Official Blog

Posts tagged “timber

Routing Continued

My stuff finally arrived from Guitar Fetish, what this means is that I can move on with drilling the holes for mounting the bridge and the pickups. The most important part of the instrument is the bridge in relation to the neck. My neck has a scale length of 24.75″. The scale length is the distance between the nut at the top of the neck and the bridge on the body. Tension is created between these two points and it is the vibration of this particular section of the strings that makes the musical notes. Now the distance of the bridge could be any distance from the nut and you could tune the guitar to the open string tunings, say EADGBE. However in order for the notes on the frets to also be the corect pitch (this is known as intonation), the bridge must be placed at the correct distance from the neck nut, 24.75″. The pitch a string makes is a function of the distance of the vibrating portion of the string and the tension of that part of the string. There is a specific mathmatical formular which determines where the frets must go, spaced in decreasing intervals in order to make the correct notes. If the bridge is the wrong distance, each fret will get progressively further away from the correct pitch making the guitar essentially useless unless you are into some form of microtone jazz. So no pressure to get this part right then…

The bridge is attached to make sure it is in the right position.

I attached some of the tuning machines to the neck to string the outer strings to the neck and through the bridge, this way I could line up the bridge with the measured scale length, I also could see where the outer strings would lie. It wouldn’t be much good if one of them was to lie off of the fretboard. After all the testing I marked the spots where drilling was required and attached the bridge with the strings on to test it out. This was the biggest moment so far in the entire build. And find out how I went after these commercials… no just kidding, it worked great, the string action was good and the intonation was as close as you could hope for without fine tuning it later with the adjustable parts of the bridge. Success!

With that sorted it was time to move on to routing the holes for the pickups. The location of these mounting parts aren’t random either. The importance here though is in the overall sound of the guitar, not it’s playability. It’s generally accepted that the best place to place pickups is where there would be a fret divisible by 12, or to put it another way on an octave. This is because the octave represents a point where there are the most harmonics. A vibrating strings doesn’t just create a single frequency but a multitude of related overtones along side the dominant frequency and the octave points have the most overtones. Placing your pickups under these points therefore produces the most harmonically rich sound. Another consideration is the distance to the nut, the closer to the nut the pickup is located the “warmer” or bassier the sound is, further away from the nut the sound becomes “crisper” or treblier.

Neck pickups are nearly always placed under the place where the 24th fret would be, unless there are 24 frets on the fretboard in which case the pickup is placed as close as possible to the 24th fret point. The bridge pickup however is not always placed directly under the 36th fret and may be placed a little closer or further away from the bridge nut depending on your preference for a warmer or crisper sound. I used my other 24.75″ guitars as a reference point for the bridge pickup because I like the sound they produce so I just copied thier positioning. I won’t know what the guitar sounds like through the pickups untill the guitar is finished because wiring up the pickups is the last step before actually stringing up the guitar.

The guitar after pickup routing.

In routing the pickup holes I wasn’t as meticulous as I had to be for the neck pocket, the reason for this is that the holes will be covered by plastic pickup mounts which will cover the hole. It doesn’t need to look great, and functionally I needed a minimum hole size, so I drew an inner and outer line on the guitar and routed between these two lines, the results don’t look amazing but they got the done in a timely manner. What isn’t shown here is the rout for the guitar controlls. My router couldn’t rout deep enough to allow the controls to be threaded trough the body so I routed all the way through. What this means is that I will have to create a front control plate for the controls to thread through which secures them to the top of the body. Something like this… but using a black 3-ply plastic.

An example of the front control plate.

I also made my permenant neck rout fix today and glued it to the neck pocket. I used a piece of the left over pine, cut it to a smaller depth and then used my orbital sander to sculpt it into the shape that I want. I feel much better about a solid piece of wood supporting the neck angle, it will look better too.

Here you can see the results of the neck fix.

The next step in the process is probably the main reason you build your own guitar, the individual look and this is called the finishing process. It involves sanding the bare wood, filling in the pores, applying stain, colour and finally clear coats on top to protect the whole thing. I must say, preparing for this stage has caused me the most stress because sourcing the materials I need hasn’t been easy, but hopefully by sharing my findings it may be less stressful for people reading this who may want to do a build of their own.

 

 


Cutting out the body shape.

So it turns out that I found some free time today and don’t have to wait until Sunday to cut out the body. With the laminating phase over it’s time to sand away all the extras that got stuck to the wood as a reult of the clamping. I used my trusty random orbital sander for this on an 80 grit paper, there was quite a thick layer of glue and thin mdf board that I had to remove so the lower grit was ideal, the higher the grit the finer the sanding, rough and brutal was what I was after here. I only bothered with sanding the top and the bottom because the sides would be cut away, saving on work.

You can see all the extra stuff here that will need to be removed before cutting out the body shape.

The Ash top after sanding off all the residual glue and mdf board.

With all the sanding finished it’s time to cut out the body, I used some black corrugated plastic I had lying arround to make a new template and then traced it round a few times with a pencil. The plastic didn’t cut too smoothly, but the cutting and subsequent sanding of the body will make a smooth shape at the end. To cut the body my Dad used a jig saw, appart from a few tight turns where it left a few burn marks the jig saw did an excellent and pretty smoot job. Of course more sanding will be needed in order to make the sides suitable for painting.

The sanded body blank ready for cutting.

 

My Dad cutting out the body using a Jig saw.

The body came out looking great after cutting, we purposely left the neck section a little wide and a little long. The next steps will be to rout the hole for the neck, once we know the neck fits snuggly the extra wood to the sides and underneath will be cut down to size. Then the routing of the pickups and the bridge can be done followed by the rear rout for all the controls which will be together to avoid extra routing which is a change from the original model.

Something else that I did today was to sand away the finish on the headstock of the neck. Originally you may recall it was finished black with the logo Onxy on the headstock. Luckilly it wasn’t a proper inlay but just a 2D sticker or transfer so the whole thing sanded right off. I plan to make my own watertransfer decal for the headstock which I will talk about in more detail later.

The Fully cut body ready for routing the neck cavity.

 

The headstock after sanding away the previous finish.

An edited image to highlight how the joints between the wood have been stagered for extra stability.

Next post I will talk about the routing process as well as the importance of the neck and the bridge being correctly aligned. I will also discuss the choices for where to rout the pickups as this will have a dramatic effect on your sound.


The Timber Yard

Timber choice is a pretty hotly debated topic amonst guitarists and luthiers with claims about the different tonal properties of different woods. Certainly if you are building an acoustic guitar the wood will make a big difference to the tone and resonance of the sound, as it is the resonance of the wood wich amplifies the vibrations of the strings. Electric guitars are different though, the strings are amplified electronically from signals generated by magnetic pickups. Although many a forum discussion has heated arguments about the different kinds of timbre (i.e characteristics) of the sound different woods make, for instance alder and ash are said to be brighter with mahogany producing a darker sound, the concensus among most luthiers seems to be that it really doesn’t make too much difference at all, excpect for maybe sustain, as the bulk of the sound is generated from the pickups and the amplifier. It is for this reason that in solid body guitar building, the visual characteristic of the wood are the most prized.

So with this and the dimensions in mind I went to a local fine timber yard to see what wood they had in stock. I didn’t want to spend a lot of money with this being my first ever guitar build, so I bought Kauri Pine, which I had planed down from 4cm to 2.5cm depth, and to put on top Victorian Ash which was 2cm thick. Neither are wide enough to cover the entire width of the design so I will have to laminate (glue) two pieces together, I will also have to of course glue the ash onto the pine. Below you can see a picture of the pine before and after cutting.

This is the pine marked out before cutting.
The pine in two pieces after being cut down to size.

Something which I hadn’t considered was where to join the pieces of wood. Being a bit more practical and possesing a considerable amount more common sense than myself, my dad reccomended that I join the top piece of wood with equal size halves and the bottom piece with unequal size halves, or offset if you like.
The reason for this is because of structural integrity. Doing it this way avoids the two vertical joins from my different pieces lining up on top of each other when I glue them horizontally, as in one on top of the other. This way the guitar body will be stronger because it will be less likely to simply snap into two pieces down the middle because the two layers of wood will support each other. The last thing you want is your guitar falling apart!