Electric Guitars

This lovely all-black (murdered) Mexican Strat is another one of Dr. Shoen’s axes.

 

This guitar had languished in the trunk of a car and had acquired an interesting twist in the neck.  A very fine white dust permeated every internal cavity of the guitar.  The tremolo was functional but for some reason, releasing the tremolo did not necessarily return the tuning of the open strings to where one would expect it to be.  A few of the bridge adjustment set screws were corroded beyond usefulness.

 

A conventional setup was just not adequate to return this guitar to playability.  More work was needed.  This is something that happens from time to time… a situation that every guitar tech dreads. However, I run where angels fear to tread!

 

Let’s press onward to disassemble this guitar, do a little exploratory surgery, and take some guitar tech porn pictures along the way!

 

 

 

Here’s all the info you need to make illegal copies of this guitar, complete with a valid serial number.

These are Dr. Shoen’s preferred string set.  When I asked him why he puts these strings, he said that they are the cheapest.  Excuse me while I scratch my head.

Can you see the fine white dust in the left end of the tremolo spring cavity?  Another OCD peeve of mine is tremolo springs installed this way.  Somehow it makes sense to some people, but the center spring will go slack before the outside springs.  For a constant spring rate, the springs need to be parallel.

Off they come.  I feel better already!

Guitar Tech Porn.  Nice locking tuners on the headstock of this Strat.

Off comes the neck.  No shims?  The geometry of this guitar will change as we rework the neck twist and retrofit the bridge with new set screws, so I’ll go with this configuration and add shims later if we need it.

These screws are really loose, almost falling-out loose, particularly on the treble side.  Perhaps this has something to do with the tremolo not returning to an in-tune condition.

This fretboard was cleaned and oiled in the first setup.  The guitar had not been played much since then.  I suspect that the oil has floated out some more grime from the pores of the rosewood.

Some grime was softened around the nut, so I will apply this super-secret cleaning tool to the nut.

Guitar Tech Porn.  Lockers are unlocked, string holes are lined up, and there is a slight reflection of the nut in the surface of the rosewood fret board.  Nice, wouldn’t you say?

I began to disassemble the bridge and prepare to install new set screws.

The new set screws are wrapped in Teflon tape, then threaded in from the bottom, where the Teflon will gently lock the screw in place while permitting adjustments in the future.

The bridge is ready to return to service.  Those tiny scratches are from the ends of the old set screws.

Guitar Tech Porn.  This is a side view from the low E string side, showing everything going back together.

Guitar Tech Porn.  Another view of the new set screws.

The bridge has been reassembled.  Before the strings are installed, I’ll tighten the intonation screws so that the saddles slide forward onto the open string as the intonation is set.  I’ve discovered that if I start with the intonation screws fully extended, as they are here, tightening the screws results in string deformation as it rides over the saddle, and takes forever for the string to settle back into a ‘straight line.’  While the string is straightening out, there is no point in doing any further adjustments.  Waste of time.  So now I ‘subtract’ unsupported string length by moving the saddle forward to set intonation.  The vibrating portion of the string is always ‘clean.’  Or I’m just OCD.  Again.The neck goes back on without a shim, so we can see where we are with the other adjustments.

Guitar Tech Porn.  Slip the strings into the locks and tighten them down.  Love it!

The saddle should ride flat on the guitar body.  It takes a while to get the screw heads in just the right place for this saddle to stay put.  I’m a little worried that it won’t stay put when the string tension takes over.  We shall see!

This is the way an OCD Guitar Tech installs tremolo springs.  It is also OK to put the two springs on the outside and have one in the middle.  For now, this will work OK.  I’m also thinking that those screws holding the bridge in place aren’t going to stay put, so this just seemed like the safest thing to do.

Jen works the Strat into a lather.  Sure enough, the tremolo is acting up again and the low E string is buzzing.  Again.

The tuning pedal shows that the tuning continues to change as she plays the guitar.  Not good!

Time to pull out the big guns.  Callaham Guitars has a premium tremolo assembly for Mexican Strats.  There are a couple of key differences that will help this guitar out, as we will see below.  The strings and neck come off the guitar again at this point.

A thing of beauty, the Callaham bridge is visually very close to the original Fender part, except for the CG stamp on the saddles.  Referring to the earlier picture of the intonation screws, here I’ve got the saddles pulled all the way to the back so that the springs are compressed.  As intonation is set, the vibrating portion of the string will get shorter.

Here’s the real difference.  On the left is the original Fender bridge, and on the right is the Callaham bridge.  Note that the bevel does not extend all the way underneath the screws.  This should allow the screws to be tensioned adequately to hold the bridge plate down, yet allow the tremolo to pivot the whole assembly on a single axis.  In other words, the axis of rotation of the bridge assembly is held in a more stable point, right at the ridge of the steel, right underneath the screws.  In the Fender system, we lose control of the geometry of the bridge once the bridge plate tilts, as there is no groove or knife edge anywhere on the screws to act as a specific pivot point.

Another big issue with bridge stability is that the screw holes on the treble-side strings are stripped.  The wood used to make this guitar body is a little softer than I expected, maybe alder.  (You Strat-heads can message me with your inputs on this subject.)  My plan is to cut plugs from rock maple, drill these six holes to fit the hardwood plugs, then re-drill the hardwood plugs to fit the Callaham bridge.  I’m not a big Tone Freak but I have a feeling that the “Q” or the mechanical resonance of the body will be a little higher with the bridge screws held in place with rock maple.  Maybe Les Paul was on to something when he laminated maple over mahogany.

The plugs were cut using the 3/16th plug cutter from Stewart-McDonald.  This 3/16th inch plug cutter makes the smallest practical sized plug available, to my knowledge.  The smallest plug cutter I could find otherwise made a plug that was 6mm in diameter.  Here is one of the rock maple plugs getting a coat of hot hide glue.  The plugs are a little longer than the holes in the body, so I have something to hold on to!

The inside of each hole gets a coat of hot hide glue, too.  It takes about a minute to get each plug into the body of the guitar, at which point the hide glue begins to harden.

Each plug is carefully trimmed flush with the original body contour.  This takes a while.

The new Callaham bridge is positioned at the point where the intonation adjustment will do the most good, then is held in place with some No-Mar tape.  A brad-pointed drill bit is used to mark the center of each screw hole.

This body is just wide enough to prevent me from using the drill press.  Everything is taped off so I can use the hand-held Port-A-Lign to drill the screw holes accurately.

The Port-A-Lign is doing its magic.  The rock maple plugs go all the way through the body, but the screw hole depth is limited to the exact screw length by controlling the length of drill bit extending beyond the jaws of the Jacobs chuck.  This allows the longest possible contact between the screw and the rock maple, all the way to the tip of the screw.  A tiny bit of tape covers the ends of the chuck jaws, in case I hit the rock maple with the Jacobs chuck.

Guitar Tech porn.  The Callaham bridge kit even contained new screws.

The Callaham tremolo spring claw was not tinned to accept a ground wire.  No problem.  I have a big soldering iron.  The claw rests on a piece of ceramic tile because it gets WAY too hot to sit anywhere else while I’m doing this.

The new Callaham tremolo arm is at the top, and the original Fender arm is on the bottom.  Dr. Shoen prefers the longer arm.  They are mechanically interchangeable, in any case.

I got ‘medieval’ with the neck to get the twist out of it.  No pictures, because it wasn’t pretty, and both my hands were busy.

After the strings were re-installed and the setup begun, I really didn’t need any shims in the neck.  String buzzing was gone.  The new bridge made it easy to radius the strings and set string height.  Intonation was dead-on for where I placed the new bridge, with little adjustment necessary.  Four tremolo springs were installed to get the tremolo working perfectly. I picked up this guitar to play it and didn’t put it down for forty-five minutes.  It was alive in my arms.  And I hadn’t plugged it into an amplifier yet.  The sustain of each string was fantastic.

Dr. Shoen played it acoustically, with a lost look on his face.  I was afraid something wasn’t right.

When he looked up, he said that he was ‘inspired’ by playing this guitar.  He felt that I took a $500 guitar and turned it into a $1000 guitar.  Jacked into my Gibson amp, this thing just sang.

Now go out and get that guitar out of the trunk of your car,

 

Thanks for reading all the way to the bottom!

CONTACT INFORMATION – David Latchaw  281-636-8626

 

Jennifer found this stunning Epiphone Les Paul at a local music store.  They didn’t know what they had!  Let’s clean it up.

The only issues I can see are that the pick guard is white but the other parts are ivory.  The nut is probably polycarbonate.  All the other hardware and pieces appear to be pretty good stuff!  Off come the strings.
One of my pet peeves is long, dangly string ends.  Why can’t people watch a few YouTube videos and make their guitars a little less dangerous?
The tail piece is branded Epiphone and is steel.The bridge is steel as well, also branded Epiphone.  String saddles are steel.  Everything here is in good shape.Jen wanted to remove the pick guard.  It didn’t match, and she likes the Studio ethos of a Les Paul sans pick guard.I have been told that this is called a pickguardodectomy.  From this view, you can see the mismatch of colors.My guess is, this guitar has never been polished since it left the factory. The finish is otherwise in great shape!The knobs were not cracked and were not stuck on the pot shafts. The nuts were tight.The neck pickup had been screwed way down, but was functional at the music store.  Here, I’m temporarily removing it so we can clean up everything.The saddle studs were very loose in their holes, so I bushed up both of them with half-inch Teflon tape.I checked the electronics.  Everything was functional at the music store. I removed the covers to remove gunk and better polish the finish.  This switch is 100%.The jack is like-new. Again, I removed the cover to better polish the finish. Note the more-than-adequate service loop. I wish more guitar companies did this, but, alas, copper wire costs money. Thus, you can always be assured that you won’t get any more than necessary. But this Epiphone is a welcome change from the norm.The bushings on the top side of the tuners were not even finger tight. I’ll take this opportunity to pull off the hardware and polish the headstock.The entire neck is finished. Here are some cryptic marks on masking tape for you to decipher.True to the Les Paul formula, this body appears to be mahogany with a maple top.After I installed the neck, I noticed that the badge on the headstock appears to be an inlay, perhaps synthetic abalone.The front of the body is done and is ready for strings. The neck got the usual fret polish and cleaning. The fret board was filthy, taking three applications of Dr. Duck’s to bring it back to life.The back is absolutely perfect, no buckle rash or any signs of chips or damage.Strung, tuned, truss-rodded, string-heighted, intonated, played.  Jen found a real winner here!Welcome to the Les Paul Zone!

This slick Japanese-built Fender Jazzmaster is a fine representative of Fender’s offset-waist solid body designs.

The volume potentiometer for the bridge pickup was open-circuit over part of its range.  The set screws under the bridge were coming loose and the string height would get crazy-low over time.  This guitar also broke high E strings for no apparent reason.  Let’s go to work!

The control on the right, the volume control, has been replaced before.  This is an inexpensive potentiometer, often sold under different hobbyist brand names.  We will continue to disassemble the guitar to look at a couple of other issues.

Years of sweat have gifted us with a bit of rust and staining of the beautiful white finish.  Fortunately, most of this is out of sight!

But I do want to clean up what I can, if for no other reason than to get everything back flat again.  This abrasive stick is making a tiny dent in the rust.

The heavy artillery is brought to bear to get off the really hard-to-clean stuff.  Wish me luck!

The various bits of hardware were polished and waxed.  This is pretty solid now.  Nothing seemed out of the ordinary that would account for strings breaking.  Maybe the problem will show up during setup.

The neck angle is good on this guitar.  But, off the neck comes, if for no other reason than to clean up this hardware and to focus on the fretboard and fret cleanup away from the pickups.

The frets are getting a quick dressing and polish.  The fingerboard was dry and soaked up several applications of Dr. Duck’s Axe Wax.  I love that stuff!

This is exactly the shim used by the last person who put this guitar back together.  I matched this shim thickness with a leaf of steel from an inexpensive set of feeler gauges from the car parts store.  Also, can you spot the ‘country of origin’ decal on this guitar?

All the hardware on the lower half of the pick-guard was unbolted, and the pick guard was set to the other side.  The neck pickup controls on a Jazzmaster are small potentiometers set up on a roller-like knob scheme.  Those are 100% and were returned to service as-is.

The new control is an Allen-Bradley sealed military control.  As a rule, service people prefer unsealed controls, because they can be cleaned and lubricated.  However, in this case, I decided to go with a sealed, stainless-steel unit, because of the sweat and grime that this guitar has seen over time.

As the body of the Allen-Bradley control is stainless steel, it is nearly impossible to get a good solder joint using conventional solder and heat sources used for common electronics.  In this instance, an extra toothed lock washer and a ring lug will make the positive connection between the metal body of the control and the ground buss of the guitar.

Here, I’m magnetically coupling the output signal from an audio signal generator to the bridge pickup to check the proper operation of the new volume control.  The output from the guitar is jacked straight into my new Marshall Stack visible in the background.  Yep, we’re in the Big Time here!

While I’m at it, I am verifying the proper operation of the neck pickup and tone control.  Look ma, no strings!  It’s kinda nice to be able to check out the electronics without having to install all the pick guard screws and a set of strings.

Here is the new Mustang bridge. I will put a coating of Teflon tape on the set screws, which should form a mechanical barrier to keep them from vibrating loose, while not locking the screws down hard as would be the case if I were to use Loc-Tite or nail polish.

This is my trusty roll of Teflon tape, seen in the Guitar Stand blog post.  Great stuff.

We don’t want Teflon on the pointed end of the set screw, nor over the hex drive end either.

Threading the screw in from the bottom will leave the Teflon tape ‘out in front’ of the screw, tightening it up enough to keep from moving up into the body of the bridge, and lowering the string height, but will be soft enough to allow adjustment, with the proper tools.

For the shorter set screws used in the saddles, I cut the Teflon tape in half and started rolling.

One down, eleven more to go!  These set screws start fully flush with the bottom of the saddle rollers, so they can go in from the top.

This guy is ready to install.  Allowing for time to clean up the fingerprints, this took me about an hour and a half to get to this point.  Let’s string it up!

Oops.  The high E string was cut right in two.  Post-mortem analysis showed that there was a sharp edge on the tremolo hardware where the string ball sits.  Here, I’ve disassembled the tremolo assembly again to get a better look.

Sure enough, there is a very sharp edge on the hole in the tailpiece.  An appropriately-sized twist drill is just right to de-burr the sharp edge. The other string holes were fine.

I like to have a third party look at my work before the customer sees it, because another set of eyes and ears and hands may show a problem that I overlooked.  Jen gives the Jazzmaster a workout and is having too much fun!

Doctor Shoen is pleased with the results!  Check out doktorshoen on Soundcloud and check out his current project “The Voltage Drop” on Soundcloud, on Facebook, and in a club near you today!