Site hosted by Build your free website today!

F. Davies Classic Electric Guitar Construction Guide



The Neck.


The Neck

Select this piece with care, it is the heart of this instrument. Choose wood that has had time to dry and reach an equilibrium with your local humidity. Freshly cut wood may tend to warp as it dries and this would be disastrous if it warps after being made into a neck. The wood I selected had been drying for several years thus, any warping (which is the strain caused by the stress created from an uneven drying), has already taken place before I begin squareing the stock. This same piece will also become your headstock and fingerboard.

Grain should run the length of the board and the individual layers of wood should also run from front to back of the neck.
This will result in your neck having the greatest strength possible in support of the strings, and the least bending of the neck. (This is opposite of the desired effect of an archers bow from which stringed instruments originated and where flex is desireable.)

Here is a cross section of how this piece may have been cut from the log, and how four pieces may be cut from a single log.

Square the board true by machining all four sides and both ends. One face of this board will be the face of the fingerboard portion of the neck and should be treated respectfully so as to avoid scaring it through the processes. If a laminated headstock is desired or required (due to the available lumber sizes,) Then machine the surfaces to be joined, glue them, and then machine the stock back to square. For Cocabolo wood I use acetone to help clean the wood before joining with (ethyl) cyanoacrylic glue and waiting several days before unclamping.

Machining the neck.

  • Layout your cuts by marking (lightly drag) with a white, very sharp (sharp in the sense of creating lines a hundreth of an inch wide, and not in the sense of digging into the wood) pencil (I prefer Berol Prismacolor pencils.) directly on the stock. You will need to maintain reference points, edges, and surfaces to measure from so try to make all your measurements from the same starting point. As your stock should be square and accurately machined to the initial dimensions, you may select the face of the fingerboard as a plane to measure from. The sides of the stock should also be accurate and may also be used to measure from. Marking your cuts will keep you from making a gross error, but you should rely upon measurements for setting up the actual cut and use the marks as a visual confirmation the the cut is about to be made in the correct place.
  • Remove the material from the front of the tang leaving a shelf (from which you may measure toward the headstock.) Draw a line where the nut meets the fingerboard across the fingerboard indicating where the taper of the headstock will begin. Machine the groove for the nut, after measureing from the tang as you would normally do when machining and using the line you marked as a visual double check. (Place a precision piece of metal rod stock in the mill and using a piece of cellophane or a cigarette paper as a feeler gauge, bring the rod into contact with the edge of the stock so that it is just the thickness of the gauge away. Raise the bit and change it to the bit to be used for the nut groove. Move the milling machine table so that the bit will be ready to begin cutting by moving the thickness of the paper gauge (typically 0.001 in.), and the radius of your rod, and the distance to the nut groove, and half the distance of your bit, plus a smidgen more to place the bit near the center of the cut. You should be able to know exactly where the bit is at all times so that as you machine your groove you will be able move the table of the milling machine to work your way out from the center of a cut to the edges. The backlash of some machines will require you to periodically measure the width and depth as you are cutting to be precise. Your final passes should be removing 0.001 in. at a time to give best results, and you may notice that it may take several (spring) passes (without moving) before the bit stops cutting due to stresses in the bit amd machine.)
  • Machine the face of the headstock, then turn the piece over and machine the back of the headstock to the proper thickness, and parallel to the face.
  • Carefully mark the position of the holes and bore the three holes for the rollers of the tuners from the sides. It is advised that you attempt to be as accurate as possible and measure to the 1/1000th of an inch. It is also recommended that you place another piece of wood on the opposite side where the tool will break through to avoid splintering, or to machine the holes from each side instead of all the way across. Do not burn the wood with dull bits. Bevel the edge of the holes for proper clearance of the tuner parts. Check for proper fit and then drill the small screw holes which will later hold the tuners in. Use caution that you do not drill to deep and if possible use your milling machine to ensure the depth is correct. (If you drill to far, then the screw holes will show on the inside of the string stores, so be cautious as a depth of a quarter of an inch is all the way through!)
  • Clamp at an angle and then cutout the string ramps exactly as wide as the string stores will be.
  • Reclamp the stock to mill out the string stores. You should have noted that the cuts will have a better finish in one direction compared to the other direction of your milling. Mill in the direction (referenced to the rotation of the bit) which does not tend to splinter the wood, that is, mill so that the cutter is rotating the same way as the wood is moving as if the cutter were pulling itself into the wood. Use light cuts and repeated passes and as you approach your marks take the time to measure untill you are shaving just 0.001 inches in a pass. You may also cut the small notch at the top of the headstock for the inlay at this time as this will result in its being cut most accurately. Cut the end of the headstock also at this time. Using a special cutter, radius the three outside edges of the headstock and then do the same for the edges of the string stores with a smaller bit. Use caution so that you do not run the bit into the string ramp, and finish with a hand blending of this radius on the string ramp toward the nut where there is insufficient clearance to machine. Your headstock cuts should now be complete.
  • Clamp the neck flat on its fretboard (back of neck is up) and cut out the tang to its proper width and depth. Watch that you do not cut into the fretboard portion of the neck as the fretboard portion will need to remain wider than than the tang at one end.
  • Reclamp the neck to the proper angle for the neck's taper, and face the back of the neck to the proper thickness from the headstock to the shoulder just before the body. Make the additional scarf cuts (not to finished size) along the necks radius which will reduce the amount of hand work needed for the final smoothing of the neck. I strongly recommend working these cuts out on paper as well as marking the limits of the cuts on the stock to prevent the error of over cutting.
  • Flip the neck over and reclamp so that the side may be milled to the correct angle. Mill one side, then clamp to the angle required for the next side and make that cut as well.
  • As a finishing touch I like to mill a couple of spots to insert abalone dots on the side of the neck. I mark just the seventh and nineteenth frets in this manner. Glue in these dots as well as the headstock inlay at this time and let cure before proceeding to sand the neck in the next step.
  • Using files, belt sanders, and hand sanding and scrapping techniques, gently shape the back of the neck until it is perfectly radiused, using great care to ensure a smooth and straight gliding of the performers thumb in concert. I used a series of blocks shaped to the various proper radii and glued sandpaper to them and then sanded length wise to prevent dips and bumps. Heavy cardboard can be shaped to a proper radius and also used as a sanding block. Proceed slowly and methodically taking great care to make this as even, and as fluid a shape as possible, (as ANY perceivable imperfection will be a distraction to the performer.) You should work toward finer and finer sized sand paper as you progress, and end with 1000 grit paper. I prefer to use emery paper and wipe often with a damp cloth or sometimes a bit of acetone as this helps keep the surface clean and free from oils. You may elect to also sand or scrape the headstock to blend the area where headstock and neck merge and where the inlay was glued in. (The ends of the inlay should be blended to the same radius as the edge of the headstock and made level with the face of the headstock.)
  • Luthiers usually make straight cuts across the fretboard for the fretwire's tang to set into. This results in the ends of the fretwire's tang showing on the side of the neck. While this is okay with most, some (rarely on a classic guitar) add a layer of binding to cover this. Binding in this manner will require additional cuts to the neck where the binding will be and is non-traditional in a classic guitar. It is more acceptable to cut straight across and leave the ends visible than to hide the ends behind some binding. But there is a better solution. Simply make the cuts stop short of the edge of the neck and shape the ends of the tangs to fit. Use a milling machine or other accurate device to ensure that all cuts are precisely made whichever method you use. If you choose to follow the plan you will first need to construct a device to make these cuts as I did, or use a very small bit and great patience in milling slots just short of protruding through the side of the neck.
  • As a string is stretched when fretted, the action (height of the strings) must be taken into account in determining the placement of frets. An action which is high will result in a string stretching more thus sounding sharp (at a slightly higher pitch.) Lower action than normal will result in the opposite effect, the string sounding flat (lower pitch.) The diameter of the strings will also effect the placement of frets as a larger diameter string will bend with a larger radius, and a thin string will bend more sharply. The mass of a string (expected to be proportional to the cross sectional area of the string) will effect how much tension is required to achieve a given tone at a given length also. A good player may compensate for a flat tone by pulling (using the friction of the string under their fingers) toward the nut when fretting, or conversely, pushing toward the bridge if the tone is sharp. (Many guitars have some provision to correct this at the bridge but this is uncommon in a classic guitar.) Strings change with wear and readily change in moisture content (changing their mass as a result) over time, adding to this problem of proper fret placement. It is therefore strongly recommended that you not change these dimensions until you have become experienced enough to make subtle corrections for these factors. Accurate, detailed, notes and lengthy testing over the production of several guitars may guide you in making changes in string length and the positioning of frets.
  • fret slotting tool...
  • Cut the fret slots (using a thin rotary blade if possible to be able to end the cut at the edge of the neck.) using the table below as a guide. (on a milling machine it is a simple matter to move the table (and neck) an exact amount from one cut to the next.
  • fret positioning table...
  • Mask the neck so that JUST the fretboard is left exposed, and then apply the aging solution to artificially age the fretboard making it black in color. This process takes many hours and will oxidize the red (iron) of the wood to iron oxide II (which is black, not rust colored.) Use care that the solution does not get on the wood in the wrong spots or it will leave black marks.
  • aging solution...
  • Before proceeding to insert the frets, I like to mask the fingerboard to protect it. Leave a small gap in the masking where the frets will go so that they may be set in flush with the fretboard.
  • Cut each individual fret to its proper length. Keep them in an ordered row as you make them, so that they may be placed in their correct fret slots and not get mixed up. You will need to shape the ends of their tang to precisely fit the ends of the fret slots. They may be hand shaped using files or ground with a small hand held rotary tool grinder. A drop of thin cyanoacrylic glue may be used in the slot to help them stay in, but have a rag with some acetone handy to mop up any excess. If you do use glue, you will need to work rapidly before the glue has had time to polymerize (set.) Do one fret at a time. They may need a bit of force to seat them flush, and they may be either tapped in using a small block of soft metal to prevent hammer marks, or pressed in using a clamp (again being careful to not dent them, or the fretboard, or the back of the neck.) After they are all inserted and the glue has set, then use a small file to radius the ends making sure they have no sharp edges which could cut the player or snag on clothing etc. Do not dress the frets at this time except on the ends as just mentioned.

The Sides and Body

  • Wenge (the wood chosen) is a hard wood with a rough mahogany like texture and composed of light chocolate brown and black alternating in the tight grain pattern. it is: brittle, porous, easily splintered, hard, and has the density of ebony, but it looks good. I laminated together the faces of two boards using Marine Tex (aluminum filled) epoxy to create a single, thick, composite, block from which I later cut the body and sides as a single piece. Take great care in selecting the wood based upon its visual attributes. Orient the grain pattern of the back to best match and flow with the shape of the instrument.
  • Machine this block to make the faces parallel and to the proper thickness.
  • Layout the outer edge outline of the body and the slot for the neck tang by drawing lightly with a sharp white pencil. Leaving a margin around the outside for later error correction (a quarter inch should be plenty if you are accurate about your work,) and cut out the rough shape (with a band saw or coping saw.)
  • This next cut (milling a slot for the neck tang) should be done precisely as possible. Place the block in the milling machine, mill the end of the block where the slot will come out to a right angle to the slot if not already perfectly square, then machine out the slot. You may continue your cuts slightly past their ends to eliminate the two rounded corners which would prevent the neck tang from fitting properly. The dimensions of this slot should allow the neck to fit in perfectly with the fingerboard, aprox. a quarter inch above the body, and with the twelveth fret just at the end of the body (as in a standard acoustic classic guitar.)
  • Before proceeding with the machining of the body, it will be helpful to have the top cut to size. Using the top for a template, you may draw the lines marking the inner cut for the insert of the top and then mark the outer cuts to define the body shape. As these cuts are not done through precise geometric measurements but by eye and hand, this order (slot first, make the top next, use top as template for inner cutout of body) will allow you to make the most even side wall thickness, tapering slightly thicker towards the end of the guitar.
  • Machine the body to allow the top to set in slightly above flush. Machine the outside and radius the outside edges on both front and back (stay away from the slot region and do it by hand later, or wait and do all the radiusing by hand later.)
  • With the help of a friend I held the binding in some steam and bent it to match the shape of the top. A few inches at a time, we glued the first (inner) binding strip all the way around the outside of the top, adjusting with bends with steam only if needed. The strip was glued flush (or slightly above) the top and trimmed squarely at the slot. Using an accelerator with cyanoacrylic glue and you will need little in the way of banding to hold it while it is setting up. Let the glue cure a day and repeat with the next (alternating color) strip of binding untill all five strips are glued flush around the outside of the top.
  • Gently use this a a template to mark the body where it must be further cutout to accommodate the binding now glued around the top. Go ahead and mill or otherwise make this new cut so that the top will again fit into the body. Be as accurate as possible so that the seams will be flawless and not have gaps to be filled.
  • Glue the neck to the body and clamp. Be sure the end of the tang fits snug to the end of the slot and that it is evenly clamped along its length to mate perfectly with the body.
  • Machine the body cavity from the top side to make the neck tang flush with the rest of area previously cut out for the top.
  • You may delay the upcoming gluing processes (except the gluing of the binding around the top) until all the parts are machined (or cut to size.) This is a mater of personal choice, and there may be advantages to either. (The body is easier to machine without the presence of other parts but it may be more difficult to precisely position the bridge and thus the holes needed for the knobs etc.) If your top fits precisely and can be held steady with clearance for borring the holes for the knobs, and you are confident in your precision then you may do as I did, and delay in gluing the top until you have completed the machining of the body (to more easily machine the internal cutouts for the wires from the topside of the body.)
  • Glue the top into the body. Let cure. Machine the top flush and sand to a final finish. (Any builder will tell you to scrape the wood for the superb finish, so bear in mind that you are creating a final surface and treat it accordingly. Go only in the direction of the grain, never against it. Use almost zero pressure and infinite patience for the finest surface.) While this top may have little influence on the actual sound, its appearance will have a great influence on the opinion of guitarists as they expect a perfect finish on the finest of tone woods in any quality handcrafted instrument. I select my spruce with the straightest grain, spaced most evenly, (from an eighth to a quarter inch apart) exhibiting the most and brightest cross grain markings or spidering(?). This page has a photograph of a top of mine as it's background (enlarged and tiled) as an example.
  • Machine the bridge from a block of Cocabolo ensuring yourself that the layers of grain are NOT parallel to the top of the guitar as this would weaken the string tie block structurally. The grain pattern should be at a right angle to the pattern in the top. (See the separate section on the bridge for details on the machining.)
  • This step should not be required if you have a truly flat top and have machined the under side of the bridge flat as well. Check the bridge for a matching fit to the top and precede with the following only if there are gaps or unevenness which need correcting. Sand the bottom of the bridge to match the top of the guitar by placing a sheet of sand paper on the top of the guitar (grit side up!) and using it as a sanding form or block, place the bridge on it and sand with a short strokes in the direction of the neck until it matches the top where it will be placed.
  • If the dimensions are unaltered (or altered properly,) and cut to plan, then the sides of the guitar neck will be very close to being parallel with the adjacent (outer) strings. Our bridge should already have six small holes drilled in it where the wires for the pickup will go through and we will now need some small dowels (round toothpicks seem to work fine for this) which will soon be placed through these holes and into matching holes about to be drilled through the top. using light, easily adjusted, clamps, position the bridge exactly and then using the six holes as pilots drill six holes through the top (drill the outermost holes first, and insert the dowels to help hold the bridge steady as needed.) It may be wise to temporally place the nut, and insert the tuners into the headstock and then string the outer strings to visually check for proper alignment of the string as it runs the parallel to length of the neck.
  • Mask around the bridge as it sets there on the top. This masking should prevent glue from getting on the top where not desired. Wipe the wood with acetone, and using silicone on the dowels and in their holes to prevent the glue from gluing in the alignment dowels, glue the the bridge onto the top, clamp, and wipe off any excess glue (with acetone if using a cyanoacrylic glue. Use caution with the silicone and keep it and any transfered film of it from your fingers or tools away from the wood as it will prevent the finish from sticking also.) Let cure, then remove the dowel pins (redrill the holes if necessary so that the pickup will set in flush.)
  • Using the bridge for alignment (a thin piece of tape may be used to protect the surface of the bridge around the cut-outs for the knobs) bore the holes for the knobs using caution and planning to stop three eights (0.375) of an inch before going all the way through the back. Fostner bits will work best for this and the center of the bit can be ignored in reference to the depth. (The outside of the bit should stop 3/8 of in inch short of going through the back.)

The Top

The Bridge

The Knobs

The Back Cover Plate