Headless Electric Manta Shaped Guitar With Plain Tuners

I got strings and new tools for Christmas, so I had to build another guitar.

This is my take on a 6 string electric headless guitar.

I let imagination lead the build, so it is probably not the best way to build a guitar, but it works, and you don't need too many expensive tools to do it this way.

Supplies

This is what I used, mostly brandless items from ebay.
String lock nut: 5$
Nut. 1.5$
Bridge: 8$
Truss rod: 460mm two way: 5$
Frets: set of 24 2.2mm, 5$
Tuners: Les Paul style, 16$
3-way pickup selector switch: 3$
Pickups: Prewired with volume and tone pots and 1/4" jack, 12$
Fret markers: 6mm acrylic 1.5$, 1.45mm side markers 0.1$
Strings: 11-50 gauge, Christmas present
Wood: free tables announced on internet, birch for the front, unknown redder Italian wood on the back and neck.

Step 1: Design and Measurements

I like to draw the design directly on the wood and be precise and accurate only where it is needed.

Start with a center line which everything aligns to.

Choose a scale length, that is the distance from the bridge to the nut, I went with 64cm/25.5" which is quite normal.
If you want 24 frets, 2 full octaves of notes on the strings, fret 24 will be exactly 48cm from the nut.
I marked those on the center line and placed my hardware around too see where it would fit.
I had some normal Les Paul style tuners, so I tried to find a way to use them.
Leaving a triangular headstock-like part of the body behind the bridge seemed it could work, even making it possible to let the strings go in a straight line all the way to the tuners.

But wait, did I just draw the shape I have been looking for in a guitar, the shape of my favorite animal, the Manta Ray? Guess I have to make another guitar, which is not headless, where this shape can go all the way through the guitar body.

I drilled some holes outside the outline of the guitar and cut the rough shape of the guitar, to be able to draw the shape on the back as well.
I drilled holes for the tuners, so I could use them as a reference at the back.
I also extended the center line all the way through.
I drew half of the shape on a piece of card board, so I could mirror the shape around the center line.

Step 2: Making Cavities for Tuners, Pickups and Controls

The tuners dictated a thickness of the body I had to leave for the "head/tail stock".
A chisel does this job quite effectively, when it is sharp.
Holes are drilled, saw between the holes and file to the desired shape.

All there tools are capable of tearing out fibers from the wood and chipping off bits at the edges.
It can all be fixed, it is a part of the process to mess up and fix up.
Not to worry too much about mistakes, as you see I make here.

My pickups has a cover, letting the cavity have some tolerance, which is pleasant.
I drill holes all the way through the body, since the body will be thicker by gluing more material to the back later.

Placing the controls and jack on the front, leaving a proper amount of wall to the outer part of the guitar, decides where I can drill holes for the potentiometers, the jack and the 3-way switch.
They all have different hole diameters and requirements on material thickness, so a lot of measuring and testing needs to be done while chiseling out the control cavity.

Grooves for the pickup wires are cut into the body to be able to route them flush with the wood.

Step 3: Mounting the Electronics

What, already? Yep, I am using cheap parts and does not have long experience in building guitars, so instead of a control cavity with a lid you can open, I plan to glue it all shut. If I want to improve the thing, I'll make a new guitar instead.
Probably not good advice, make a lid if you would like to be able to get to the components, but this results in a cleaner back of the guitar.

I mounted the pickups in the body, routing all the electronics out the back.

My pickups came with volume, tone pots and jacks prewired, so I cut both the jacks off, mounted all the pots and one of the jacks.
The front lug of the 3-way switch goes to the hot (red) wire of the neck pickup, the rear lug is soldered to the hot wire of the bridge pickup. The mid lug goes to the positive (red) wire on the jack.
This way, the neck pickup is working when the switch is pointing forwards, the bridge pickup is working when the switch points backwards and both works when in the mid position.

The ground wires (black or without isolation) from both pickups and the jack are soldered to the ground lug of the switch. I also added 2 extra ground wires, one to ground the bridge and one to a piece of aluminum that previously was used as shielding in a power supply.
This is my take on shielding the control cavity.
It was covered in electrical tape, to avoid any shorts that would be difficult to get to.

Test the pickups by connecting an amplifier an touch the pickups gently with a piece of metal.

This is the moment I should have wondered if the 2 poles behind the pickup cover need be exposed to work properly :-o
It would have been easier to drill holes in the cover at this point, rather then after the pickup wires are glued stuck.

Step 4: Add Thickness to the Body

Draw the body shape onto another piece of table, to get the proper thickness, and seal off the internals.
40 mm seemed proper for the widest part around the controls. The original table was 29mm thick.

2 items stick out of the body, the 1/4" jack and the 3-way switch.
These needs recess in the bottom plate at the correct position. Not too hard to do, since there are some wiggle-room and you feel it when the recess is big enough.

Both surfaces are sanded even and free of old lacquer before glued together.

Cut the bottom plate to the same shape as the top, no worry about the tears on the far bottom, quite a bit of thickness will be removed there anyway.

Since you cannot lay the guitar up side down on a flat surface anymore, due to the pickups and controls sticking out on the surface, I made a jig it could lay in and be fastened to my work bench.

I have a hand held machine planer that took off quite a lot of material quite fast, leaving a very rough surface.
The back was evened with a planer and with a wooden file.

I now started to shape the sides, keeping the edges round to avoid more tearing.

Step 5: The Fret Board

The neck will be made of 2 pieces, with a truss rod in the middle.
The truss rod turned out to be redundant, I did not need to tighten it at all, but I did not anticipate that.

The cross bar of my table had the hardest wood with the narrowest grain, so that would be the fret board.
I cut it in half, and used my machine planer again to get the thickness down to 10mm.
The other part of the cross bar is perfect as a sanding block to make the surfaces plain and even.

The fret board tapers from 40mm at the nut to 60mm. The length needs to be the distance from the nut (fret 0 if you have that) to fret 24 + some material in both ends.

The shape of my string holder dictates the truss rod to lie a few mm into the fret board, so I made a groove the width of the truss rod and a notch for the string holder to be mounted on.

Step 6: The Neck

Another part of the table with the wood grain parallel to the strings was sanded flat and even, preparing for gluing to the fretboard.

Most of the truss rod will be within this part, so a groove the width of the truss rod is carved here as well.
A caliper is handy to get the right depth.
When the truss rod fits inside the 2 pieces, it is ready to glue together.
Not too much glue on the truss rod, it is better the easier it can move.
My truss rod slid a bit too far against the end of the neck, without me noticing, could have been a good thing to double check before the glue hardened, but it turned out a persuasive whack seated it just fine again.

Now the decision on neck shape can be taken.
I was afraid to take too much off the height at the end, so I carved the string holder into the material and kept it quite thick for now.

I machine planed the height and width to a square I could shape further shape by planer and file.
A good neck thickness is tapering from 23mm at the nut to 27mm where it meets the body.

I start with a U-shaped neck, thinking I can go back and make it more V-shaped later if that feels more comfortable.

After filing the rough shape, I sanded the rest using 80 grit sandpaper with and without a sanding block.

I know now the exact position of the nut, and can cut the neck at 49cm, 10mm from the last fret.

Step 7: Frets and Fret Markers

Now it is time for the frets.
I use the fret calculator on www.monsterbass.nl to get the exact distances from the nut to the frets.
Since the neck isn't rectangular, I mark the distances on both sides of the neck.

I had round fret markers, so I drilled holes the same width and depth as the markers, fastening them with wood glue and a whack with a rubber hammer.
Similar approach with side markers.

When cutting slots for the frets, I steady the sawblade with a finger on each end, making it possible to get a reasonably accurate (ish) cut.

Before you start inserting the frets, sand the fret markers flush, way easier before the frets are installed.

Frets can be pressed into the fretboard if you have a drill press, I don't so I use a small rubber fret hammer.

I add a little dab of superglue at the fret ends, to make sure the will not fall out. Probably not necessary, but comforts an anxious soul.

Frets that stick out on the sides are snipped off with a side cutter, and the ends are filed round.

Step 8: Fret Work

Fret work is messy, add masking tape between all the frets to protect the fretboard from metal shavings and careless filing.

If the neck is not completely flat, the truss rod can be used to straighten it before you start.

High frets are located with a short straight ruler, and firstly given good whacks with the fret hammer, to see if they were not seated properly. If that does not help, a metal file is used on the fret to make the height in line with the surrounding frets.

Add color to the top of all the frets and then sand all the frets simultaneously with a long straight ruler, until all frets have sanded the color off the top.
Your frets should be level now.

The frets (specially the ones that was high) are now flatter on the top.
A fret crowning file can be used to get the shape back, but you can also use a small triangular file and hand-file the sides of the frets until you see they aren't flat on the top anymore.

I tried to use a fretboard protector on top of the masking tape, but that did not work, it was way too thick. Either or, looks to work.

Use a small triangular file to carefully round the ends in all directions.

Step 9: Fitting the Neck to the Body

Seeing that the end of the neck was a good way from perfect, I marked exactly 49 cm again and filed it down, making sure to always have the edges round. Not the time for more tears on the edges.

I have a laser that I used to light a line along the body and the neck to mark where the neck should be carved into the body.
I drew a line around the neck so I could get a perfectly positioned neck pocket.

I marked with a piece of tape the depth the neck should have into the body, making it rise 7mm above the body.
Then drilled a lot of holes, making the process of chiseling out the neck pocket quite easy.

I intentionally made it narrow, and test-fitted the neck regularly.
The amount of material on one of the sides was not enough to hold the neck, so it broke off.
The guitar made a design decision by it self and the body now is straight and not curved against the neck, Ok.

With the neck finally in its correct depth, time to verify the position with the laser again, disastrously way off, something went wrong in the marking phase.

Time to clean up the mess.

Step 10: Clean Up the Mess

If you did not mess up, skip this step.

The neck was fastened with two screws, so I removed one of them, pivoting on the other until the backend of the guitar, the bridge, the pickups and the mid of both the ends of the neck aligned.
I added another screw to fasten it in it's final position.

As you can see from the first picture, it was really way off.

I sanded a small wedge to fill most of the gap towards the pickups, this is the direction where it is crucial not to have any wiggly play.
Then I made filler by mixing sawdust and wood glue.
I filled the gap with the filler and pressed the wedge in towards the neck, that had got a cling film wrapping to avoid it being glued in place.

The glue was hardened over night before the neck was screwed loose, allowing the hardening process to be faster with the cling film gone.

Step 11: Final Shaping

With everything attached in it final place, it is time to make the shape rounder where you want it to.
I used a rough file, almost like a rasp to remove most material, a finer wood file to get rid of the rough surface made by the rough file.

Then 80 grit sandpaper, with round or flat sanding blocks where appropriate, no block for the hard to reach spots.
120 grit sandpaper fill get rid of all the small tears and grooves.
Big ones might need filling, or a whole lot of sanding.
150 grit was my final finish, removing the scratches and unevenness of all the previous steps.
You might want to carry on for a nicer result, but I was satisfied here.

I put on a coat of linseed oil to protect it when taking it out to the camp fire gatherings.

Step 12: Mounting the Rest of the Hardware

Home stretch now.

The ground wire for the bridge is dismantled and the end is tucked into one of the bridges screw holes.

Screw the bridge in place and adjust the distance to be exactly 64 cm.

Tuner are fastened by the lock screws in holes premade by a small awl.

The string holder is mounted in predrilled holes.

The nut is a bit high, so it is lowered into the neck by first cutting a small groove with saw and chisel, then filing it the last tenths of a mm with a square file.
The string height should just be a little bit above the first fret, making it easy to play.

The strings are wound on the tuners, you then see the string height all the way, and can adjust it at the bridge.

The truss rod can also adjust the string height on the middle of the string if the neck bends.
Mine didn't, so I just tightened it enough to keep it from rattling.

Add a couple of strap screws to be able to use it with a strap.

I use a phone app to help me tune the strings.

Check the intonation by tuning the string without touching it, verify that it is the same note one octave higher at the 12th fret, and 2 octaves higher at the 24th fret.
If the note is lower, the string is too long, and you can adjust the position where the string lies on the bridge by loosing the screws on the bridge.
Tune again until all 3 notes are the same.

I think we're done :-)