Luthier's Inspection Bench

I recently decided to close the small retail office space I've been using to meet customers for guitar repair consultations, pick-ups and drop-offs.  It represented a sizeable chunk of my operating costs, but more than that, I found myself losing a lot of time just driving to and from.  I couldn't do much actual repair work there and it seemed wasteful.

Having customers come to my home is okay, but I don't really like the idea of having to escort them to my tiny little basement shop. It's very crowded in there and having to remove my current projects from the bench to clear a space every time someone shows up is less than ideal.

I recalled the number of useful shop fixtures we managed to adapt from IKEA furniture when we were setting up the shop at Lee Valley, and had a look through the catalog. My idea was to build a small workbench that could sit in our front room. Something that wasn't too offensive-looking.

I found the Forhoja kitchen cart and realized it would work nicely with some additions. I made a full-length drawer for tools, a backsplash to carry a sliding base for an angle-poise office lamp, and an adjustable neck rest. So far it's working well.

Here's a short video: https://youtu.be/AWuBqj1HAT8

Making a Mandolin Armrest

Video detailing the construction process of an armrest in curly maple.

Making a Pyramid Guitar Bridge

A short video describing my process for making the pyramid-style guitar bridge used by C.F. Martin and other early American guitar makers.

You Just Can't Beat It. (Until you assemble it, that is).

Something a little different. I made a busking drum kit that fits into a suitcase.

Making Mosaic Rosettes

A short video describing my procedure for making decorative tiles for rosette inlays.

Feeding the buzz.

Nathan dropped by with his Ibanez RG series guitar. Last year we dressed it up with some gold hardware and a new Floyd Rose tremolo.  At the time we swapped out his pickups for a pair of used Ibanez humbuckers that were never quite satisfactory. Over the years Ibanez has come up with countless combinations of pickups and there is a dizzying array of wiring schematics on the web, not all of them useful.  Some require specialized model-specific switches to allow combinations of coil splitting, and series/parallel output.

As it turned out, the two humbuckers he'd acquired were designed for use in a model with a single coil in the middle position. They worked fine with a three position switch but in a 5-way situation they produced weird, buzzy, low-output tones.  It seems as if they were designed to always employ the now-nonexistent single coil in the circuit to boost the signal. 

For quietest possible operation, here's a thorough shielding job involving copper tape in every cavity. Recently I've been trying something new.  Shielding wisdom promote the idea of "star grounding", wherein every grounding wire is run to a common point connected to the ground lug on the output jack.  This reduces ambient hum from induced grounding loops.

 Most often the back of the volume pot is specified as the common point. This poses some challenges. There can be upwards of 7 different wires leading to the same surface, and the heat required to melt the solder and get a good joint on one wire will often loosen another! Very annoying.  It also complicates things if you need to switch out the volume pot.  I've been adding a screw near the pot to which I attach all the "permanent" wires from the different shielded cavities, the bridge and so on.  Encapsulated as it is within the copper cage, there seems to be no audible increase in hum.

We replaced the pickups with H4's from EMG, which looked right at home in the Ibanez.  The sound of the H4A alnico in the neck position was particularly gratifying and Nathan was very happy with the results.

An electronic puzzle.

I lean towards the "Keep it Simple" school of guitar electronics. Not that I have anything against instruments with all kinds of bells and whistles, mind you. It's just not something I've ever developed a powerful lust for. I guess that's why I like Telecasters. Give me a volume and a tone and I'm happy.

When Alfie Smith asked me to build him a guitar, his first concept involved having the signal go straight from the pickups through a four-way switch directly to the jack. He was interested to hear how the TV Jones Super'Tron pickups sounded unencumbered by any load from potentiometers and excess wiring. They sound great.

A Spartan control setup to be sure, but even this took some mental wrestling. The four-way switch yields:  Neck,  Neck+Bridge in series, Neck+Bridge in Parallel, and Bridge.  This is not the typical 4-way sequence, and it took several tries to accomplish. Guitar electronics forums are full of helpful diagrams, some of which work, and some of which are obviously untested speculation...

Alfie and I both knew he was going to want a volume pot.  It just makes sense for the kind of club and bar gigging he does. He was reluctant to sacrifice the direct output tone though, and suggested a three-way toggle switch to allow him to turn off the volume and go straight to the amp. He was also interested in adding a fixed tone setting, something like the "cocked wah" tone popular in some telecaster circles.

"Sure thing! I can throw a switch in."  No problem.  I should point out that I'm not a natural electronics whiz. Hand me a schematic and I can wire it up - I routinely switch pickups, replace pots and jacks, change out capacitors and go through miles of shielding tape as part of the repair side of my business. Designing guitar circuits is something else though. It's not intuitive.

There are wiring diagrams galore online but you won't find one with a toggle switch that gives a direct out option. Sometimes what seems like a simple request isn't so simple! Three-way toggles don't allow for three discrete settings. The middle position always produces a combination of the outside circuits. It took a minute or two of headscratching to realize that there was no way to wire one to allow a direct signal. It would always end up mixed with either the volume or the tone. Multi-pole Microswitches! (I hear someone holler)  But no. The same problem arises.

I came up with an idea.  What if I was to combine parts from two toggles?  I could add some pole pieces and broaden the palette of possibilites.

The standard switch is on the left and the Frankenstein is to the right. I stacked an extra leaf and insulator strip on each side. (A word of warning: the screws which go through the stack are insulated with a precisely sized plastic sleeve to keep them from contacting the leaves. I had to cut an extra piece for each screw to make up the difference and prevent them from shorting out which would be annoying in a guitar circuit. It would be extremely dangerous in a situation where the voltages are higher. )

I carefully oriented and bent the outside leaves so they only made contact when the switch was flipped to one side or the other.

This is how I work through electronics problems. Some people are gifted and see it all in their head. I need to physically diagram to visualize the possibilities. Several pages later I hit upon the right combination of couplings and contacts. It's kind of vexing that the direct out signal always falls in the central position. One would prefer it to be on the side, but it's the nature of the circuit.  The final form yields: Volume, Direct Out, Volume+Wah.

 That's a lot of spaghetti!  There's so much going on in a tight space. Heat-shrink tubing keeps the contacts from shorting.

Now there's far more choice, and yes - there is an audible difference in the direct signal. It's almost like a lead boost. (And could function that way if one set their volume and amp up accordingly.  I'm not so sure about the wah.  I used the 3.3k resistor and .01uF capacitor suggested by people in the know, but these aren't Tele bridge pickups. The effect might be a little too subtle and would probably benefit from experimenting with a higher value cap. We'll see.

Morin Khurr Plan

Okay.  You asked for it.

Lately I'm being inundated with requests for information about the morin khurr I put together several years ago. Every week there's at least one email from someone - all ages, from all walks of life, and from around the world.

Let's be clear. I'm not an expert in traditional morin khurr construction. I built only one, using techniques borrowed from guitar making. It's playable and the owner is very pleased with it.
There was no resource material available to me when I began the project, and I scaled the dimensions up from a photograph I found online. As luck would have it they were very close to those I later measured when I got my hands on an authentic instrument.

So far, of the many people who have contacted me about building them, I've only seen one person follow through and complete a morin khurr (it was amazing). 

I'm not going to teach you luthiery via email. It's just too difficult. If you're the inquisitive kind of person who wants to build an instrument you need to develop self-reliance and trust your instincts. I'm providing the basic dimensions but I'm leaving details and construction techniques up to the builder. This should be enough information for people with some experience building guitars, violins, or other stringed instruments to get started on a plan of their own. (Click on the image to enlarge and then you can right-click to save to your computer).

Total Length:  41.5"    1054mm

Width at bottom of box: 11-1/8"   282.5mm

Width at top: 8"   203mm

Box length: 12-1/14"   311mm

Neck, nut to body: 17-7/8"    452mm

String Length: nut to bridge: 22-5/16"  566mm

Neck width at body: 24mm 

Neck width at nut: 22 mm

Neck thickness: 22mm at nut tapers to 30mm at place where curve begins

Fingerboard thickness: 4mm (neck is flush with body plane, board is above it)

Nut height: 16mm to bottom of string

Bridge height: 35mm

Tailpiece length: 6"  150mm

Side depth: 92mm (no taper)

Plate thickness at edge:  4.5-5mm

rounded corner blocks inside

Top arching at the bridge rises to about 8mm

Soundpost about 7mm diameter

String spacing: 19mm at nut,  30mm at bridge. (outside edge to outside edge)

My current project is an electric with several unique design elements. It's a chambered solidbody made from Spanish cedar and I'm having a good time working with the customer to craft something that addresses his style of playing. I'll post an update when it's complete.

Cutting neck pockets by hand is really the only way to ensure the best possible fit. It's slow but satisfying work.