A Bit about Trimming....

I actually did make back into the shop last week to smooth out my guitar body edges.  This is done using a trim bit in a bench-mounted router.

Trim Bit

A trim bit is a straight bit which has a little bearing on the tip.  The bearing is meant to run against some sort of guide that you want to trim to.  In my case, the material I want to trim is the wood left on the outside of my line after my rough cut through the band saw.  My guide is the the original MDF shape I have been using.

So I hot glue my MDF guide to my guitar body.

Hot Glue on My Figure

I use painter's tape to protect my maple and to make it easier to remove the MDF afterward.  Four little dabs of glue in the corners on the tape and then I quickly place the MDF guide on top matching it up with my pencil line.

Now, I put the trim bit in the router and set the height so that the bit bearing is aligned to the height of the MDF and the cutting edge lines up with the entire thickness of my guitar body.

Setting the Bit Height

You could imagine gluing the MDF to the bottom of the guitar body and using a router bit with a bearing at the bottom.  This kind of bit is called a flush(ing) bit.  There are reasons you might want to do that instead, but using a trim bit is better when you can.

I run the bit around the perimeter of my guitar body.  The bit turns counter-clockwise and so I push the guitar around the bit rotating it counter-clockwise as well.  This ensures that I am moving against the push of the bit which is safer and easier to control and less likely to cause blowout.

Routing Around Carefully

I have to be careful around the horns to go very slowly and to rotate the wood around the bit and not vice-versa so as not to blow out the corners.  A little burning happens because I am hesitant, but I will be able to sand that out later.

After I am done, I can take off my MDF and painter's tape (and dried glue) and I am left with a nice smooth edge.

Smooth Edge

Here it is finished:

Trimmed Guitar Blank

And here it is along with Ed's body he has been throwing together as well:

Body Double

Ed's body is a little further along than mine.

My next step on the body itself is to trim out a little groove to put some edging along the edge of the top.  But, this requires that I have the edging to measure it, which requires spending some money.  Money - I have none, so this will be on hold until I come across some cash.  I could start working on my electronics, but that will also eventually require spending some money.  The neck and headstock...same - money.  Maybe my guitar is on hold for a bit.  We'll see.

Taking Shape...

Wow...two consecutive "work" days at the shop!

Today I rolled some glue onto my maple and marine plywood and threw them both into the vacuum bag.  A couple of 1" headless nails held it all in place until the glue set.

Vacuum Bagging Maple and Plywood

19 inHg this time (We fixed some leaks in the bag.) which converts to 9.33 psi or about 1800 lbs. Two and half hours later, I pulled the (now one) piece of wood out and saw that it was good.  A quick inspection showed me that the pieces were very well laminated to each other.

A Good Connection

If you look carefully, there are no gaps around the perimeter between the maple and the plywood.  Now that it is together, my ruler tells me that my finished thickness is just shy of 1-11/16".

1-43/64" Thickness?

The discrepancy between this thickness and my proposed 1-3/4" has to do with how much I had to plane down the bottom face of the maple to make it sit flat on the plywood.  I shouldn't have had to do that, but the maple pieces came out of the thickness planer not exactly uniform.  Time to check the blade alignment I think.

Now I had to decide exactly where I wanted to cut my body out of this rectangle.  I traced around my MDF guide in pencil where I thought it looked best.

Chosen in Pencil

In this perspective, I was centering the body right and left onto the book-matched joint.  As for up and down, I aimed the bottom line with the point where those two distinct grain lines meet.

Now for cutting.  Off to the band saw to cut just heavy of the line.

Careful to Cut Outside of the Lines

You'd be surprised how nerve-racking it is to hold a heavy piece of wood steady with one hand on a turned-on band saw while taking a picture with the other hand.  These outside curves aren't so bad, but there is a bit of a trick to cutting out the inside curves.

Notching Out Inside Curves on the Band Saw

By cutting away most of the material in a rough triangle, the next step is to cut a series of notches making a series of fingers in the wood.  That way, when the blade passed to cut off each finger, the wood is removable allowing the blade room to "bend" around the curve of the line.  It's really the excess wood that prevents the blade from bending around curves if you don't use this technique.

A careful twenty minutes late, I am left with a rough body shape.

Rough Body

That's as far as I got today.  Tomorrow, I will temporarily hot-glue my MDF guide to the top of my body and use a trim router bit to cut away the excess 1/16" or so around my body.

Clickable Pics...

I noticed that you can click on pictures on the posts dated Nov 3rd and later to get full-sized versions.  Not sure if the system changed over on that date or if I changed the way I put pictures in, but you can now click for bigger pics.  Just a heads up that you don't need to squint so much anymore...

Maple Fit to Laminate...

Upon return to the shop yesterday, I was pleased to see my two pieces of maple had become one and that the joint was as invisible as I was hoping for.  I pulled the masking tape off and it felt solid.  Not bad considering it is only a 1/4" thickness glued together.  Of course, the strength of this particular joint is somewhat irrelevant since what is going to hold the maple together will be the fact that it is laminated onto the marine plywood.

The next step is to plane/sand/scrape the bottom face of the maple so that the bottom face will be flat.  I don't want anything to break when I vacuum bag the maple to the plywood, so I need to make sure the bottom face sits perfectly flat on the plywood.

The last thing I need to do is cut my maple piece to the same size as my plywood piece.  If I don't do this step, when I put the two pieces in the bag, the vacuum will torque the overlapping edge and make for a very bad/impossible lamination.  Trimming the maple to the size of the plywood is a bit tricky.  Keep in mind that the joint between the two pieces of maple marks the centre line of my guitar face.  That is my guide to centering my maple rectangle onto my plywood rectangle.  But, seeing as I shot the inside edges of my maple, there is nothing to say that the outside edges are parallel/perpendicular to the inside edges.

What I have to do is find the center line of my marine plywood and line it up with the center line of the maple (that is, the joint).  Then, I have to decide what section of the maple I want on my guitar face.  Once it is all lined up, I draw a line on my maple exactly parallel to the center line that corresponds to the edge of the marine ply.  With the line drawn, I cut it heavy with the band saw and then clamp a straight edge to the line and take off the excess material with a trim bit on my router.

Now, it's easy because I have a straight, parallel line to my center line.  I can cut the opposite edge easily with the table saw and cut the perpendicular edges with the table saw and a sled.  The sled just lines up with grooves in the table saw to make it possible to make a perfectly perpendicular cut to any straight edge.

Voila...I'm left with a perfect rectangle exactly the size of my marine plywood.  Here is one picture:

Maple Cut to Size

I put my 6" ruler on there to show scale.  Here is another closeup shot:

Closeup of Body Blank

This right side will be the neck side of the body.  How about that quilting, eh?

Last shot to show thickness:

Body Blank Thickness

Two pieces of marine plywood at 3/4" thick and 1/4" of maple equals 1-3/4"...perfect.

Next step is to throw it all in the bag with some glue!

Shooting the Edge...

I guess I lied in my last post about getting back to the shop soon.  It was over a week from then before I made it back in yesterday.  I have been dying to get back to my maple.

The first step was to thickness plane my pieces down to 1/4" thickness.  They started somewhere around a heavy 3/8".  It's crucial when thickness planing figured wood or hardwood that you take off ever so little with each pass.  If you don't, there is a likelihood of blowout in the wood as the blades try to take off too much.  Passing the boards through the thickness planer, we took a light 1/32" off each pass.  Five or six passed later we had removed a full heavy 1/8" off of all four pieces.  Here they are on the table saw:

Figured Maple Milled to 1/4"

The figure came out quite a bit after milling them down since the blade smooths the surface.  Photos, I'm afraid, will never do it justice until the guitar is finished and I take it out of the shop and take a picture with something other than my low resolution iPhone.  Both book-matched pairs came out pretty well - a little blowout on one of the pairs, but it was my backup pair anyway.

A bit about blowout in milling up wood...  When you pass wood over/under/around a blade such as through a jointer, thickness planer, router, etc, you have to take into account the direction of the grain in the wood and the direction the blade is going to contact the piece.  If the blade hits the wood against the grain, it is like petting a bird's feathers from tail to head - all the feathers get messy and ruffled.  If the grain is aligned properly with the blade, the blade helps keep the grain smooth - like petting the feathers in the right direction (Who comes up with an example like petting birds, anyway!?  It's just an image that works for me.  If it works better for you, imagine petting suede against the grain.)  Blowout is easy to avoid with quarter-sawn wood or edge grain pieces of wood.  However, if the wood is full of cathedrals, the grain goes one way half-way through the piece and the opposite direction through the other half.  It becomes difficult since the blade is going against the grain for half the piece no matter what direction you put it to the blade.  So, not only are my maple pieces FULL of funky cathedrals and swirls, but they are also figured.  The figured part is essentially a type of grain running perpendicular to the regular grain.  It becomes impossible to line up the grain with the blade.  You just do the best you can.  That's why you have to take so little material off with every pass to avoid blowing out large pieces as the suede grain feathers ruffle.  It's also important when milling up lumber to avoid mixing metaphors.

Here is another angle of the pair I picked as my favourite.  The figure might be more evident from this angle:

Figured Maple - A Team

Keep in mind that the figure will continue to come out more as the surface gets sanded and finished.  Now that the surface is smoother, the pieces my might be qualified more as quilted than tiger-striped.  That denotation might change after it is sanded.

The next step is to join the inside edges together in an invisible joint (ie. with no gap).  The process is to put the inside seems together as if they are glued book-matched together and then I "close" the "book".  This puts the two joining edges on the same side together.  I just line them up and clamp them down to the bench.  Now I can work on the two edges as if they are one edge which helps to make that invisible joint.  Whatever I do to the edge of the one piece, I necessarily do the mirror image to the other edge.  Exactly what I want...
I used my wonderful (recently sharpened) block plane to clean up the edge.  This whole process is called "shooting the edge."

Shooting the Edge

(You see more of the quilting in this shot...)  Just to be clear, I am planing down the edges of two pieces of maple - one on top of the other.  It might not be obvious from this small of a picture, but I also drew a pencil line with a straight edge about a 1/32" from the edge.  This way, I know how much to plane off before the two pieces have a straight edge.

Now I make it sound easy, but it is not at all.  Shooting the edge involves constantly unclamping and hold the joint together to the light to see if light can get through the gap.  If so, clamp it back down and try to make the joint tighter until no light spills through the joint.  It's a game of patience and accuracy and not settling for anything but the invisible joint.  I clamped and unclamped and shot (shooted?) the edge over and over.  I even had to let Ed take a pass or two while he refined my technique a bit.  I just don't want to underestimate how hard it is to make an invisible joint sometimes.  I have a long way to go.  Practise, practise, practise...

By the end, I was happy with how tight I got the joint.  A little glue and some tape on each side and voila - a glued up invisible joint.

"And the two shall become one..."

Next time I make it in to the shop, I will take the tape off, give the bottom a quick sand, trim my piece to the size of my marine ply rectangle and vacuum bag the two together.  Once that's glued up, I'll use my MDF body shape as a guide to trim route my body shape out of my marine ply and figured maple blank.

Back in action soon...

Hopefully, I'll be back in action soon. I have been pretty busy working on the new website for TenOn Design - the company I work with. Check it out www.tenondesign.com.  I am hoping to get back in the shop this week to mill up the maple and then join it to the marine ply to complete my rough body.

On a separate note...I noticed I took some pictures of my fingerboard which I haven't posted yet.

Ebony Fingerboard with Inlay Holes

Here is my actual fingerboard.  As I mentioned previously, it is already made and slotted for frets.  Notice that there is quite a bit of fingerboard toward the bottom that doesn't have fret slots.  Nathan suggested - and I am very tempted to - cutting a few more slots to extend my frets to a higher range on the guitar.  I believe this fingerboard has 22 fret slots and I may take it up to 24.  It will be a good way of learning how hard it can be to cut accurate slots.

The inlay holes are already cut out too for the pearloid inlays I will be putting in.  The inlays came with the fingerboard as part of the gift.  I had to spend quite a bit of time last week scraping off tape glue from the fingerboard since someone *cough* duck taped the inlays to the fingerboard for transport.  Using painter's tape or something would have been better.  I not only had to scrape the tape glue off of the fingerboard, but also off the inlays themselves.  Here are the cleaned up inlays sitting loosely on the fingerboard:

Pearloid Inlays on Fingerboard

They are gorgeous, I think.  I am also going to extend the pearloid theme to more of my guitar.  Pearloid is a plastic-like material that is meant to imitate mother-of-pearl.  More on pearloid in a later post.

I am excited about getting back into this.  Stay posted!

Big purchase...

I bit the bullet today and went to try to purchase my guitar top material.  I headed over to my local fine wood supply today with Ed.  We had a lead on some figured maple there that we have been putting off looking at for a few weeks.

We got there and saw that the supply was still available.  It was at the top of a stack of other material and it wouldn't have been possible to look at it without pulling it down with a forklift.  Our contact there said that he had pictures of all the boards online and we proceeded to go look at them on his laptop.  To our dismay, none of the boards were really what I was looking for.  All the stock was western maple and we were expecting eastern maple.  Western maple is more yellow/brown compared to a white/beige eastern maple.  For that reason, eastern maple is better suited to my final design.  Also, the western maple stock at the wood supply had a lot of heart wood in the boards which works well for some applications, but not guitar tops - it just ends up looking like a stain to me.

To make matters worse, the wood supplier had already sawn planks into book-matched pairs (resawn in two and then one piece is flipped horizontally to make a mirror image of the other piece down the middle).  This fact wouldn't have been so bad (especially since I want to book-match my guitar top), except that now the supplier didn't want to split up the pairs, nor cross-cut the planks.  Seeing as each plank was over ten feet long and I was being forced to buy two, it was going to cost about $250!  That's actually a really decent price, except that I only would have needed 18" of each plank.  That would leave upwards of 17' that I didn't need for this project.  Too rich for my blood - especially since it was the wrong look for my project.

We were just about to leave when our contact asked how big a piece we were looking for.  I said two book-matched pieces about 1/4" thick, 6-1/2" wide and 18" long.  He said, "follow me," and then proceeded to take us to a corner of the warehouse where he had four book-matched (two pairs), figured, eastern maple that were each about 3/8" x 8" x 24".  Imagine that!  Perfect size.  Beautiful figure!  I, personally, only needed one book-matched pair, but our contact was willing to part with the second pair at 50% off.  Since we plan on many a guitar project (in fact, Ed is also building one concurrently), we took the bundle for a really good price.  Here are the two pairs on the table saw:

Book-Matched Eastern Maple

The photo really doesn't do the pieces justice.  For one, the two pairs (especially on the right) have burning from the rough milling.  Ironically, though, the burning gives a bit of an idea of the figure since the figures in the wood have different densities so they burn at different temperatures. It's hard to describe the figure, but it is quite stunning.  There is some very prominent tiger-striping, but also evidence of quilting.  Furthermore, the grain cathedrals all over the place producing some beautiful shapes.  Here is a close up of my favourite pair (I made the picture larger than usual for your viewing pleasure.):

Body Shape Drawn on Figured Maple

We scraped away some of the burnt wood.  You can sort of see the crazy grain and how it will book-match down the middle of the body.  You can also see some of the tiger-striping and quilting.  Keep in mind that this is somewhat rough lumber as it has only been resawn to thickness.  It has not gone through a thickness planer, nor has it seen a sander or been coated in glossy finish.  The grain and figure will really come out then...can't wait!

Next steps - I need to thickness plane the two pieces to my final thickness (a heavy 1/4") and then joint the middle edges of the two pieces so that they can glue together with a perfect seem without any gap.

Administration...

A bit of an administration post today...

I changed my settings so that you can now post a comment without creating an account.  Just select "anonymous" from the drop-down box.  Of course, you can still sign up for an account or just simply sign your name at the bottom of the comment if you want.  I figure it is a pain to have to go through an account creation process sometimes just to type in a quick comment or question.  Hopefully, this change persuades more of you to comment more regularly.  And about comments...I have access to some smart people, so if you have woodworking questions I can ask Ed, or guitar questions, I can ask Nathan...I'm just saying even if my posts come across as "simple" or "uneducated" I have access to some good peeps.  As my Indo-Canadian friend, Raj used to say, "Don't shy!" (Make sure to say it with the retroflexes rather than alveolars...)

Also, if you want to follow my blog, but are tired of pressing F5 all the time in your browser, please sign up for my email alerts on the top right where it says "Want email alerts of my new posts?"  It's a quick process and will send you an email alert only when I write a new post.  There is no spam and I promise I won't email you anything else.  It is also quick and easy to unsubscribe, so no excuses...

Lastly, please feel free to advertise my blog around.  Make a quick Facebook comment on your wall or whatever.  It would be great to get a number of people reading about my ideas.  I already have some views from Canada, USA, Australia, Ireland, Malaysia, and Switzerland.  Megalomania is my middle name...Muhaha!  Muhaha!  The power, oh the power!

Muhaha!  Muhaha!

Headstock...

The headstock is the part of the guitar at the end of the neck on the opposite end as the body.  All six tuning machines are there and it is the anchor for one end of the strings.  Nathan tells me that the headstock is normally made out of the same piece of wood as the neck, but that it is known as a weak point in the guitar.  Maybe I will consider making it a separate piece and joining it somehow (glue, bolts, etc).  This could make it considerably stronger, but goes a bit away from the typical formation of a guitar.  I have to do some research and think about this a little bit more.

Here is a picture of a guitar headstock:

Gibson Les Paul Headstock - 3L/3R Tuning Machines

This is one of my favourite shapes.  I like the 3 tuning machines on one side and 3 on the other.  This is known as 3L/3R.  3L/3R is opposed to 6-in-line  which can be seen on a lot of Fender style headstocks (or some other configuration).

Fender Jaguar Headstock - 6-in-line Tuning Machines

I seem to like 3L/3R over 6-in-line, but maybe I will get creative with my headstock and do 1L/5R or something wacky.  Here are some other headstock styles.  Anyone have a preference?

Gibson Les Paul Headstock

Fender Headstock

ESP Headstock

Rickenbacker Headstock

The Dean Edge Bass Headstock

I kind of like this last one even though it is a bass guitar.  Just brainstorming...

Sticking my neck out...

I have decided also to make my neck out of maple to match my body somewhat.  That is to say, the body of the neck will be maple; the fretboard will be ebony.  I forgot to mention that part of Eunice's gift to me (via Nathan) was an ebony fretboard.  It is pre-slotted for frets, but I admit I don't remember how many frets it has.  I do know that it is a Gibson scale length.  Can someone tell me if Gibson used 24.75" or 24.65" scale length?  Is there a relationship between scale length and the number of frets?  Seems to me there should be.  (For those who don't know, the scale length is approximately the distance the strings vibrate.)  Also, is the headstock (the part with the tuning machines) connected to the neck or is it part of the same piece as the neck? One or two pieces of wood?

Ebony Fretboard with One Fret

The picture above shows the slots in the fretboard as well as what the fret wire looks like when it is in the slots.  I guess you could consider it cheating to use a pre-made fretboard (aka fingerboard).  The thing is, there is some math and/or patterning, as well as some very specific tools which I don't have at the shop needed to get the slots exactly in the right place.  If they are wrong, the guitar will never be in tune and then there is really no point.

So, right from the bat, I will tell you beforehand which parts of the guitar will be pre-fabricated.  I will not be making any of the pickups from scratch or switches or electronics.  I will be putting them in a special order which will require some soldering on my part (and already some from Nathan), but I will not be coiling my own wire around magnets.  I will not be making the fingerboard, nor the fret wire.  I will not be doing any metal-working at all.  So, no tuning machines or truss rod or plates or knobs.  All that stuff can be bought and I will not feel cheated by not making them from scratch.  Keep in mind, this is my first axe, so I can always do all these extras on a future project.

Anyway, I will have to vacuum bag the fingerboard to a maple neck at some point, so that leaves another piece of maple to buy.  The neck will be a set-in neck, not a bolt on or a through neck.  This just means that the neck doesn't just attach by means of some bolts (bolt on), nor does it pass all the way through the body as part of the body (through neck).  I was originally going to do a through neck, but I decided that it was more important for me to rear-mount all my hardware.  More on that some other post.

Just another pickup line...

I haven't had a chance to go figured maple shopping yet, though I have a really good lead on a stash somewhere here in town by our shop.

I wanted to add just a little to my discussion on my choice of pickups and how they will be configured in my guitar.  Remember that I am going to put in two Seymour Duncan P-Rail Humbuckers.  Also, remember that each humbucker has six possible configurations of single coil or in and out of phase double coils.  Well, that is not quite true.  Each pickup really has seven configurations.  In addition to the six configurations I have already talked about, there is also the possibility that both coils can be off.  In other words, the entire P-Rail could be off.  I can either turn off the entire Neck pickup, or I can turn off the entire Bridge pickup or I can have both pickups on. (Both pickups off too, which just means that the guitar is completely off.)  So, there are three combinations of pickup selection.  1- Neck on, Bridge on.  2- Neck on, Bridge off.  3- Neck off, Bridge on.  (4- Neck off, Bridge off.).  For a two pickup guitar like mine, this is normally configured with a three-way switch.

3-way Switch

With a three pickup guitar like an H-H-H, or S-S-S, or S-H-S, etc, a five-way switch is often used for all the pickups - 1- Neck on, Middle on, Bridge on.  2- Neck on, Middle on, Bridge off.  3-Neck on, Middle off, Bridge off.  4-Neck off, Middle on, Bridge on.  5-Neck off, Middle on, Bridge off.  Or something like that...
Anyway, with my two pickups, I have only three combinations.

But yes, you guessed it; I want my two pickups to be even more configurable.  What if I want my Neck pickup to be only 50% on and my Bridge pickup to be 100% on?  Well, I am going to use a pan/balance knob just like the one on your stereo that chooses between the left and right speaker (A "stereo" is an ancient device like an mp3 player or mp3 file equipped smart phone, but only bigger and it doesn't play mp3s.).  It's called a blend potentiometer or blend pot.  This is the one I'm going to buy:

Blend Pot - $5.35, Ultimate Configurability - Priceless!

This one is somewhat special in that it lets me go from 100% Neck, 0% Bridge to 0% Neck, 100% Bridge with both pickups at 100% when it is centred (not 50% each).  This is important to me since pickups don't sound the same when they are not at full volume and I didn't want my only option of using both pickups to entail only having them at half volume.

Any questions...?

Figuring out the face...

I made it back to the shop today.  The glued up marine plywood is super solid.  There are no gaps or bubbles as far as I can tell.  It is essentially one piece of plywood that is 1-1/2" thick.  Here is a picture.  I put the pattern on top to show the scale.

Pattern on Body Block

The next step with the body is to find my face material.  The finished guitar body will be about 1-3/4" thick at its thickest.  I already have 1-1/2" of material with the marine plywood, so I am missing about 1/4" of material that I will use for my face/front.  This material could just be more plywood or some other non-pretty thing if I wanted to paint the whole guitar in an opaque colour.  In other words, if I am covering the whole guitar in solid finish, I don't need to worry about the prettiness of my body, just the weight and density and structure, etc.  But, I want a stained wood front and a solid opaque back.  The solid back is why I am alright with using plywood for the back.  I can't do the same with the front.  Stained plywood looks like plywood.  I want something better.  And so I am thinking of using maple for the front.  This is a classic choice.  Not just any maple, though; I am going to use figured maple.  Figured maple looks like this:

Tiger Striped Maple

This is a type of figure called tiger striped, curly, or quarter sawn (There are subtle differences between these three categories, but I don't know what they are...maybe just a naming preference).  There are other types of figuring too like quilting:

Quilted Maple

And birdseye:

Birdseye Maple

There are other types of figuring too, I'm sure.  Scientists really have no idea how figuring happens or why.  Loggers simply fell trees and a small percentage are figured.  They can be slightly figured or highly figured.  Sometimes they are assigned a percentage of figuring like 80% Birdseye or something like that.  Because figuring is random among trees, it ups the value of the wood.  It is quite beautiful, so I think it is worth the extra buck.  Personally, I like the tiger stripping for my guitar face, but I will entertain comments trying to convince me of another look.

I need to buy a piece of figured maple and mill it down to 1/4".  There is no piece kicking around the shop unfortunately (that would be very unlikely!).  Once I have it, I will cut it down to a rectangle the same size as my marine ply.  Then I will vacuum bag the plywood and maple together.  Only then will I be able to use the pattern to cut out my guitar body.

Pickups...

I didn't make it back to the shop today.  My little one kept me up most of the night.  Saws and sleep deprivation rarely mix well. I'll have to wait until tomorrow to see how well my marine ply glued up.

Of course, an electric guitar requires not only a body, but also some electronics.  Today, a bit about my choice in pickups...  A pickup is, very simply, a magnet surrounded by a coil of wire that picks up string vibrations and converts them into electricity.  That electricity travels down the cables and eventually comes out of some sort of speaker which converts the electricity back into vibrations (aka sound).

There are two main types of pickups - single coil and humbucker.  Single coil pickups are just that - one coil of wire - essentially one pickup.  Single coil pickups were the first type of pickups and they are used to produce everything from Hawaiian steel to lap steel to jazz guitar sounds.

Single Coil Pickup

The main issue with single coil pickups is that the coil of wire also acts as an antenna and picks up all sorts of radio frequencies and hum.  They are quite noisy in that sense.  So, someone from the Gibson company came along and had the bright idea of taking two single coil pickups and putting them side-by-side at opposite polarity (remember that they consist of a magnet, so north with south, north with south).  This serves to cancel out the radio noise and hum.  The double pickups are called humbuckers because they "buck" the hum.  All they are is two single coil pickups in a 69 position.  Humbuckers are used in most modern rock and heavy metal because of the warmer, fatter sound.

Humbucker

I like the idea of no noise in my pickups.  I also like the idea of being a rock guitar god.  So, for my custom guitar, I'm going to use humbuckers.  However, since I am also trying to make a diverse guitar that can pretend to be a number of different types of guitars, I also want to be able to have that single coil pickup sound available.  Maybe someday I will join a country western band.  Fortunately, there is a way to have both.  If wired correctly to a switch, a humbucker can be made only to play one of its two coils.  In other words, by turning one of the two coils in a humbucker off, you are left with a single coil pickup.  Even better, Seymour Duncan, makes a specialized humbucker called a P-Rail which is a humbucker that consists of two famous types of single coil pickups.  One single coil pickup is the P90 which is a favourite among many guitarist.  Gibson used it for many years.  The other single coil is a rail style coil made famous by the Fender Stratocasters of the '50s.  Together, the two coils form a decent humbucker.  If wired correctly, using the P-Rails will give me a guitar with a very diverse sound.  I guess not only my body shape borrows from both Gibson and Fender.

Seymour Duncan P-Rail

So that's a bit about pickups.  But of course it doesn't end there.  I still need to decide on how many P-Rails I want to put on my guitar.  Yes, that's right, most guitars have more than one pickup.  A standard notation for humbuckers is H and for single coil pickups, S.  Thus, a guitar with three humbuckers would be labeled H-H-H.  That's a bit overkill for me.  Some Ibanez guitars have that configuration.  Stratocasters have an S-S-S configuration.  I'm going to go, instead, with two P-Rails - so H-H.  Remember too that if I wire the P-Rails correctly, I can fake a pretty decent S-S, S-H, or H-S by turning off the appropriate coils.  I can also mix and match between Rails and P90s.  In fact, it gets even more complicated.  Each P-Rail humbucker pickup has six combinations.  In addition to the single Rail and the single P90, the combination of the two single coils (that is, the humbucker) can be configured in four ways.  The humbuckers can be wired in series - one coil after the other, in parallel - both coils beside each other, in series and out of phase, and lastly, in parallel and out of phase.  If you picture sound waves pushing and pulling the air around you, "out of phase" just means that one coil is pushing air while the other coil is pulling air.  The effect is that most of the sound is cancelled out by the coils working against each other and the sound that remains is very nasal and ethereal.  The six combinations for each P-Rail then:

1. P90
2. Rail
3. Humbucker in series
4. Humbucker in parallel
5. Humbucker in series and out of phase
6. Humbucker in parallel and out of phase

Considering I have two P-Rails (a bridge pickup and a neck pickup), with 6 combinations each, that gives me 36 possible configurations (I won't stop there, but more on that some other post).  I hope you are starting to understand what I am meaning by a diverse guitar.

It just so happens that Nathan had a couple of like-new P-Rails kicking around in his hoarder's collection of guitar guts.  He gave Eunice an incredible price for them and they are part of what I got for Eunice's birthday last week.  Nathan also just so happened to have wired each one to a 6-way switch.  I'll show a picture or diagram of that some other time.

Vacuum Bagging...

I've decided to build the core of my guitar body out of marine plywood.  By using plywood instead of a solid piece of maple or something, my guitar will be slightly lighter.  Also, there was half a sheet kicking around the shop so that makes my project slightly less expensive.  (If it's already purchased, it's free, right?)  Marine ply has been used for guitars before, so I am not breaking any new ground, plus the finish I have in mind for the guitar doesn't warrant a solid piece of expensive hardwood.  Lastly, marine ply is very uniform/flat with no bubbles in between the layers and is treated to be resistant to rotting due to moisture.  It is very high quality - good enough to be used on boats and docks - thus the name.

Friday, I cut a couple of rectangles out of marine ply just slightly larger than my body pattern.  I need two rectangles since this plywood is 3/4" thick and a regular guitar body is much thicker than that.  Today, I had to glue the two pieces of 3/4" plywood together to make one piece at 1-1/2" thick.  I used a technique called vacuum bagging.  Essentially, you put glue on the two pieces, put them inside of a sealed plastic bag and suck all the air out of the bag.  No air in the bag means no air between the two pieces you are gluing, which means they suck together and glue up really nicely.  We use this technique to install decking on yachts as well as to laminate veneers to desk tops and such.  It's a bit of a black art, but works amazingly well once everything is figured out.

Homemade Vacuum Pump

First, I rolled a little bit of wood glue onto both pieces of plywood.

Rolling Glue

Then, I place the two pieces together and put everything in my sealed bag and turn on the pump.

Sucking all the air out...

The towel helps circulate the air as well as protect the plastic bag from the sharp corners of the plywood.  Keep in mind that you cannot use a regular household vacuum to do this technique; there is not enough suction.  We built our vacuum pump using an old pump we bought off of some stranger and some hosing.  A regular household vacuum will pull about 1 or 2 inches of mercury (inches of mercury = inHG.  30 inHg is a perfect vacuum with NO air left).  I have seen our vacuum pump pull as high as 21 inHg.  It usually doesn't pull that high due to small leaks in the bag or where the hose goes through the bag.  In this case, I got just over 17 inHg.

17 inches of mercury (inHg)

A quick calculation tells me that 17 inHg equals about 8.35 pounds per square inch.  That means that for my two pieces of plywood, I have the equivalent of a weight of about 1600lbs sitting on top of them to glue them together.  It would be difficult to clamp it that tight, not to mention that evenly.  The greatest thing about vacuum bagging is that the pressure is completely even.  There are no loose spots.  I turned the pump off after a couple of hours and tomorrow we will see if everything glued up alright.

General Body Shape...

On Friday, towards the end of my day, my friend Ed and I made up a general shape for my guitar body.  Ed is a ticketed journeyman/master in fine woodworking with a background in high-end yacht joinery.  He and I have been friends for about 15 years and I have worked with him for the last two years learning a trade in custom furniture building.  Check out our website at www.tenondesign.ca.  Ed and I (and my brother-in-law, Nathan) will be building my axe.  Of course this means that I have access to a full wood shop for my guitar project, not to mention a real woodworker...

So on Friday, Ed and I made up a pattern for my guitar body.  Seeing as my guitar is custom, I didn't want to just trace an existing shape, nor did I want to get entirely crazy with a rediculous, artsy shape, so my shape ended up being a cross between a Gibson SG and Fender Statocaster.

Gibson SG

Fender Stratocaster

The purists among you (cough, Nathan, cough) will baulk at my "original" shape saying something like, "that just looks like a botched SG and Strat abomination!"  Well, my defence is two-fold. Firstly, the purists among you (hopefully with the exception of Nathan) have already abandoned my blog when I mentioned amp modeling - preferring, or course, real guitars and real amps and real money.  So I probably don't need to worry about you.  My second argument is that if I want an SG or a Strat, I'll go buy one.  I am simply taking my favourite parts of two pre-existing designs and combining them into something I can nearly call my own.

I like the double cut-away of both designs, but prefer the very slightly asymmetric top and bottom cut-away of the SG over the extreme unbalance of the Strat.  However, I don't love the pointy devil horns of the SG and prefer the rounder feel of the Strat cut-aways.  So without further ado, here is my design:

Custom Guitar Shape

Ed helped me trace the shape onto a piece of 1/4" MDF, erasing and redrawing until I was happy with the look of it.  Following that, I cut it out very roughly with a jigsaw, then quite accurately with a band saw.  Lastly, I sanded it all smooth with a spindle sander in a drill press and a block sander by hand.  Despite it being the first construction day on the project, I already goofed and over-sanded the part towards where the neck will attach.  I had to superglue some extra bits of MDF to where I had over-sanded to build out the material again to the full shape.  The first of many, many goofs, I'm afraid...