Teflon tape at the nut

[arluk3]

Srick, I have learned from this thread that Teflon nuts are available. Well, Tusq XL nuts are said to be Teflon impregnated, whatever that means. I will try one of them. And I will make one myself from a block of white Teflon. I made a set of nut files (from feeler gauges, so they are very accurate). I suspect that the original bone nut in my guitar is too soft, because the strings stick even after I worked on the slots and used lubes. Of course I am not an expert and may have made numerous mistakes.

Some people say that the nut material only makes a difference when playing open chords. It is my opinion that, even when fretting a string, the string transfers energy to its termination (tuning machine, and the nut too), and that energy flows down the neck to the guitar body. If that much is true, then the acoustic impedance at the interface of the string with other materials will define the amount of energy which is either absorbed or reflected. The acoustic impedance equation includes the material densities and the speed of sound in each material. Maximum energy transfer occurs when the charactericstic impedance of materials is the same. Since the string material has both high density and high speed of sound, the nut material should have the same density and speed of sound for maximum energy transmission. The tuning machine already has high density and speed of sound, being made of metal. These factors apply to longitudinal waves (compression waves) only. The strings vibrate with transverse (side-to-side) waves which eventually reach the string terminations and reflect, but some of that energy must transfer into the termination.

In my experiments, in which I used Teflon tape to free up sticking strings, the sound of the guitar changed quite a bit. The speed of the waves (transverse, not longitudinal) in the strings above the nut was higher when the tension was higher, even at the same frequency. The speed of the waves is a function of tension, rather than frequency. By relieving some of that tension with Teflon tape, the waves would slow down for any given frequency, and the tension above and below the nut would equalize. Changing the speed of the waves would change the time of arrival at the termination. Does the change in tension somehow account for the change in sound of the guitar?

Do we have a physicist onboard who can explain why freeing up a sticking string appears to improve the sound of a guitar?

[srick]

Originally Posted by arluk3

I have a theory about how this happened. Before using the Teflon tape, I think the tension from the tuners to the nut was not equal to the tension from the nut to the saddle. What I mean is, the friction caused tension to build up in the headstock area until the string slipped (an squeaked often). I am guessing that the increased tension resulted in a less-than-ideal transmission of acoustic energy to the headstock, and to the body of the guitar via the neck. I believe that the increased tension of the string changed the freqencies which had propagated from the guitars strings, spoiling the stew. Once the tensions were equalized, using Teflon tape, the energy from the guitar strings passed into the headstock unadulterated, thus improving the sound of the guitar. It's only a theory. Would somebody please shed light on this? And, please, would somebody try this and report the results?

To go back to your theory, a well cut nut has a smooth, narrow bearing point (providing little friction) and this should achieve the goal of equal tension.

[GuitarLuva]

I first tried a black tusq xl nut a couple years ago and was so impressed with its form and function that every guitar I had and ever will have will have one. It's a cheap and easy mod. No more nut sauce or anything else.

[arluk3]

Update: thanks for the input, GuitarLuva and others. I have since made a nut from Tusq XL (Graphtech), and I find that my strings are still sticking. My nut slots are the same diameter as the strings, as I was very careful about such tolerances, and that might be defeating the teflon impregnated nut material. So I added a piece of teflon tape at the nut and now my strings are free again. Not pretty, but I don't care. I am very happy with the sound of my guitar, especially the incredible sustain and harmonics that were not present with the stock guitar. I am sold on Tusq XL nuts and teflon tape, and I am still ignorant about how these things worked their magic.

[GuitarLuva]

Originally Posted by arluk3

Update: thanks for the input, GuitarLuva and others. I have since made a nut from Tusq XL (Graphtech), and I find that my strings are still sticking. My nut slots are the same diameter as the strings, as I was very careful about such tolerances, and that might be defeating the teflon impregnated nut material. So I added a piece of teflon tape at the nut and now my strings are free again. Not pretty, but I don't care. I am very happy with the sound of my guitar, especially the incredible sustain and harmonics that were not present with the stock guitar. I am sold on Tusq XL nuts and teflon tape, and I am still ignorant about how these things worked their magic.

Just curious since you said you made a nut did you buy a blank and than prep it yourself or did you buy a slotted nut? It's important either way that you file each slot at an angle to the string post it's going to. There's no way a string should bind on a teflon coated nut. Honestly dude what you're describing would drive me crazy.

[Earl49]

Originally Posted by arluk3

..... have a HP 3561a spectrum analyzer that I could use to detect any differences that result from using Teflon tape, and maybe I will do some experiments when I have more time.......I believe that animals do appreciate good music. My previous cat loved to listen to Puccini. My current cat always leaves the room when I pick up my guitar, so he too has sensibilities when it comes to music, and he is completely lacking in empathy with respect to my feelings.

Good methodology, and subjective answers are probably all that you need. A graph showing couple of dB difference in the 5th harmonic of your note is a nice picture, but your ear already told you what you needed to know.

My cat comes running when he hears my guitar or my wife's flute. It is less about music appreciation though than, "If you have time to do that, you have time to pet ME". I have a friend who plays Native American wood flutes, but has a fairly strident style and plays loudly. The cat runs whenever this friend plays flute.

Straying off topic: When I first had access to an FFT analyzer and a new acoustic piano, it was easy enough to look up the published frequencies of each note. Spending a few bucks for a tuning mallet, I was all set to save some $$$ on regular piano tunings and do it myself. While I was able to get all of the strings tuned to the exact frequencies, the piano sounded terribly out of tune. There is more to it than pure tones.

[QUOTE=bausin;5916921The difference is not that much. IIRC, their hearing drops off around 23 KHz compared to humans 20 KHz.[/QUOTE]

Normal human hearing is 20 Hz - 20kHz for a healthy young ear. I'm not so sure that exists anymore with ear buds, loud TV's, and urban noises. There was a time when I could hear a particular frequency of about 23 kHz associated with the cathode tube of a TV, but I have not heard it since I was 13 or so??

[murrmac123]

Originally Posted by Earl49

Straying off topic: When I first had access to an FFT analyzer and a new acoustic piano, it was easy enough to look up the published frequencies of each note. Spending a few bucks for a tuning mallet, I was all set to save some $$$ on regular piano tunings and do it myself. While I was able to get all of the strings tuned to the exact frequencies, the piano sounded terribly out of tune. There is more to it than pure tones.

Indeed there is more to it when it comes to piano tuning, but stretch tuning doesn't really come into play as far as guitar tuning is concerned, given the limited 3 octave + range.

[arluk3]

In answer to GuitarLuva's question, I bought a blank Tusq XL nut and filed the slots myself. It took me about 6 hours to finish and fit the nut. I made my own files because the obscenely priced files that I could buy are mostly not even close to the string diameters. I had read all that I could about making nuts, and the angles to the strings, etc. I was surprised that some of the strings were still sticking, and I can only attribute it to tolerances that are too tight (perhaps). By the way, I also built an optical comparator for measuring the heights of strings above the frets, and it is accurate to .001" without having to touch the string being measured. And its very fast too, being able to measure all 6 strings at one fret in about a minute. It's especially useful when measuring the relief at the 13th fret. I honesty don't know how people take height measurements with feeler gauges, but maybe I am just a klutz.

[srick]

Originally Posted by arluk3

By the way, I also built an optical comparator for measuring the heights of strings above the frets, and it is accurate to .001" without having to touch the string being measured.

Sounds pretty interesting. Tell me more!

[GuitarLuva]

Originally Posted by arluk3

In answer to GuitarLuva's question, I bought a blank Tusq XL nut and filed the slots myself. It took me about 6 hours to finish and fit the nut. I made my own files because the obscenely priced files that I could buy are mostly not even close to the string diameters. I had read all that I could about making nuts, and the angles to the strings, etc. I was surprised that some of the strings were still sticking, and I can only attribute it to tolerances that are too tight (perhaps). By the way, I also built an optical comparator for measuring the heights of strings above the frets, and it is accurate to .001" without having to touch the string being measured. And its very fast too, being able to measure all 6 strings at one fret in about a minute. It's especially useful when measuring the relief at the 13th fret. I honesty don't know how people take height measurements with feeler gauges, but maybe I am just a klutz.

Now I must say you have me baffled. I don't understand how an acoustic guitar with a teflon coated nut could be causing strings to bind. I would say you have another issue only you said putting teflon tape across the nut slots cures the problem. What kind of crazy music are you playing on that thing to cause string binding like that on an acoustic guitar?

[arluk3]

In answer to GuitarLuva, my slots are tight. For a G string measuring .021" diameter, I made a file that was .021" diameter, and cut a slot that was that diameter for only a short distance near the front of the nut, opening up and angling toward the tuner. Other strings were handled in a similar fashion. I don't know how a piece of teflon tape managed to fit in there, but it solved my sticking issue. I don't understand it, but I am more perplexed by the sound of the guitar after sticking is solved. I listened to a stock version of my guitar the other day at the store and I couldn't believe it was the same guitar. I don't know if it had sticking issues too, but I know that it didn't have a Tusq Xl nut. Thanks for telling me about Tusq XL.

In answer to Srick's question, I built an optical device that has a mirror, comparator, and light source. It rests on two adjacent frets above the string in question. The image shows a scale imposed on the string, showing the height of the bottom of the string. I would like to patent the device, but I don't want to go through the patent process again, and patents can be defeated anyway. I have considered buying a 3D printer and making these things. Guitar techs who have seen and used it call it "amazing".

[GuitarLuva]

Originally Posted by arluk3

In answer to GuitarLuva, my slots are tight. For a G string measuring .021" diameter, I made a file that was .021" diameter, and cut a slot that was that diameter for only a short distance near the front of the nut, opening up and angling toward the tuner. Other strings were handled in a similar fashion. I don't know how a piece of teflon tape managed to fit in there, but it solved my sticking issue. I don't understand it, but I am more perplexed by the sound of the guitar after sticking is solved. I listened to a stock version of my guitar the other day at the store and I couldn't believe it was the same guitar. I don't know if it had sticking issues too, but I know that it didn't have a Tusq Xl nut. Thanks for telling me about Tusq XL.

In answer to Srick's question, I built an optical device that has a mirror, comparator, and light source. It rests on two adjacent frets above the string in question. The image shows a scale imposed on the string, showing the height of the bottom of the string. I would like to patent the device, but I don't want to go through the patent process again, and patents can be defeated anyway. I have considered buying a 3D printer and making these things. Guitar techs who have seen and used it call it "amazing".

Try filing each slot slightly larger than your string gauge and you shouldn't get any binding. That gadget you made sounds interesting.

[murrmac123]

Originally Posted by arluk3

I honesty don't know how people take height measurements with feeler gauges.

Me neither.

I use pin gauges, which are accurate to .001" , in conjunction with a 26" straight edge which sits in the nut slot and on top of the saddle. Doesn't get any more accurate than that.

[srick]

Originally Posted by arluk3

In answer to Srick's question, I built an optical device that has a mirror, comparator, and light source. It rests on two adjacent frets above the string in question. The image shows a scale imposed on the string, showing the height of the bottom of the string. I would like to patent the device, but I don't want to go through the patent process again, and patents can be defeated anyway. I have considered buying a 3D printer and making these things. Guitar techs who have seen and used it call it "amazing".

You should give StewMac a call. They would take a deep cut out of your profit, but it would pretty much eliminate the hassle of trying to patent and sell the little beasties on your own.

[murrmac123]

Originally Posted by arluk3

In answer to Srick's question, I built an optical device that has a mirror, comparator, and light source. It rests on two adjacent frets above the string in question. The image shows a scale imposed on the string, showing the height of the bottom of the string. I would like to patent the device, but I don't want to go through the patent process again, and patents can be defeated anyway. I have considered buying a 3D printer and making these things. Guitar techs who have seen and used it call it "amazing".

Presumably you still have the device ?

How about taking a picture of it in action and posting it here?