

    I was unsure how much detail to go into during this build but as you can see I'm not going to hold back. I'll have a better result if everyone here can see where it's going and make suggestions. If someone out there steals my work and calls it their own, we'll know the truth.

    I'll try to post an update mid-week, after I have the braces farther along. I'll be ordering material soon but I'll need to make some fixtures and forming blocks too. I'll document the whole process in detail and post it here. Please feel free to comment. I may not use a given suggestion or agree with all the comments I get but I will benefit from them. This will be a huge learning experience for me and a equally huge challenge to pull off.......Bill
    Last edited by cwilliamrose; 05-18-2009 at 05:57 AM.

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    Re: Aluminum Archtop Build

    Quote Originally Posted by Gris View Post
    Missed the other thread. IMO Joey Bonamassa's best sound is thru that alum body Gigliotti Tele he plays.

    http://www.youtube.com/watch?v=ZDrD6HTqsoI
    That guitar sounds great but as pc said, it's largely wood. The body has a lot of routing that allows the top to be an acoustic element. Two things I learned from the Gigliotti site -- the feedback is well controlled (according to JB) and they use silicone adhesive. The second one is most enlightening as I am looking at two adhesives for mine, one is going to be somewhat flexible like silicone would be. I feared it would be too much of a vibration dampener but maybe not.

    Thanks for that link, it's encouraging..........Bill

    P.S. I love the finish on those guitars but I'll still polish mine.

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    Aluminum Archtop Build, Design Update

    I have a better idea of what the parts inside the guitar will look like and what they will weigh. I also did some analysis of the structure, looking at both deflections and weak spots.


    This image shows the load I simulated. There are two posts with flat spots which put the string tension loads in the right place (those posts are not part of the design). The load there is 75 lbs per side. I found a string tension calculator on a website and with an .011-.054 set it's showing 141 lbs. I'm also putting some load in an upward direction since the string tension is not exactly in the direction of the arrows and the player could add to that by the instrument is handled. It's a little bit of a guess but it's a place to start. The heel is restrained in this simulation (the neck is fixed in space).


    This is the result. The loads are highest at the yellow and red colors. Those areas are very small and I generally ignore small indicators because I know they're not showing a real-world condition. And most of those little spots are in compression anyway. The red arrow shows the material's yield point, in this case 6061T6 aluminum. In general the stresses on the brace are pretty small. I can also display the results as deflection instead of stress and this is the method I used to take out some weight without adding undue deflection to the part.

    The reason I'm loading the braces as a unit is that loading a single side showed the brace wanting to twist in reaction to the applied loads and the plate that ties them together stops that twisting. It's not something I had planned on adding, the simulation pointed out the need. All this ignores any contribution from the body's shell.


    Here's where I'm at weight-wise. It includes the fasteners used to hold the brace parts together but not the adhesive and weld. The body, ready for assembly into a guitar weighs 3.7 lbs. This is with a .050" panel thickness. I add something like .5 lbs if I go with .0625" sheet stock instead of .050". Depending on the weight of the rest of the parts, I may be able to use the thicker material. The pink triad is the center of mass.



    And finally, some images of the brace assembly on it's own and inside the body.

    I want to do a build sequence of images to show how I get all that stuff inside the body after it's welded. I'll save that for another post........Bill
    Last edited by cwilliamrose; 05-28-2009 at 03:23 PM.

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    Aluminum Archtop Build, Form Block Started

    I have started to process of creating the form block for the body panels. It is basically a chunk of MDF that would fill the interior of the body. It won't have the arch-top's shape but will have the other features. I want the body's corners to be rounded either 5/16" or 3/8" outside. I'll start with 1/4" inside and change it to the larger radius if it doesn't look right to me. The idea of the radius is to contain the weld and help prevent distortion in the welded parts by having a stiff shape around the weld. If I were just welding the corners together in a simple, square design, I wouldn't really need the form blocks.

    I'm using 1/2" MDF because it's a nice consistent material that's fairly soft. Since I will be shrinking the panels where the corner radius is on a convex shape, I don't want a hard surface under the part. Hard surfaces tend to compress the metal when you strike it which causes it to stretch instead of shrink. I'll probably have the anneal the edges of the panels to allow me the shrink it down to the form block.


    I made a full-size pattern in two pieces by printing a CAD sketch from my model to our old Canon BJ-230 on 11"x17" paper. I glued the pattern to a piece of MDF.


    I cut it out on the bandsaw, leaving a bit of extra material outside of the lines.


    After a little light sanding, I had a template for the other four laminations.


    Tracing around the already generous template leaves plenty of material for final sanding to shape. The three holes will help hold the parts in alignment during assembly.


    I'll make two halves. The four pieces are about 3/8" thicker than I need so I'll take 3/16" off each half and then glue them together.


    One half, ready to clamp. The bolts will keep the two parts lined up while I clamp them.


    The clamps are shot bags. There's 200 lbs on this one.


    A good amount of glue running out. Should be strong enough to take a bit of hammering.


    Both halves, clamped with 300 lbs each. Tomorrow I'll take the thickness down and glue the two halves together. I wish I had a big thickness planer but I don't so I'll set them up on the milling machine and fly-cut them. That should make a big mess!

    ..........Bill

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    Re: Aluminum Archtop Build, Design Update

    Quote Originally Posted by cwilliamrose View Post
    I have a better idea of what the parts inside the guitar will look like and what they will weigh. I also did some analysis of the structure, looking at both deflections and weak spots.


    This image shows the load I simulated. There are two posts with flat spots which put the string tension loads in the right place (those posts are not part of the design). The load there is 75 lbs per side. I found a string tension calculator on a website and with an .011-.054 set it's showing 141 lbs. I'm also putting some load in an upward direction since the string tension is not exactly in the direction of the arrows and the player could add to that by the instrument is handled. It's a little bit of a guess but it's a place to start. The heel is restrained in this simulation (the neck is fixed in space).


    This is the result. The loads are highest at the yellow and red colors. Those areas are very small and I generally ignore small indicators because I know they're not showing a real-world condition. And most of those little spots are in compression anyway. The red arrow shows the material's yield point, in this case 6061T6 aluminum. In general the stresses on the brace are pretty small. I can also display the results as deflection instead of stress and this is the method I used to take out some weight without adding undue deflection to the part.

    The reason I'm loading the braces as a unit is that loading a single side showed the brace wanting to twist in reaction to the applied loads and the plate that ties them together stops that twisting. It's not something I had planned on adding, the simulation pointed out the need. All this ignores any contribution from the body's shell.
    fascinating.

    have you considered this project from a vibrational approach instead of structural?

    if you have the ability to take a guitar that you know sounds absolutely terrific, and you were able to induce guitar string frequencies at the bridge area, and then measure the resulting frequencies at the neck pocket, you would have a crude formula for what might make the body sound great.

    you would then, (if you can), simulate introducing those guitar string frequencies into the bridge area of your brace and see what frequencies actually made it through to the neck pocket. in theory anyway, the closer you could match the frequecies of the great sounding guitar, the better chance you might have of getting a killer tone from this project.

    right now you seem to have a formula for a light weight, ultra strong brace with no sonic properties.

    this is an awesome project. thank you for sharing it in such complete detail!

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    Re: Aluminum Archtop Build

    Using 6061T6 you'll be fine with the stresses, I'd be inclined to look a little at strain to make sure I don't end up with parts moving next to each other, but again, I think you'll be fine. I would radius the edges of the pickup cavities to eliminate stress concentrators may too. Since the sides of the work you show are basically I beams they carry the stresses in the upper and lower parts and not the web, so lightening holes in the web would be a consideration.

    I'd be inclined to move the forces in the Z direction to the posts instead of the bottom of the part too.

    I would also look at the individual string tensions and vary the loads on either side to account for the delta in string tensions between the bass and treble strings. You can probably just do a linear approximation - as long as the sum of the forces is the same in all cases it would be pretty good.
    "No harmonic knowledge, no sense of time, a ghastly tone, unskilled vibrato, and so on. Chuck is one of the worst guitar players I know" -Gravity Jim

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    Re: Aluminum Archtop Build, Design Update

    Quote Originally Posted by Custom 5 View Post
    have you considered this project from a vibrational approach instead of structural?
    I have thought about it that way but didn't know how to go about getting useful data. The software I have use of is somewhat limited out of the box. It has a lite version of the FEA add-on called COSMOS. That's what I used for the stress analysis. The lite version doesn't do assemblies, only individual parts. I had to mirror my brace features and add structure to tie them together in a similar manner to the real parts. What I ran through COSMOS was really four parts that get bolted together. Even with those limitations it was a useful exercise.

    The process you described would be fun but I don't have any tools to help me do that.

    Quote Originally Posted by Custom 5 View Post
    right now you seem to have a formula for a light weight, ultra strong brace with no sonic properties.
    The brace has sonic properties, I just don't know what they are. It's really a system where the brace assembly, the body shells and the adhesive (and the joint itself in terms of thickness) all play a role along with the neck and it's joint design. Modeling that system accurately enough to be helpful wouldn't be easy but could probably be done with a sufficient budget. My four year old computer is maxed-out just doing the stress stuff. This is one of those things that could be discussed and out-guessed for months but you won't know where you're at until it's done and tested.

    This is why I started with the structure and the build sequence. I can control those and be reasonably sure it will be suitable as an instrument. I can guess it will sound a little like a resonator guitar, maybe a little like an ES and probably not have much in common with a solid-body but it's all going to be guess work.

    ................Bill

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    Re: Aluminum Archtop Build

    looking forward to hearing the results!

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    Re: Aluminum Archtop Build

    Quote Originally Posted by Offshore Angler View Post
    I'd be inclined to look a little at strain to make sure I don't end up with parts moving next to each other, but again, I think you'll be fine.
    I hope so, SWx/COSMOS doesn't do deformations other than a grossly exaggerated display of the model with the loads applied. I'm trying to give room between parts where they're not held together with fasteners. I don't want things buzzing inside the body.

    Quote Originally Posted by Offshore Angler View Post
    I would radius the edges of the pickup cavities to eliminate stress concentrators...
    Agreed. I don't like sharp corners for that reason and for the times when you need to get fingers inside and would rather not add blood to the finish.

    Quote Originally Posted by Offshore Angler View Post
    Since the sides of the work you show are basically I beams they carry the stresses in the upper and lower parts and not the web, so lightening holes in the web would be a consideration.
    I played around with that today.


    First I took the shear web out almost completely, just to get an idea about the possible weight savings. It turns out to be 0.1 lbs for the two parts. Of course the deflection increased by a factor of 3.5. It's only .0825" thick so there's not much there to begin with.


    Then I did some holes. The deflection increase was only about 4% but not much weight came off.


    So I looked at making bigger holes and still having some shear web left. This one added 10% to the deflection but saved more weight. But it's not so easy to machine compared to holes. I'll probably do some holes since there little reason not to. I'll play with the geometry some more to get the best compromise.

    Quote Originally Posted by Offshore Angler View Post
    I'd be inclined to move the forces in the Z direction to the posts instead of the bottom of the part too.
    I'm not sure that would make any difference (if I understand correctly). I didn't get a chance to try it yet. There's also a small load in the opposite direction under the bridge because of the string angle. I've ignored that so far.

    Quote Originally Posted by Offshore Angler View Post
    I would also look at the individual string tensions and vary the loads on either side to account for the delta in string tensions between the bass and treble strings. You can probably just do a linear approximation - as long as the sum of the forces is the same in all cases it would be pretty good.
    This is what I'm using for the tension numbers;

    Scale len 24.75"

    E .011" PL == 18.48#
    B, .015" PL == 19.29#
    G, .022" PB == 24.08#
    D, .030" PB == 25.53#
    A,, .042" PB == 28.2#
    E,, .054" PB == 25.49#
    total == 141.07#

    I could split them in two or even put them in as individual loads. Or I could exaggerate the bias to see what happens. I'll try it next chance I get.

    Thanks OSA, you're keeping me honest........Bill

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    Re: Aluminum Archtop Build

    I'd just split them so that the treble side post was the sum of the first three and the bass side the sum of the second three. If you keep them the same you could simplify things by only using half the part and constraining the centerline nodes in one dimension for the analysis. That would allow you to use a tighter mesh and get more detail. There's a tad of assymetry there in the loading for the strings however. It's probably not going to mean anything in reality, but I'm curious how it will affect the deflections. Since you know the bridge string spacing, you could use the sum of the moments to determine the actual forces on the posts.

    OK, being the total geek that I am I looked up the dimensions on a Gotoh tailpeice [3.25 post spacing and 2.0625 string spacing] and using your string tensions I calculated 74.56# on the bass side and 66.52# on the treble side. (Those numbers are rounded to two sig-figs - not only am I a geek, I'm apparently a rather anal one too!)



    BTW, what values were you getting for the deflections?

    The other consideration I'd look into is balance of the guitar. Nothing is more exasperating than a neck-heavy guitar. I had a wonderful sounding LP Double Cut that I flipped for that reason. If you only save 1.6 oz it's probably better to just leave the web there to lower the manufacturing cost.

    Nice looking part. How many axis machine are you cutting it with?
    Last edited by Offshore Angler; 05-30-2009 at 06:46 AM.
    "No harmonic knowledge, no sense of time, a ghastly tone, unskilled vibrato, and so on. Chuck is one of the worst guitar players I know" -Gravity Jim

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    Re: Aluminum Archtop Build

    Good thing it's a bolt-on. It's screaming for a carbon fiber neck later down the road. :)
    "No harmonic knowledge, no sense of time, a ghastly tone, unskilled vibrato, and so on. Chuck is one of the worst guitar players I know" -Gravity Jim

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    Re: Aluminum Archtop Build

    Quote Originally Posted by Offshore Angler View Post
    ...If you keep them the same you could simplify things by only using half the part and constraining the centerline nodes in one dimension for the analysis.
    The lite version doesn't let you do that, ya gotta' pony up for the full package. I had access to the full version which was installed on the company network but I don't any more. A lot of nerve they had cutting off my network privileges!

    Quote Originally Posted by Offshore Angler View Post
    ...That would allow you to use a tighter mesh and get more detail.
    I did try one at the finest detail it would allow last week -- it gave me effectively the same result but took 16x longer.


    Quote Originally Posted by Offshore Angler View Post
    ...There's a tad of asymmetry there in the loading for the strings however. It's probably not going to mean anything in reality, but I'm curious how it will affect the deflections...using your string tensions I calculated 74.56# on the bass side and 66.52# on the treble side....BTW, what values were you getting for the deflections?....

    This is the model without lightening holes, symmetrically loaded. 0.0255" max deflection.


    This is asymmetrically loaded per your ratio (I was using 150#, trying very hard not to be anal). Deflection=0.0262 max and if you look closely, you can see a bit of twist. Remember this displayed deformation is exaggerated by an order of magnitude or more. Maybe a .0015" delta bass-to-treble -- almost nothing.

    That deflection is about twice my intuitive guess. Seems too high. I should measure my CV Tele for calibration.

    Quote Originally Posted by Offshore Angler View Post
    The other consideration I'd look into is balance of the guitar. Nothing is more exasperating than a neck-heavy guitar. .... If you only save 1.6 oz it's probably better to just leave the web there to lower the manufacturing cost.
    This goes back to me needing enough info to create a weight budget or target for the assembled body. I have a neck coming (an eBay special, from a Epi LP Junior) but I don't have a pickup or tuners laying around I can weigh. I'll model the neck quick&dirty and get the CG and weight correct but it's probably maple and I'm thinking Mahogany for the 'real' neck.

    I have the option of adding ballast after it's finished by attaching some weight where the strap button screws into the body. Of course if you create a 10# guitar with proper balance it still kinda' sucks.

    Quote Originally Posted by Offshore Angler View Post
    Nice looking part. How many axis machine are you cutting it with?
    Thanks. It sort of designs itself once you have all the required stuff in place -- you just connect it all together and start trimming the fat.

    I have two machines I can use;

    1) A Series I Bridgeport with an x-y DRO and a separate digital readout for the quill. No Z-axis readout. Stock height -- no riser block.

    2) A Millport (BP knock-off) with a 4" riser but no DRO or even Traveldials. Nada. 0.02 lash in X and 0.01 in Y. Gotta remember that!

    I almost always use the Millport because the riser block makes it much more comfortable for my 6'5" frame. But it's Fred Flintstone all the way. I wish I had a 5-axis NC machine but I don't, hell even a two-axis retro for one of the mills would be great.

    This part will require multiple setups and some weird fixturing. Some things will be approximated and the surface that mates to the inside of the shell will have to be hand fitted. If I had to make more than one, I could get the parts quoted by an NC shop, tool the body panels, etc. I'm not thinking this will be a product, more of a one-off. If I get serious offers to build them for customers, I'll have to look at the costs for a small production run. That would be a nice problem to solve....Bill

  19. #19
    Forum Member rudutch's Avatar
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    Re: Aluminum Archtop Build

    you 2 don't happen to be engineers?
    do I look like I know what I'm doing?

  20. #20
    Forum Member Offshore Angler's Avatar
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    Re: Aluminum Archtop Build

    I am, but after 8 years of school they still won't let me drive the trains.
    "No harmonic knowledge, no sense of time, a ghastly tone, unskilled vibrato, and so on. Chuck is one of the worst guitar players I know" -Gravity Jim

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    Re: Aluminum Archtop Build

    Quote Originally Posted by Offshore Angler View Post
    Good thing it's a bolt-on. It's screaming for a carbon fiber neck later down the road. :)
    If Gris is correct that much of a guitar's tone comes from the neck, what would you say about a CF, AL and mahogany neck on a common body? I suppose a CF neck could have any number of design options (like golf club shafts) but maybe there's something general that can be said about these three materials.

    If it turns out a CF neck is just the ticket for this thing, I'll be taking up a collection.........Bill

  22. #22
    Forum Member Offshore Angler's Avatar
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    Re: Aluminum Archtop Build

    I think the guitar will sound pretty conventional. A resonator gets it's unique tone from the Al resonator cone. There are wooden resonators that sound like aluminum resonators, so extending that logic...

    The composite neck would be pretty cool. Aluminum necks where used in the past as well.

    The CF neck wouldn't be expenisve to make, but autoclaving it would be more work. I've built autoclaves out of styrofoam coolers before for small parts, so that can be overcome.
    "No harmonic knowledge, no sense of time, a ghastly tone, unskilled vibrato, and so on. Chuck is one of the worst guitar players I know" -Gravity Jim

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    Re: Aluminum Archtop Build

    After your mention of a CF neck, I found this;

    http://www.mosesgraphite.com/cgi-bin...c_Guitar_Necks

    Not a bad price and they do offer various scale lengths. One pass of the hat should do it........Bill

  24. #24
    Forum Member Offshore Angler's Avatar
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    Re: Aluminum Archtop Build

    I can probably kick in five bucks.
    "No harmonic knowledge, no sense of time, a ghastly tone, unskilled vibrato, and so on. Chuck is one of the worst guitar players I know" -Gravity Jim

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    Re: Aluminum Archtop Build

    Thanks, I'll hit you up for it when we have something to bolt it to.

    It's actually about the price of the Warmouth neck I was specing.....Bill

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    Re: Aluminum Archtop Build

    On the balance subject, I measured the two guitars I have. The CV Tele's CG is 81.4% of the scale length as measured from the nut. The Mustang is 82.8%. If there's a better way to express this, let me know. If anyone has a guitar you consider neck heavy, maybe you could do a quick measurement for me. Thanks.......Bill

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    Forum Member Custom 5's Avatar
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    Re: Aluminum Archtop Build

    Quote Originally Posted by cwilliamrose View Post
    If anyone has a guitar you consider neck heavy, maybe you could do a quick measurement for me. Thanks.......Bill
    anyone with a Gibson SG that would fit the bill!

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    Forum Member boobtube21's Avatar
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    Re: Aluminum Archtop Build

    Does a pedal steel have a linear tone response? Those are very rigid with tons of sustain and some designs feature non-wood construction. Or does a pedal (or lap) steel guitar's tone sound OK because it's a different instrument with it's own character?
    I realize you've made some progress since this thought..VERY impressive BTW...

    Keep in mind though a pedal steel player generally wears metal fingerpicks. This sounds radically different from just using your fingers. Some don't wear them but the pedal steel sound you hear on the majority of Nashville stuff I'm pretty sure is with metal fingerpicks. Another difference is a SUPER hot single coil pickup, raised up to about 1/8" below the strings, and action set at about, oh, 2" above the neck.

    The body of my pedal steel is maple I believe. Most are built this way, with an aluminum neck. Exactly how much of the neck is aluminum I don't know, but if we're talking a solid chunk to which the bridge and pickups are mounted that would definitely add to the sustain. Mine is a student model so I'm probably lucky to have an aluminum veneer glued on for an "authentic look".

    A lot of the sustain on pedal steel guitar also comes from careful use of the volume pedal.

    I think if you could strum a chord on a pedal steel in the style of regualr guitar it would sound pretty odd. Probably not good. However I think a purpose-built six string guitar constructed with aluminum will sound badass, can't wait to hear soundclips if/when you can get them up.

    Good luck.

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    Re: Aluminum Archtop Build

    I was thinking about the tone of the instrument but I guess you can't separate the inherent tone from the other influences like the picks.

    Good point about the volume pedal -- it's really "false sustain"...........Bill

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    Re: Form block about done, 'test' neck arrives

    The form block is just about ready to use. I've been thinking about doing one of the horns as a test of tool and method. It's one of the hardest areas because so much shape is happening in a fairly small space. I have some .063 aluminum sheet scraps that are probably large enough to make the parts for one horn. Plus, if it goes well, I'll have a nice inspirational chunk to look at and show friends and spouse.

    Anyway, here's some photos of the progress;


    This is the high-tech clamping system I'm using. I bolted a couple of short 2x6's to the mill table and took a cut on the tops to true them. The C-clamps get moved around as needed, as does the part, until the whole surface is down to size. This is the first half of the form block.


    It doesn't take long for the sawdust to get pretty deep. The shop vac was close at hand. The MDF material is very abrasive, it wears the cutter quickly. I'm kinda' glad I don't have a big thickness planer or I'd be spending money sharpening the blades three times just to get this done.


    Both halves thinned, glued and clamped.


    I've sanded the outer edge to it's final shape and the second to the last step is done; rounding the corners. I went with a 5/16" router bit which will give me a 3/8" radius on the finished part (the metal's thickness adds to the radius). The last step will be drilling a hole where the strap button goes. I'll use the hole as a place for a tooling pin so the rim stay put while I'm working on fitting it to the block. I need a hole in the rim for the screw anyway so I might as well use it for assembly.


    And the eBay neck arrived in good shape. It's not perfect -- someone seems to have played with the fret board finish. It's just what I need for pushing this project along, worts and all.

    The neck's heel is tapered like the fret board.It measures 2.28" at the 21st fret and about 2.22" at the 17th fret. I will need to trim some wood where the metal parts interface with the neck. If I do it carefully, it will look OK. The Warmouth neck should be a constant 2.19" width like a Fender and that's what I'll do with the neck pocket. I'll just have to make this temporary neck fit the body.........Bill

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    Worts & All + Balance + More Parts for the Build

    In keeping with the worts & all experience, here's a photo of the test horn parts I worked on today;



    The one on the left is the first one, where I rolled the edge, then worked on raising the center of the panel. It was a struggle doing it that way, mainly because it didn't want to stay flat around the edge. I wanted to do one each way so the second one was done raising the center first and doing the rolled edge last. I didn't get that far.

    The second one was actually looking OK but I wasn't getting enough shape so I decided to exaggerate the raised center just to see if I could get more than I need. The answer is yes. It's not smooth but it is flat around the edges and I have probably 3-4x the amount of shape I need in that area. I did a quick polish job just to see if it looked as bad as I thought it would. It confirmed for me that it sucks. It looks even worse in the photo!

    One problem I had both times was the work hardening of the material. It responded well to a torch anneal. That process is simple -- using an oxy-acetylene torch with a rich flame, you coat the surface of the aluminum with a thin layer of carbon. Then using a neutral flame you heat the metal slowly until the carbon burns off which happens at 800°F, the ideal temperature to anneal 6061. The metal got soft but got hard again with very little working. Feels like 5052 instead of 6061 to me and it could be, I'm using unmarked scraps for my tests parts. I have some .040" 6061T4 I may try while I wait for my real material to show up.

    I've been working on the balance issue a lot. I got some weights for the parts with a bit of leg work. I went to a little store here called "Real Guitars". They were kind enough to let me bring my gram scale in and weigh pickups, etc. They also have a '63 ES-335 hanging on the wall. They wanted $16k for it and it wasn't pristine or 100% original (maybe 98.5%).

    On the way back to the shop I stopped by WD. I hadn't been in their place since they moved in a couple or three years ago. This is where they make the pick guards and where they ship internet orders from for all the stuff they carry. I picked up a TonePros System II bridge and tailpiece set and a three-way toggle switch. I'll get my tuners from them too -- Kluson's top of the line set. They were very nice, very helpful and offered a nice discount to me, I guess because I'm a local. Very local actually, they're less less than a mile from the shop.

    So, armed with real weights for many of the parts I figured the total weight to be around 7 lbs and the balance is close to what my CV in relation to the neck's scale length. One thought occurred to me -- does a neck heavy guitar feel that way all the time or mainly when played standing with a strap? The position of the strap buttons has a lot to do with the feel when you're playing on stage. Maybe I should have asked to nice guy at Real Guitars if I could take the $16K ES-335 off the wall in measure it's CG. Nah......

    ............Bill

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    Test Horn Almost Ready to Weld

    I have been busy doing design and tool development. This post will cover the test parts produced during the tool development. I'll cover the design work in a separate post.


    This is a shot of the three parts that will make up the test horn. The real parts will be similar, just bigger and more complete. The rim is bigger than it needs to be for this test, it will get trimmed soon. One horn panel has the edge rolled to meet the rim, the other hasn't been done yet. All the parts will require a bit of trimming at the mating edges.


    The rim, looking at the inside.


    And looking at the outside. This part is nice, I like the shape. Can't wait to do the full part!


    This is what it looks like on the form block. It holds it's shape well after the edge is rolled.


    This one is raised about the right amount. It's edge needs to be brought down to the form block. One thing I tried here was to run the part through my bead roller to put a break feature in where the panel goes flat. What it mostly did was score the surface and I may not be able to dress out the score. I won't do that again.


    This one probably has a little too much shape. I'll know more after I weld, dress and polish. I did the edge roll on this one just hanging on to the part by hand but it wanted to move around while I was beating on it. I'll try making a clamp bar that follows the shape of the outline and sits on the part of the panel that is supposed to be flat. That should make the edge roll much easier.

    The next step after rolling the edge is to trim so the parts mate correctly. Any gaps will tend to allow more shrinkage during welding. I drew lines in the center of the radii on the form block to help with the trimming. I hope to get these parts tacked together today.........Bill

  33. #33
    Forum Member Gris's Avatar
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    Re: Aluminum Archtop Build

    This is starting to look Dan/Silvertone-ish... Seriously, you are doing stuff I can only dream about - sooooooooo cool. Keep us posted!

  34. #34
    Forum Member Offshore Angler's Avatar
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    Re: Aluminum Archtop Build

    Now, if you really had a set you'd make that center piece out of Magnesium. :)

    And if you don't engine turn the back of the guitar before you polish it I'll disown you.

    LOL!

    All kidding aside, are you using consumable electrode? If you TIG it you are my hero forever.
    "No harmonic knowledge, no sense of time, a ghastly tone, unskilled vibrato, and so on. Chuck is one of the worst guitar players I know" -Gravity Jim

  35. #35
    Forum Member clayville's Avatar
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    Re: Aluminum Archtop Build

    I'm enjoying following your progress, but have a couple of questions about support at stress points that don't "seem" to be covered:
    1) Strap pins
    2) input jack

    Looks to my untrained eye like the braces headed toward the end pin are more about keeping the top/back from caving in than about shoring up the end pin... but maybe they do both.

    On the input jack area, the way it looks in the CAD diagram (unsupported?) seems to be a fairly fatal weakness to me. Bang it, or step on your cord and the whole thing could rip out or bend. But what do I know?

    FWIW, my CS-356 has the jack on the rim (sort of Tele-like, without the flatness) rather than sticking out of the top and I prefer that location by far to the top straight-out option that many guitars in this body style have. Just my two-cents.

  36. #36
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    Re: Aluminum Archtop Build

    Quote Originally Posted by Offshore Angler View Post
    Now, if you really had a set you'd make that center piece out of Magnesium. :)
    Sorry, the aluminum is already here.

    Quote Originally Posted by Offshore Angler View Post
    And if you don't engine turn the back of the guitar before you polish it I'll disown you.

    LOL!
    Every time I've done that (on flat aluminum!) I was disappointed with the results. It would look really cool though.

    Quote Originally Posted by Offshore Angler View Post
    All kidding aside, are you using consumable electrode? If you TIG it you are my hero forever.
    I've never used a MIG machine. My dad had a stick welder in the '60s and then I graduated the oxy-acetylene for aircraft welding. Once I learned TIG there was no going back. It's so easy to control the heat and welding aluminum is easy once you get the hang of it (clean metal, proper joint design and patience)...........Bill

  37. #37
    Forum Member Offshore Angler's Avatar
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    Re: Aluminum Archtop Build

    Dude, at one time I had to qualify for MIL-STD1595 for welding on missles. Of course, I was the stupid engineer and never would actually have to do any welding, but I had to be certified. What a pain that was. We had to fuse aluminum, and then the sample was cross-sectioned and examined under a microscope. I learned how to do the sample and that was all I ever did. But man, I had some guys that could lay down a bead you wouldn't think possible with a tungsten electrode. Definitley more art than science. I really respect guys that can weld well.

    Ah, the old chrome-molly normalized weld. To bad we had to cover all that with Stitts or Ceconite so nobody could see it.
    "No harmonic knowledge, no sense of time, a ghastly tone, unskilled vibrato, and so on. Chuck is one of the worst guitar players I know" -Gravity Jim

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    Re: Aluminum Archtop Build

    Quote Originally Posted by clayville View Post
    I'm enjoying following your progress, but have a couple of questions about support at stress points that don't "seem" to be covered:
    1) Strap pins
    2) input jack

    Looks to my untrained eye like the braces headed toward the end pin are more about keeping the top/back from caving in than about shoring up the end pin... but maybe they do both.
    Very good questions. Thanks for the input!

    I was more worried about supporting the top and back when I was going to use .050" material. The .0625" material is very stiff when it has a compound curve shape so I'm not so concerned about dents, etc. As for the endpin, yes, the braces do both. They join together and are bonded to the rim during assembly. The whole stack is almost 1/4" thick where the screw goes. I'm using a machine screw with a washer and stop nut, not a sheet metal screw. I feel pretty good about it. Here's an image;




    Quote Originally Posted by clayville View Post
    On the input jack area, the way it looks in the CAD diagram (unsupported?) seems to be a fairly fatal weakness to me. Bang it, or step on your cord and the whole thing could rip out or bend. But what do I know?

    FWIW, my CS-356 has the jack on the rim ... I prefer that location by far to the top straight-out option that many guitars in this body style have. Just my two-cents.
    Yes, I have concerns about the jack. It's shown as per 335 specs but I have no issue with a Tele-like location. I can bond a doubler inside the rim where it mounts. It's possible to do that in it's standard location but it might just spread the damage over a larger area. If the rim got tweaked a little, it wouldn't be as noticeable. Most times, the cable would just pull out of the jack if it's mounted on the rim -- with no damage. Maybe I need a break-away cable ..............Bill

  39. #39
    Forum Member clayville's Avatar
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    Re: Aluminum Archtop Build

    Again, just my two cents... the double thickness end-pin is reassuring, but when "worn" in the usual manner (hanging off a strap) there's sure a lot of lateral (upward) stress on the pin -- hence the long screws on a wooden solidbody, and the small blocks on a semi-hollow at both the end and horn pin points. It looks very strong re: pulling out, but maybe not so much against pulling up -- without a really strong barrel and a washer it still might be a sort of pivot point (if that makes any sense).

    Quote Originally Posted by cwilliamrose View Post
    Yes, I have concerns about the jack. It's shown as per 335 specs but I have no issue with a Tele-like location. ... Most times, the cable would just pull out of the jack if it's mounted on the rim -- with no damage.
    I think (based on almost nothing) that the double-thickness and rim location would be fine for the cord. Plus, to me, that's functionally preferable.

  40. #40
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    Re: Aluminum Archtop Build

    The one thing I can do that isn't so easy in wood is tighten the screw without fear of stripping the wooden threads. I can also use a larger screw than standard by modifying or making my own strap button. If the fastener is tight, almost all the loads are shear loads. That includes the screw, the rim, the brace plates and the bond joint. There's a small moment due to the strap being away from the rim because of the way the strap button is designed. That moment is probably less than 1/4". So, if you put enough load on the strap to fail the strap (let's say 100 lbs), there's only 25 in/lbs on the button. I can't imagine that being a problem with .220" of aluminum thickness. Maybe Chuck will have a different way to look at it??

    The other thing that might happen in that area is there may be a counterweight attached to that screw (inside the body) to adjust balance.

    While on the subject of strap buttons, do you have a preference for the location of the other one? A 3xx Gibson has it mounted on the heel under the body. Most guitars have the other button on the horn. The heel location is stronger but mounting it on the horn could be pretty strong if done carefully. I could even do a test with my horn section after it's finished. I would think a 100 lb load is a conservative number to use -- it would be like lifting a 200 lb person off the ground with the guitar while they hold on to the strap..........Bill

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