Hi Ken, you are truly an inspiration and I have recently acquired my holy grail, a 96 Parker Fly deluxe in black! I was curious about the cable truss rod design--if I understood correctly, it seems that that is a one-way truss rod design, since you are limited by the threading of the nut to apply compression force and you can relieve that by unscrewing the nut back to its 0 position. is this correct? If so, curious why you didn't design it as a two-way truss rod, and your take on that design and if you deem it necessary for guitars?

I'm not a builder but a player. I love these videos. It gives me so much more appreciation for the art of building and the factors and variable that go into making one.

This is profoundly informative and interesting. Almost all the guitar players I encounter have a conception of what music is that is imitative and not creative; they want to "play like" and "sound like" (their words) this or that guitarist somewhere in the past -- recent or distant. It's a sort of performance/play-acting re-creation (nothing wrong with that) that calls for a genre-correct instrument even at the expense of accuracy, stability, and reliability. When I first picked up my Fly, I could easily feel the next-level design and fabrication. At a tactile level, the neck was simply perfect in all respects... up and down and all across the fretboard, and the body of the neck as well. And it felt better than even the most beautifully made wood and lacquer necks of the several $$$ guitars I own. It's an instrument that feels as though you can play anything on it. I realize this comment sounds gushing, but I consider these things to be self-evident.

Hi, Ken im 62yrs old just had a heart attack but thats life. I have begun my journey learning to play guitar. Love your video's they have a calming effect. I also love diy i am fitting a bathroom. Do yo spend a lot of time looking for tools when you put them down. I spend more time looking for them instead of using the bloody tools.😂

Starting the neck profile at the top edge of the fretboard vs the bottom edge is a subtle detail only a player would notice. I mod stock necks for my builds. The C profile builds tend to have the profile start at the top edge, as I sand the neck and fretboard as one (as you are doing here in this video). But most of my builds are trapezoid profiles. I used to start the trapezoid profile at the top edge of the fretboard, but only did it on one neck as I recall. Now I start the trapezoid profile at the bottom of the fretboard, round the edge at the neck/fretboard seam, and roll the fretboard edges. With the trapezoid profile, the only real contact points are the left thumb on the spine of the neck, and the left fingers doing the fretting, so the player never really touches the side of the fretboard.

Couple thoughts about further testing perceived string stiffness. 1. With the straight string pull across the nut on a fly headstock (as opposed to angled pulls on the vast majority of instruments), and particularly with a vertical string displacement which reduces the break angle over the nut during the test and keeps the string in line with the nut slots, the longitudinal stiffness will be determined by the entire length of the string from the tuner to the saddle. Additionally, the vertical displacement is the opposite vector of fretting a string and 90 degrees off from bending a string, both motions that would change the relationship of the string to the nut. These things could explain the minimal effect of changing the break angle. Testing the stiffness by pushing down as in fretting or pulling across as in note bending may yield a different result. 2. It would be interesting to perform the tests again with different headstock/tuning peg arrangements. With string pulls that angle laterally away from the nut slots instead of straight like the fly headstock, the increased friction at the nut may be enough to reduce the effective string length to be between the nut and saddle. The reduced string length should increase the tension required for string displacement. However, just as with the straight string pull, because the effective string length is the primary factor, increasing the break angle at the nut will likely have only minor effect. Once the friction threshold to shorten the string is achieved, the break angle will do little to change the tension between the nut and saddle.

Hi Ken, This a another excellent video. I keep looking forward to each new one you post. I believe that there is a typo beginning at 6:16. The overlay reads that the neck has a 24.5", 622.3mm scale length. You say that it's a 25.5" scale length, which I'm pretty sure is correct...unless this is some special-case neck.

Happy new year Ken! You mentioned previously that you have some techniques for adjusting the neck profile if a customer has a particular preference; would you do that via sanding at this stage?

Thank you for the very quality production sir. This whole series has been so inspiring and enjoyable. I have magnificent Classic Fly in MH. It is the most vibrant and loud unplugged of any electric guitar ! Hard to put it down.

It’s just beautiful, just gorgeous back and sides !

Do you have issues sourcing that beautiful ebony or do you just have a supplier you trust. Seems hard to tell what one actually gets these days, where it originated, etc.

Too funny - I watched this video with my wife and we were both amused at the idea of the bowling ball vise. She says, “I’m sure he doesn’t _literally_ mean a bowling ball.” An hour later, I sit down with the latest American Lutherie magazine, and there are _several_ pictures of one, including on the back cover! 😂 In his article, James Condino says he has about $60 into his. 😄

I really appreciate you taking the time to share your process. Thank you very much. ☮️

I had to put my respirator on watching this. 😂

Happy New Year, Ken👍

ty for showing me how you work. I like it, and I picked up some usefull tips and tricks:)

In Japan , Ken would be considered a National Treasure .

2:32 disaster struck lol. My tool held up for a good while have to say, but when I was doing some rather tough work with it the insert came loose. I think it's because of the type of solder I've used. See that you use a silver bearing solder, only now. I'm gonna go with a solder which bears 3% silver, as that is not too expensive stuff. my tool held up until now with copper solder.

all your work is fine and ingenious… how beautiful! thanks for your masterclass

🫶 for sharing your art! Love the sound of ebony cut with sharp tool, too! An video editor made a mistake with text on screen at 6:18.

Ken- do you have a current source for good files? Since Nickelson went to other countries for manufacturing the quality is box store, not what they built their name on. I have tried them and found them terribly disappointing. Ideas to acquire worthy new files?

Thank you for this series.

Hello Ken, I am trying to create your tool. I have a 3d printer at my disposal. I was wondering if instead of using a wood piece to epoxy the file in would it be possible to use a 3d printed base ? If so could you provide measurement so I can model the base ? Thank you in advance :)

This is an amazing test setup. What Im really interested in is how what you called the "after length" has an impact if any on actual tension required of the string itself when tuned to pitch...

You really need to watch your knuckles, that exposed spinning blade can easily get if you slip.

I sent my Parker to VJ to have the electronics fixed. No easy task, but one of his associates did a fantastic job replacing the film wiring.

The fact that the string bending device bends to a fixed string displacement means that you are presumably not actually testing to a consistent bent-string pitch under each condition. You would need an adjustable bending device, and bend the string until the same pitch (string tension) is reached for each headstock angle and post-nut string length. Which will show that the string needs to be bent further when effective string stiffness is lower (with less headstock angle and longer post-nut string length). Then you could measure the "finger" force at that consistent pitch on your scale (the result of the string tension and string angle).

Fantastic ! ♥

VJ just passed this video along to me and I’m so glad to see this test fixture is still in use! I designed and built it (atleast the first version of it, though it didn’t change that drastically) during my Masters program in the middle of Covid in my basement shop. It’s really cool to see the changes and upgrades you have made to the system for your own needs! I really like the change to the single screw system with the reinforced head. I didn’t do that in fear of the strength of the 3D printed materials I was working with at the time. I do admit that it was super difficult to keep even and stop the whole pice from rotating and binding in the channels. Also love to see the added ease of use with thumb screws and other pieces here and there! If there are any questions I’d be happy to answer any too!

Nice little plane you use on that bridge. I'll be needing one of those😁✌️&💙 and the other benefit I see to that round gouge is that it's an In-Cannel which seems like it would make getting a "flat" a little easier! Awesome.

Is that a Ticonderoga Pencil? Those are the best wooden pencils ever. I like the Black triangle ones but the yellow ones are good too 😊 I absolutely love the channel Ken. Thank you for sharing your knowledge with us!✌️&💙

The other factor to consider is change in pitch when 'bending'. Does an equal change in pitch in two conditions (greater headstock angle or longer after length) correlate to equal force exerted or equal displacement of the string? From a player's perspective "do I need to push harder when I bend with a greater headstock angle / shorter after length"? I'm sure you're already investigating that and I would love to see the results. What a brilliant way to quantify something that players have intuitively felt (and disagreed on for lack of objective data) for a long time.

Typically Baroque and Renaissance music does not use bending notes like used on guitars so the strings are not stretched as much and, of course, gut strings were used. Delrin is a poor choice for a nut as the wire wound strings will dig into it making it hard to tune. Incresing string tension by bending can cause the string to slide across the nut and change tuning. Fret positions have to be adjusted for the type of string and how far they are deflected to the fret since string tension changes with deflection.

Good fixture and testing ideas. I like how you can simulate Lutes! Some future investigations you can pursue with this aparatus: add the ability to simulate 3+3 headstocks (Gibson), reverse "Hendrix" 6-in-line (which just needs swapping string sizes by position), Scale Length changes (Gibson, PRS, Fender, Mandolin) and tuning stability. High Gibson headstock angles results in poor D-g tuning stability, many famous Les Paul players actually recorded in the studio with Telecasters because Teles keep great tuning stability. You should also measure "Sustain" of notes by string vs excess length beyond nut and saddles (Gibson D-g is poor vs E-e; Fender b-e is poor vs E-D; but that's reversed on Hendrix Style Strats, an important feature since most Metal players benefit from reversed Strat-style headstocks). You will find that Mandolins are very "plinky" due to having half their string length distributed beyond the nut and saddles vs headless and wrap-tail style electric guitars. The reason Gibson headstocks break so easily is because they based the LP/SG headstock on their main business of Mandolins, not sufficiently anticipating the increased tension on the longer scale length guitars. Put a load cell on the headstock adjustment arm to get an idea of the forward bending moment on the headstock for various headstock angles. Might even be interesting to compare headstock angle vs some sort of "Tone" measurement, using an electric guitar pickup and amp by string for different headstocks. I expect many guitar myths can be dispelled with this testing machine.

Now that is really interesting lads ! A rig like this could also be the perfect place to test a variety of pickups and different position. Is it something you'd be interested to test too ?

Interesting gizmo, but I have a question. Can't all this be simply calculated, through engineerings, instead of measuring? In that case the Lab Rats would be able to build a virtual simulator. I'm also concerned that the measurements are off when measurements are made by lifting the strings up on the poker, as that method significantly changes the break angle across the nut.

So, I see the jig or test fixture thing and I see how you can put the plastic stick with the scale and you can change the headstock angle but what exactly do you gain from all of the work and expense? Did you not already know if the headstock angle was increased the perceived string tension would increase? Don't misunderstand, I am a nerdy on geeky guitar stuff, but I am not sure what you gain in the archtop building front by spending time and money on this project. Have you not already built a bunch of guitars as well as knowing what others did before and therefore know where to start? I could see someone in 200 years trying to recreate a guitar with no wood using something like this except something you can play rather than just say "at this angle the pressure of a G string at the 5th fret is x-pounds to push the string y-millimeters" not sure if there is anything practical here. So, choose a headstock angle between 9 to 12 degrees and build guitars right? Just not sure what you learn from this which translates into real world building knowledge.

I immediately thought about lute headstocks. I'm glad you were too. I didn't expect much difference from that extreme headstock angle, but what I was wondering was if it was necessary because of the fact that they were using sheep gut strings and therefore needed a more extreme break angle. Still wondering. Hopefully you'll get some sheep before the machine comes back. :)

Three by three tuners?

Interesting experiment, and I always love your constant efforts at understanding and improving guitars. I believe other comments below echo my thoughts. This headstock angle is all about the force down at the nut and how much that reduces the strings propensity to slide over the nut. If we start with the notion that if the string were totally fixed at the bridge and the nut, then the tension required to displace the string is dictated by the 1. distance of displacement, 2. string material of construction, ie youngs modulus (stress vs strain in the elastic regime of the material) and 3. the geometry of the string... diameter, windings etc. 4. String tension or pitch. With all those items fixed a longer scale length will reduce the force required to move the string. Essentially you are measuring the effect of a longer scale length by virtue of the string sliding over the nut. I would think that minimizing the break angle at the headstock will give you a reduced string fretting pressure. As an instrument maker, the limiting factor is buzz at the nut. Set the headstock break angle at the minimum required to eliminate open string fret buzz. If you never play open strings, don't worry about it. ;-)

I never knew the man, but his design and building are the best.

Aluminum tonewood, lovely 😂

My father passed away today. He liked watching these videos with me.

It’s a ‘Lap-aluminium’

Why not just pull those old nasty uneven frets, level the board, re-fret the whole neck, level the frets, re-crown, bevel, micro file the ends to a nice round configuration, then proceed to high luster polishing. I do it to all the vintage rigs I do.

Zeroing the scale for each measurement seems tedious; perhaps an armature affixed to the frame with a dial indicator for distance, and a dedicated tension readout ,something along the lines of a neck jig, would eliminate the human error.

Interesting- Was it a smooth linear difference of 2% from 4-80 degrees? What I take away from this is that with only a 2% difference between 4 and 80 degrees (!), there is absolutely zero reason to argue, worry or further consider the differences between 12 degrees (classical guitar slotted headstock) and 15-17 degrees (Typical steel string guitar range) in building in regard to the feel of string tension, assuming the nut is slotted well with minimal friction. Yet...-What would be interesting is if you did a *blind* test with the right hand on the strings between the 4 and 80 degrees- if you could consistently feel that 2% difference with the hand then that would be more interesting for builders and players. But as it is, 2% over 4-80 degrees doesn't mean much to me from an empirical standpoint.

So is the conclusion that the angle does make a difference but that it's insignificant to playability? 2% seems negligible.

Thabnks for this episode and Merry Christmas!

Was it the lab rats that recently created the replacement ribbon cables for the original Flys?