Building a Table Tennis Racket

We got a table tennis table at work and it revived my old enthusiasm for the sport.  I played in the 90's and I had a semi-custom paddle and everything.  I wasn't very good but I enjoyed the hell outta it.

So naturally, given that I have a bunch of raw materials left over from building my composite guitar neck, I decided to embark on a journey:  making my own wood/composite table tennis blade.  Naturally this is going to turn out more expensive than simply having bought one from a store.  But I guess that's not why I do this stuff.

First, a picture of a sandwich discovered on my little blue camera chip thing.  I got a message from my HP 735 3.2MP 15x Photosmart camera that I'm running low on solid state storage.

I don't want to lose this.  It's a metaphor for composite laminates:

Next, I assembled materials.  The black plastic sheeting is part of a garbage bag, laid on top of an old mirror which I hope will provide flatness.  The basswood sheets I have are only 4" wide and so I'm going to have to butt them against each other in a sort of alternating layer thing.  The book is to push down on top.  Good book, BTW, if you like solving "Mate in X" puzzles...lots and lots of them:

Next I put some wood down on the plastic, then a layer of fiberglass fabric on the wood:

Then I had a sandwich containing three layers of wood plus two of fiberglass, soaked in resin.  Yum:

I added weight:

I let it cure overnight and prepared to cut the shape of the blade:

And I ended up with a slightly-too-flexible paddle that has epoxy puddles in the gaps where the butt-joined layers meet:

Not good enough.  It's got enough rigidity in the long direction, I believe, but it flexes a bit too much across.  I think that's because there are two long joints in the middle.  I should have done two layers joined at the edges and only one joined in the middle, but I did it other way around.

I've ordered more wood and when it comes we'll use this one as a template.

The Meaning of Phrygian #6 - What I Missed

In my last post I went through convulsions to derive the so-called Phrygian #6 from the major scale by means of an involved process.  I left for later the question of what Phrygian #6 actually means.  


I turns out you have to do is get the Phrygian mode and do what it says - sharp the 6th degree.


1. C Major scale with # of semitones between each degree:

       C   D   E   F   G   A   B   C
         2   2   1   2   2   2   1

2.  The 3rd mode of the major scale is the Phrygian:

       E   F   G   A   B   C   D   E 
         1   2   2   2   1   2   2


3. Sharp the 6th degree to "slide" the one-semitone interval over one degree:


       E   F   G   A   B   C#  D   E 
         1   2   2   2   2   1   2


4. Transpose to D:


       D   Eb  F   G   A   B   C   D
         1   2   2   2   2   1   2


Having said that, I don't really like Phrygian #6.  I wanted the regular Phrygian after all, because it sounds like it goes with my riffs better:


       D   Eb  F   G   A   Bb  C   D
         1   2   2   2   1   2   2

Building a D Phrygian #6 Scale

Yesterday I played around with a couple of power chord riffs in standard drop D that have root notes at frets 0, 1, 3, 5 and 7 (D, Eb, F, G and A).  I got to thinking, what is that scale?  So I went to JGuitar.com, which totally rocks, and set up my tuning to Drop D, then set the root note of the Scale Calculator to D and started calculating different scales until I found one that fit:  D Phrygian #6!

Of course, how could I have forgotten?  Good old Phrygian Sharp Six.  I wanted to understand where that name comes from, so I searched for it and found this at Marc Sabatella's site.  Mr. Sabatella writes:

There is no common term for the second mode of the melodic minor scale. 

It doesn't tell me where the name comes from, but it is what I need to derive this thing from first principles without twisting in the wind for hours:

1.  C Major scale with # of semitones between each degree:

       C   D   E   F   G   A   B   C
         2   2   1   2   2   2   1

2.  The 6th mode (Aeolian mode) of the major scale is the natural minor:

       A   B   C   D   E   F   G   A
         2   1   2   2   1   2   2

3.  To make the harmonic minor out of the natural minor, raise the 7th scale degree one semitone.  The classical composers did this to be difficult make the 7th degree of the scale a proper lead tone, half a step away from the root.  So much for the mathematical precision of the "music of the spheres".  They were like, "Yeah that's a pretty good mode but you know what?  Doesn't sound right for my song here. Let's just change it."

       A   B   C   D   E   F   G#  A
         2   1   2   2   1   3   1

4.  OMG!  See that 3 semitone interval in there?  Ugh!  It sounds "unnatural"!  To remedy that, they make the harmonic minor into the melodic minor by means of another little tweak:  raising the 6th a semitone to "take up" the allegedly awkward-sounding 3 semitone leap between the 6th and 7th degrees.

        A   B   C   D   E   F#  G#  A
          2   1   2   2   2   2   1


Another thing:  that's the birth of a scale that contains two 1 semitone intervals that are only a single 2 semitone interval apart.  Scales built from natural or harmonic minor scales don't have that pattern.  Scales built from modes of the melodic minor scale do have that pattern.  Useful side effect of all that goofing off with the minor scale.  So next time you have a partial scale that goes "half-whole-half" and you start searching for a name, and you find yourself in a sea of Altered Locrians and Phrygian #6 goofiness, it might help to remember that you're simply perhaps in some mode of the melodic minor.
And finally:  in the classical approach, you only play that when you ascend.  You play the natural minor when you descend.  Dicks.
Oh wait one more thing:  When you read about minor scales to find chord progressions that go with them, you are given a whole pile of options.  Where do they come from?  It's all the chords that are diatonic to both the natural and melodic (and sometimes the harmonic) minors, chucked into a bucket.

5.  The 2nd mode of this one-way scale is sometimes called the Phrygian #6 for some reason - that's for another time:

       B   C   D   E   F#  G#  A   B
         1   2   2   2   2   1   2 

6.  Transposed to my chosen root of D, because that's the lowest, coolest note of a guitar in drop D:

       D   Eb  F   G   A   B   C   D
         1   2   2   2   2   1   2 


Note: It was helpful to bring in the flats instead of the sharps, to keep the accidental count as low as possible.  Since the riffs I'm playing only contain the first 5 notes, the question of whether I want to have A go to B or A go to Bb is up to me, and I haven't decided on that yet.  That will be a totally different scale!

Straight Pull Headstock Conversion, "Finished" but Unfinished

I still have to adjust the nut slots and tweak the bridge and saddle, but this guitar is now playable in its new 3+3 straight pull configuration.  We'll see about stability and durability.  Here's a detail of the headstock with its battle scars.  The new bone nut is in place, and the Sperzel tuners.

Here's the whole guitar:

Acoustic Guitar Straight Pull Conversion

Straight pull means that the strings, when viewed from directly above, come over the guitar nut and drop to the tuner shafts without an divergence to the left or right.  Fender electrics often have this arrangement, but it's far less common on 3+3 style headstocks.  And I'll show you why.

For what purpose do I wish to do this?  I've seen differing opinions, some of them strong.  And the person in that link has a point.  In any case, when the guitar nut is viewed as a dimensionless line, the string is only going in one direction:  either it goes over the nut and straight "down" to the tuner, or it goes over the nut and "left/down" or "right/down" to the tuner.  That's a fact.  But to my mind, that misses a couple of points:

1. Straight pull just seems like it ought to be better, facts be damned
2. I like how it looks
3. The argument fails to take into account the actual geometry of the guitar nut, which is a vertical slot cut into the nut material.  A string that goes straight "down" lays naturally in this slot.  A string that goes left or right as well angles down into the slot from the front edge of the nut, then makes another angle from the back of the nut slot to the tuner.

Anyhow I'm doing it.  If I screw this all up I'll simply saw off the headstock at the scarf joint and glue on another piece, or something.

First job is to determine the natural lie of the strings.  I haven't been able to figure out a good way of doing this, really.  I figure close is good enough for this cheap acoustic.

No, wait.  The first job is to plug up the four holes that will be moved.  I used 3/8" oak dowel glued in with that same hardcore two part epoxy I used to do the fiberglass layers on my electric.

Then I put tape across the last inch of the end of the headstock, put the bridge pins in place, made a loop in a piece of string, hung it around each of the bridge pins in turn and ran it through the correct slot in the nut, and eyeballed a line on the tip of the headstock.  When the lines were pretty close to evenly spaced, I figured they were pretty close to correct (proportional string spacing or not).

Then I used a little piece of brass tubing from the torch tip cleaner kit that was almost the same diameter as the wrapping portion of the tuner shafts to mark the desired locations of the new holes.  This is hard because each of these 3/8" holes will interrupt valuable grain in the headstock material, inevitably weakening it.  So I staggered the hole locations.  

Drilling simple holes when you don't have a drill press can be an adventure as well.  Drill bits wander from starter holes; verticality becomes an issue.  I solved the wandering problem by making a template from a piece of steel stock:

Yes, really.  Then I measured from the holes to the desired edge of the headstock based on providing enough clearance for the tuner buttons to rotate.  I then made a silly flowing profile and attacked it with a coping saw, because a tilt-back guitar headstock is not easily amenable to cutting on a bandsaw.  Nice filled holes, huh?  This guitar is looking better and better every second.  

There are a million little holes on the back of the headstock where the old tuner mounting screws were removed, and where I misplaced the new tuner locator pin holes a million times.  Since strength is an issue here, I'm going to fill all the small holes with raw epoxy puddles.  I guess that should be strong, unless it's not.  I have the option of finishing the edge and face of the headstock with veneer to cover  up all the mess, but in order to do that I'd have to take away native grain and that concerns me.  I think this is just going to be an ugly guitar.

Proportionately Cutting a Guitar Nut, Cheap and Naive

I ordered a 1/4" blank bone nut from StewMac and decided to make my own.  I'd never done that before.  I cut it to length with a hacksaw and to shape with 100 grit laid on 1/4" plate glass.  I've read that 3/16" of bearing area is sufficient.

I cut it roughly to height with the hacksaw as well.  Since I knew that the original nut was a bit high, I used the one to draw a line on the other, placed the new nut in the jaws of the vise with just the discard area sticking up, and chopped it flush.

I used a tiny hobby triangle file to start the slots for strings 1 and 6.  Then I was faced with the problem of spacing the rest of the strings.  This was fun.  I wanted to space the strings proportionately, which means that instead of being spaced evenly on center, they will be spaced evenly based on the distance between their edges.  First, I needed a jig:

I obviously made that, and it was obviously cheap.  I put six nuts on a small threaded rod and used them to enforce my desired string spacing.  This works best, I think, on a traditional 3+3 setup lacking straight string pull. - the horizontal break angles pull the string into the adjustment nuts.

Then I calculated thusly:

1. 1 and 29/64" between the high and the low strings =  1.453125
2. The total diameter of strings 2 through 4 = 0.114
3. The total space to be divided among the remaining five string gaps = 1.339125
4. The amount of space between each string = 0.267825
5. Multiplied by 64 to make it 64ths = 17.1408

I thus attempted to put 17/64" between every string - that means diameter to diameter or what have you.  That way thicker strings get their share and fingers get the same amount of space around each string.  Is the better?  Who can tell?  Measuring was hard with my eyes.  Around a year ago I noticed that I have trouble at close range with tiny little 64ths of an inch.  Luckily, I found this weird lens in the junk drawer of my tool chest:

It's badly scratched but it actually worked well for this task.  Once I had the spacing, and believe me that (for me at least) committing to a measurement is a real act of faith, I marked each side of each string with a pencil.  Not an ordinary pencil, but a pencil sharpened on a flat sheet of sandpaper to make a knife edge.  

Then, as I said, I started each slot with a hobby file of small size and triangular cross section.  This is nerve wracking in itself:  I couldn't commit a deep cut until I was sure the groove had landed exactly between the two bracket lines.  When I'd cut deep enough to just touch both lines, and that contact occurred at the same time, I had confirmation that I'd hit the center properly.

Then I finished the slotting with a cheap set of welder's torch tip cleaners, a trick I'd found in several places on the internet.  I am unable to make the exact citation, and I do not know who originally proposed this solution.

They look like that.  I just picked the one that looked next-size-up from my string using my untrusty eyeballs and my fingers (important).  The large ones were able to hold up to the filing pressure, while the small ones need to be supported by your fingers wherever you can hold them.  I settled on one finger from my free hand on the edge of the nut, and one free finger from my filing hand pushing down on the file right where it crossed the nut.  It worked.

My next task will be more outlandish:  straight pull conversion.

Fred Edge Dressing, Cheap

This fretboard is bound by a strip of black plastic.  I could have taken this opportunity to trim the frets to size and snip their tangs to preserve the binding, like you might for a good guitar.  But I chose to extend the fret slots through the binding and do it the easy way.

You can get special tools to allow you to hammer frets over the body of the guitar, but why spend the money on that when you have a large hammer that can also be used for other things?  That big one at the bottom:  you can reach through the soundhole and support the fretboard with it.  It helped that the fret slots were generous in width for the StewMac fret tangs.

I trim the fret ends with a regular end cutter, not a fancy luthier's model.  My whole goal is to avoid buying specialized tools.  When I cut, I push the cutter against the fretboard and then pull it back just a hair, to prevent the fret from getting levered out of its slot by the unsteadiness of my hand as I apply pressure to the cutter handles.  

Then I was left with a row of spikes on both sides of my fretboard.  When I built the neck for the electric, I simply ran a mill file freehand down the sides.  The worst that happened there were a hand cramp, a bloody nick, and the occasional ding on the headstock when I ran the file too far that way.  The acoustic presents one new problem, however:  freehanding it is impossible because the file would repeatedly hit the guitar body where the fretboard goes over it.  

So I made a tool that consists of two clamps holding a mill file to the edge of a board.  The clamps are heavy, so I arranged them in opposite directions.  The file descends only 1/8" below the face of the board, which is run along the fingerboard.  It was heavy as hell but worked perfectly.

The black plastic binding took some damage so I sanded it down with progressively finer grits of paper until I'd taken off the damaged finish material and plastic fuzz.  It's visible but doesn't interfere with function.