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Acoustic archtop build

(Completed 2014)

For a long time I have considered building an acoustic archtop guitar, they are quite specialised and almost always associated with jazz. I have to confess to not being a huge fan of that genre of music but I do love the shape of the guitars. In addition my main work has always been solid body electrics so I was quite excited at the thought of building an acoustic, not only that but with a carved top and back.


Taking on a project like this definitely needed a lot of reading before bringing a saw to bear on any pieces of wood! There is a lot of information on the web but I decided to buy the 'bible' for the archtop builder and that's Bob Benedetto's book imaginatively named "How to build an Archtop guitar". I don't think it would be possible to build one of these without a book like this and I read it from cover to cover before even deciding whether I was capable of building one.


Anyhow I decided it was possible and planned to build it alongside my paying work on a sort of piecemeal schedule, it was certainly not going to be the type of job I was going to do if I didn't feel in the mood!

Before the build pictures.... Here's a taster of the completed guitar....


So first off I made a list of all the wood I needed:-


Book matched Engleman Spruce top
Book matched Quilted Maple back
Two piece Sycamore (aka European maple) neck
Ebony fret board.
And a 'lump' of Engleman spruce to make the various other parts, internal braces and blocks etc, I ordered this from various places, some from Canada and some from the UK.
For this type of guitar it is necessary to build a number of jigs, although one aspect of the book that is not very helpful for the DIY builder is the number of specialist tools and jigs that are used, buying or making all of these for an essentially one off project is not practical.. But some of them are a must.

Here's the majority of jigs I built. They are mainly of good quality ply or MDF. In the foreground is the thickness measuring caliper for carving the top and back, then to the left is the arch carving templates, the two clamping cauls for the top and back which double up as cradles for carving them, then there's the 'mould' for making the body sides, the neck dovetail routing jig and standing up at the back is just a thin template for marking out the shape of the body..... And getting ahead of ourselves a bit here is also the carved top.

Here we are in my cramped shed using my new ebay acquired planner/jointer although this is much more useful for jointing solid body guitars, the relatively thin wood for the top and back of an archtop could easily be done with a hand plane. Nice quilted maple though!

 

Gluing and clamping the back, notice the top also joined and glued.

Here we are starting to carve the top, I couldn't think of any easy way to do this, I'm using a Safe-T Planner in my drill press, really it was just a case of using whatever felt right.

Difficult to see, but here I've kind of carved some 'trenches' in the top close to the required contours, now I can work on getting the rest carved.

 

Pretty much there with the outside of the top, notice my tiny thumb plane which was a really useful purchase.

 

The archtop now pretty close to the templates, the carving can't be finished until the body is more or less complete. Around the edge of the top and back is an area called the recurve, this is a 'trough' carved about a inch or so in from the edge. The recurve gives the top and back a nodal point to aid its vibration and hence sound. You can see how the MDF templates just sit proud of the top as the recurve is carved they should fit snug to the surface.

Here I'm starting the most laborious part of the build, carving the inside surface of the top and back, the principle here is to use a drill press, place a peg on the base of the press directly under the drill bit, adjust the stop on the drill such that the drill stops about 3/8ths inch from the top of the peg. Now balance the top on the peg, moving it around and drill about a 1000 holes!!! A couple of things to be careful here are; a) to make sure the drill bit is tight in the chuck and.... b)I used a Frostner bit as I didn't want to risk having the drill bit 'grab' the top or back and pull it up the drill off the peg.

 

Just for a change here's the inside of the back being carved, after the holes were drilled. Carving the Maple is a LOT harder than the soft Spruce top, be prepared for many hours carving and a VERY sore thumb!

Finally getting on with more pleasing jobs after the top and back are carved. After careful marking out I used a fret saw to cut the 'F' holes. Although I want the guitar to be, in the main traditional, I still want my own "stamp" on it and I want to make it look a bit Art Deco so decided to try aluminium binding. Here you can see I've made an 'F' hole template to bend the Aluminium around before gluing it in the holes.

Starting the bracing, I decided on X bracing, you have a choice of parallel or X, the latter is meant to give a brighter sound, although its all a bit subjective, from an engineering point of view I felt the X was stronger.

Here we go marking one of the braces.

Cutting the brace profile.

Just about ready to glue in..After some sanding for a tight fit to the top.

Yeah I know the clamps are a bit excessive! but they were only £1.95 each! and do the job really well!

So here we have the top finished until it gets joined on to the sides.

 

 

Starting the sides, these are flamed maple and sanded to 3/32 thick, I haven't got a thickness sander to do a job like this so I purchased the sides ready thicknessed (Stewart McDonald). So here I am cutting them to depth, the whole guitar needs to be 3 inches deep so the sides are cut to 2-5/8ths.

 

Something I'd never done before, the technique is to soak the wood for about half an hour first then bend it over a hot pipe, I had read on the internet how to do this, the key point seemed to be that you must get the wood steaming hot.

I had a piece of copper pipe laying around, so as you can see rather crudely I heated it with a propane blow torch, kept wetting the wood and rocked it over the hot pipe until it became a bit 'plasticy' then bent it to the curve.

 

Here's the secret to getting an accurate shape, One of my jigs for making the guitar is this mould or template to hold the sides, its important while the sides are still soft from the bending procedure to place them in the mould and clamp them up and leave them overnight. This picture shows a before and after. One side has been in the mould and the other finished. I must admit this part of the job proved very satisfying. As you can see there are a few minor scorch marks but these will easily sand out.

 

Here's the neck block gluing in place.

...and the tail block, both are spruce, it is really important to get the centre join on the sides perfect, I've placed a piece of thin polythene between the mould and the join to stop it sticking to the mould

Hey! Something's beginning to look like a guitar!!! Just trying the sides on the front.. one thing I did 'catch while doing the sides is to be careful of your right and left, the maple sides have quite a flame that is more set to one edge of the wood than the other, I must have had a clear mind that day since I was careful to match the orientation from one side to the other.... something I would have normally missed!

You can see in this picture that I've carved the top plate braces, these have to be profiled into a bit of a curve to match the top.

 

Quite an easy job, here are the purflings being glued in, the additional thin strips are to give the sides strength and prevent any splitting, placed at 4inch centres as advised in the book.

 

Just some more detail shots... I was a bit annoyed with some of the clamping marks, this I think was due to the wood being wet and not having enough hands to hold everything, I know they won't be visible once everything is built but that's not the point!

 

 

Neck block stuck in....

 

Here we go gluing the top to the sides underneath I used a clamping caul that I had made, see the templates picture. Those wooden clamps have been handy and a drill vice!

Top glued on....you can see that I carved the top a bit enthusiastically under the neck block and had to add a bit under the corner.

 

 

Gluing the back on using clamping cauls.

Here's the body really beginning to take shape, final shaping of the top can be done once the binding has been put on.... I'm thinking on this one, since as with the 'F' holes I want to use aluminium but at the moment I'm having difficulty finding strip the correct dimensions.

And the back, trimming the edges was not an easy job and took ages, no fast way just patience, files, spoke shave and sand paper.

On to the neck. Due to the availability of a gorgeous piece of Sycamore (European maple) I decided to go for a two piece neck....You'll see the grain later!

A lot of clamps!...Sticking the two neck halves together.

Using the planer again to get the fretboard and peghead surface flat, I did this on the floor with the dustbin wedged against the planer outlet, saves a lot of cleaning up!

Here's the planned surface which shows the lovely flame in the grain, I'm looking forward to lacquering this to see the full effect of the grain.

Routing the truss rod slot.

And the truss rod in place. I prefer using the aluminium channel style rods as they are self contained and don't require any work to anchor them.

The neck set up in the jig to cut the dovetail body joint, my jig wasn't quite right but some fiddling and care setting it up for the 41/2 degree angle made it ok.

A look at the finished result in the jig, quite a relief to get the end result looking good.

And here it is, I had thought of cutting it by hand, but I was worried about getting the area at the base of the dovetail flat so there would be a perfect join with the body. In the end making the jig didn't take that long, lets hope cutting the body end of the join will be as successful!

 

Here's the Jig for cutting the body end of the dove tail, as you can see I've used one of the carving cradles/clamping cauls to mount the body to a flat surface and then screwed another piece of wood to the top at right angles, this has the hole/guide to cut the dove tail slot

 

Hardly dramatic but this is the end result, it's well worth taking a great deal of time to make sure that the body is lined up perfectly for this cut, the centre line of the neck and body must line up.

Simple job of cutting the rebate in the end of the neck for the neck extension that continues over the body, the neck joins the body at 14th fret.

Gluing the neck extension on, I used 'folding' wedges behind the clamp in the foreground to apply pressure to push the neck extension into the neck.

 

 

Here we are starting to cut the rebates for the binding around the body, I used the ever versatile Dremel with the Stewmac router base, the only thing I had to do was make a smaller base such that it wouldn't interfere with the arch and upset the routing, I wasn't over the moon with the result but it was ok.

 

Gluing the binding on...ugh my least favourite job as I don't feel I have ever found a method that I'm totally happy with, here, as can be seen I've made a 'peg board' and used wedges to hold the binding in place. If someone knows the best glue to use for sticking the binding please let me know, I've tried all sorts from super glues to Araldite as here, Araldite sticks ok but is very messy....Oh well the job gets done.

Well after a LONG break, probably a good 2 years, I'm back to this project. As well as keeping up with my paying work, I've done a few other projects, but now I've decided to press on with my unfinished stuff. It's not that I ever intended to do this archtop in one go, it needs thinking about, both design and build wise, and I keep changing my mind on how I want the end result to look, basically I want something traditional but having some of my own design features.

Beginning the work again wasn't as bad as I thought, thankfully I'd stopped at a "logical" point in the build so I was restarting on a fresh page so to speak. The fretboard is ebony with a 25 inch scale length, as described in the book, fortunately the Stewmac fret ruler has this scale marked on it. I made a simple mitre box to cut shallow fret slots, the tape is on there just to help me see the marks. Here the picture shows the slotted blank ready to be glued on the neck. I've made some crude jigs to locate the fretboard, more often than not when gluing, the parts will slide around a bit so this will hold everything in place. Have a read a couple of pictures down regarding the width of the fretboard.

Gluing the fingerboard on. A while ago I changed my mind on what glue I use, I used to use Titebond traditional wood glue but this is water based and has on occasions caused the neck to bend into a back bow due to it wetting the surface of the neck, so now I use a twin pack epoxy, it's far more messy but avoids the risk of bending.

All stuck down. I decided to go for a simple layout with single binding and pearl dots, rather than complicated inlays and multi bindings, as I have designs on fancier stuff elsewhere. The width of the fretboard is obviously crucial and ultimately depends on the neck joint, if everything has gone to plan half the width of the fretboard at the fret over the body joint (14th fret in this case) should be the distance from the top plate centre line join to the edge of the body in the cut away/neck heal and this distance has to include the fretboard binding. The nut width can be varied to playing tastes but the width at the 14th fret is fixed, minor imperfections can be sanded out on the neck heel or body, but bare in mind that the body sides are only a couple of mm thick, so best get it as close as you can, plenty of trial fitting and lots of measuring!

I shaped the fretboard starting with a plane, this has to be razor sharp for ebony as it has a tendency to chip, once the radius (12 inches) was close I finish off with a radiused sanding block and a long straight edge to make sure it's PERFECTLY flat. At this point I cut the fret slots to the final depth. Some people advocate building the fretboard to a finished state before gluing it on the neck. In no way am I suggesting this is wrong, but I prefer to build it on the neck as I can ensure that it's going to be flat. There are pros and cons with both so I guess it's just a case of picking your preferred method.

My two year break has taught me something, and that's how to best fit plastic bindings! I wish I could turn back time and re do the body. Firstly I meticulously cleaned the edges of the fretboard and paint a layer of thinned down wood glue on and wipe it away, this seals the wood, then I glue the binding on with super glue, this way you don't have to clamp anything. Stick the first couple of inches on and then work along "wicking" glue in as you go.

Beginning the fret work. Just a note here on fret slots. Ebony is VERY hard and if you don't get the fret slots correct it can be a real bugger to make a neat job. Firstly and obviously the slots have to be deep enough it is also well worth running a triangular file over the slots just to give a little ramp to ease the way for the frets, also it allows the frets to sit tight to the fretboard surface, and MOST IMPORTANTLY the fret slots have to be clean.

One of the problems with binding is that some of the glue can wick into the slot, so spend some time cleaning the ends of the slot either with a modeling knife or a fret cutting saw.

Anyhow, in this picture you can see that I'm using a proprietary tool for nipping the fret tang off to allow the ends to sit over the binding.

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..And pressing in the frets, this is where it would have been a lot easier if I had built the fretboard separately. I could use the press for most of the frets but had to hammer some in. But no real problems, like I say make sure those fret slots are perfect.

 

The headstock cut to shape. I made a template of half the shape and marked it on the headstock, then flipped it over such that it was symmetrical, then cut it out on the bandsaw, a slight error here, this should really have been done before the fretboard had been fitted as I could have cut it out upside-down flat on the bandsaw bed, not a serious problem but something that I should have thought of.

No fancy tricks here, when I get to this stage building a neck I prefer to do the shaping by hand, it may take longer than routers or bandsaws to take the excess wood off but one small slip could lead to a ruined neck, so I'll stick to my spoke shave and files. At this point the book advocates building a cradle to hold the neck for shaping, for a one off that seemed a little excessive to me so I just clamped it to my bench by the headstock and got to work. before I started this I'd filed the fret ends down flush with the fretboard edge and cut the neck width roughly down within a couple of mm of the fretboard edge.

Due to the radius of the curves at either end of the neck a spoke shave won't work and really I think that using any method that suits works best. I find that a sanding drum in my drill press is very handy, but be careful as it's very easy to take too much off, don't just concentrate on the area you're sanding, keep an eye on the shape of the whole neck and frequently run your fingers over it, believe me they're the best measuring instruments you have!

Here I am sanding the curve around the heel of the neck, again the same procedure as above, take care! There's only so far you can go before you have to resort to finer tools for shaping, files, chisels and sand paper. The profile of the neck is quite a personal choice, I would suggest that if you have a neck that you like then copy that, although I'd steer away from anything too thin. The more usual profile for this type of guitar is half-round.

 

I have to say that I've always enjoyed shaping neck profiles, it's very satisfying as it's about the first time in a build that you can imagine playing the guitar. It's important to get it right, take lots of time shaping the the neck as it runs into the heel and the headstock, I always think that a nice shape around these areas always shows quality. It takes me around 3 hours to get the back profile to this stage. As I have to fit the neck to the body, I'll leave the final sanding until then as I have to sand the body and neck together to get a smooth line.

This kind of came as a bit of a surprise, I suddenly realised that I could join the neck to the body and have something that looked quite a lot like a guitar! The body has had plenty of sanding done to it and a couple of coats of cellulose sanding sealer applied. Personally I prefer hand sanding and only in the direction of the grain, using electric sanders I find leaves a pattern on the wood that shows up once a finish has been applied, it's probably just me using incorrect grades of sand paper, but I'm going to stick to hand sanding.

And the quilted maple back, kind of wish I went for a flamed maple now. I thought at the time that I'd give quilted a try for a change but I have to say that I prefer book matched flamed.

Getting the dovetail joint perfect took about 4 hours, it says in the book that it must be a tight accurate fit on all the contact surfaces. I had quite a long discussion on an archtop building forum as I didn't understand the gluing process outlined in the book. Basically you only glue the flared faces of the dovetail and a blob of glue on the top plate, also you have to leave a space behind the dovetail. It's done this way so the neck can be removed should the angle need to be reset as the guitar ages. The process to remove the neck involves drilling a hole in the fretboard right at the back of the dovetail and injecting steam to soften the glue. No glue is applied to the face on the body. I guess, assuming that the dovetail is tight then the glue is almost superfluous.

Ah... One thing I didn't take a photo of is shaping the neck extension, I traced the profile of the body top onto the neck extension then cut it with my bandsaw, the underside should be a perfect fit to the body for the first inch then it needs to be cut with a small clearance to allow the top plate to vibrate.

Just a word to the inexperienced: You really DON'T want to be making any mistakes at this point, although this is my first archtop, it isn't the first guitar I've built. Believe me I've made several silly mistakes on simpler solid body guitars resulting in wood and time being wasted, not to mention the frustration. At this late stage measure twice and cut once.

Here's the dovetail ready to glue, adjusting the joint is just a case of putting it together and taking it apart a hundred times and scraping/shaving/sanding off fractions. At times I thought that I'd never get it right but eventually I got it perfect, a good trick is to use pencil lead wiped on one of the joining surfaces, then pressing the joint together, the lead is picked up on the high spots, highlighting the areas that need to be removed. I really wouldn't worry too much about the dovetail becoming loose it's very easy to add a thin veneer of wood to one or both sides of the joint and it doesn't compromise the strength at all.

Notice that the neck extension has been finish sanded, as there is little room to do the job once it's glued on.

And here we are gluing the neck to the body...At last! One other thing you shouldn't forget is that the centre line of the neck should be spot on with the centre line/joint line of the top plate, not just at the end of the fretboard but for the whole length of the guitar. If the dovetail is a bit loose you can shim it such that the neck can be pushed a fraction one way or the other but this won't fix any angular misalignment (in plan view), if that's the case then it's back to adjusting the dovetail.

This picture does highlight one problem that I had when making the body, initially I had bound the body with aluminium strip but after trying numerous glues I just couldn't get one to stick. Thus I went back to using the usual plastic, but the big problem I had was removing the glue that I'd used for the aluminium and this was a real tough job, unfortunately I damaged some of the wood removing it, hence there's the odd local patch of filler...Grrrr..So I'm going to have to count on the finish to cover these odd spots.

As I've said previously, I want to add my own design features to the guitar and go for something a bit art deco, so here's the "sun ray" headstock design. The black is ebony. Nothing very complicated here just time spent cutting pieces on the bandsaw, plenty of time sanding and a few paper templates, the black centre section is the truss rod cover and will be held in place by a screw.

I have to say that I wasn't in favour of veneering the headstock fully, for two reasons: One being that if you veneer the front face then you should also veneer the back, to prevent any chance of the headstock warping (as advised in the book). Personally I've never liked the look of the back being veneered, to my eye it looks too fussy and like the guitar has had a headstock repair. And second with a lovely flamed maple neck I don't see the point in hiding any of the grain.

I turned my attention to the tailpiece next, I had a few designs in my head and in the end went for something a bit art deco. Following advice from the Benedetto book I decided to use a cord attachment method rather than a screwed on style tailpiece. According to the book there's no hard and fast rules as to the shape, so I figured it was an opportunity for some individual styling.

I had thought of making the whole thing from aluminium but since the body binding didn't work out there seemed little point, so in the end I chose ebony, I had quite a thick fretboard blank laying around that was ideal. In the picture above I'm using my Dremel to cut the slots for the loop thingy that wraps around the end pin.

Here's the thing after hours of work, I have to say I'm not a fan of working with ebony, it's so messy, almost like coal dust. You can see my art deco sun ray pattern taking shape, a little filling is required to neaten-up some awkward corners, that's the one advantage of ebony, a little super glue and some sanding dust and the job is done! It took an age to get to this stage, something that was covered by a mere two pages in the book turned out to be a lot of work!

Sorry, poor photograph, I'll try and get a better one. Here's the carving underneath, the whole thing is curved to follow the curve of the strings and to keep it light I've hollowed out the back, also I haven't used the typical "key hole" slots for the string anchors, I don't know why but I don't think they look very nice, so I've drilled holes such that the strings can be threaded through from underneath, I may regret this as it could make it more difficult to change a broken string, we'll see how it works out over time.

Still some sanding to go, but at least you now get the picture of what I'm after looks wise. I know that this is going to be a pain to sand as the ebony dust will make the maple veneer dirty, I may resort to scraping instead.

The ebony bridge under construction, notice that I've kept the art deco shape going on the bridge feet. I've decided to go for an adjustable bridge, although the book suggests that a none adjustable would probably give a better sound, it's something I can easily change anyway. It takes quite a while to carve something like this, I mainly used my bandsaw and sanding drums in my drill press.

After gluing the neck on, I ended up with just over 3/4 inch clearance for the bridge. The book states that there should be 1 inch, although asking around on various forums 3/4 inch is perfectly acceptable plus I've got the height of the strings (action) to add.

Here it is thrown together for a picture, to give an idea of the style. I've been sanding the body on and off for a few days, but it's getting pretty close to spraying now.

At last, after what seemed an age of sanding I finally got the spraying done. It's all in nitro cellulose with hours of sanding between coats so the overall finish is as thin as possible. As I'd mentioned above, I had hoped to do a natural wood finish but the hiccups with the binding meant that I had to go for some kind of sunburst, initially I was pretty unhappy about this but after doing my Firebird guitar in a green burst I was quite excited at the prospect of repeating the finish on this archtop as I kind off think it's adds to the art deco look.

Here's a closer view, I did decide to change my technique to spray this burst, I sprayed the black edging first then the transparent green over the whole lot, this tones down the black and makes the whole effect a little more subtle. Although I have to confess that it took two attempts to get the black right, like I needed to do another days sanding!

After saying that I wasn't so keen on quilted maple, I'm quite a fan now! once I'd sprayed the green, after a couple of days and a very light sanding I overcoated the whole guitar with a couple of clear coats.... Before HOURS of flatting back and polishing. Not much more to do now, level the frets, get the bridge finished and set up, I say not a lot but this will take quite a while.

I was going to fit a pickup but I'm changing my mind on this, at the moment times are a bit tight and I only play at home so the guitar won't be used through an amp, I will however fit an end pin jack just in case. I'm having the same doubts about a pickguard, I was going to build one from ebony and maple in the same sort of sunray pattern as the tailpiece but I'm thinking that could be over doing it a bit. So I'm just going to finish it as it is and make my mind up later.

 

Finally with strings on! At some periods in this project I didn't think I'd ever see this day. It was, it was nice to have the time for a concerted effort to get the guitar finished.

I've still got some finishing off to do, but you can see in this picture the completed bridge, the string saddles are bent wire staples, with a series of holes drilled such that you can place the staples to adjust the intonation.

Most of the wood for this guitar I purchased from a guy in Canada and that was 5 years ago. Looking back at the pictures I can barely remember doing some of the stuff. I'm so pleased with the way its turned out and in some respects can't believe I built it! Some bits are far from perfect but I really don't think I'd have the will to build another one.

 

Closer shot of the body, nice flamed maple sides highlighted with the green. The Benedetto book was essential reading, I can't imagine being able to build one of these guitars without the guidance given in the book.

The headstock design probably won't be everyone's cup of tea but I'm pretty pleased with it, like I've said all along, I like twists on traditional designs, the centre strip can be removed for access to the truss rod.

The quilted maple back plate and flamed maple neck.

Completed November 2013.

 

 

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