The Parallel Node, Calfee

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Kathy/Dan

Taken this latest information/explaination would it not be better for our muzzle devices/tuners be in the form of a tight fitting sleeve?. Like those currently fitted to high quality, target grade, pellet rifles.

Currently most of our devices/tuners are held in position by two screws squeezing the barrel. These two screws are usually no more than 1/2 inch apart.

A sleeve could run any length down the barrel. Would that not provide the weight needed and be better able to keep the muzzle at the last length of the bore inline rather than exhibiting a curve?

Half an inch verse many??
 
First, I am not speaking for Mr. Calfee, as that would be very foolish on my part. And most importantly, I do not represent myself as an expert on tuners. I can only explain what I meant and what I thought I understood from Bill's drawings.

I have used two types of tuners. The first is the commercial type such as those sold by Mr. Hoehn. The second is a homemade version that is also two pieces. All of you know how the first type attaches and works. The second type has an internal sleeve of steel whose inside profile along its length matches the taper of the barrel. This sleeve is a force fit on the barrel. The outer weight is then positioned by trial and error based on shooting results. It is my impression from the way tuners I have used react, that they provide two different effects.

The first is provided by their mass. It serves to make the area near the muzzle be the end of the curve or ocsillation through which the barrel moves, much like someone holding the end of a jump rope when it is swung.

The second effect is provided by the sleeved portion (the tighter and more perfectly round as possible the better). It provides resistance to that ocsillation curve continuing to the muzzle. In other words, the sleeve stops the curve imparted by the ocsillation at the back of the sleeve, leaving the remaining bore length within the sleeve straight and level as though held by an outside force.

I wish I understood more about how rail guns react, because their barrel sleeve mounting probably has a similar effect, essentially making the barrel shorter from a vibration perspective.

If I am totally off base in my assumptions, I won't be surpised, just tell me. I am very uncomfortable putting these thoughts out here.

I'll go back to the safety of my bystanders hole in the wall now.

regards,
Dan
 
Not quite.

Lynn, Dan, and Bill Calfee:

You guys are 90 degrees off. The nodes are points which do not move, and are most definitely not at 90 degrees and 270 degrees. You might want to look at your model again.

SteveM.
 
Lynn offered an explanation of the mathematical "position" of various parts of a wave, or a shape along a line of reference. Not speaking for him but agreeing with him I assume he meant that if you have a wave form that travels above and below a reference line, the point of origin is zero, the first apex is 90 degrees, the next point where it crosses zero is 180 and so on.

If you look at my explanation, and the drawing that Mr. Calfee originally offered in Precision Shooting, you'll see that his idea (and the one hat I understand) of the barrel oscillation begins at zero, and alternately travels above the reference and below, but only crosses the reference line at the end.

I guess this means that it goes from zero to 180 in a vertical direction with both positive and negative value, but with what I would describe as only one half cycle in the length of the barrel. I also guess that there will be resonance of the barrel material, i.e ringing like a bell, that would have higher cyclical frequencies, but with respect to the actual movement of the muzzle, the resulting tuned barrel moves effectively one half cycle vertically and horizontally with respect to an axis described by the bore line.

I am unable to look at any model, as I don't have one. The question I have for you is what you mean by the node being fixed? I guess I assume this can't be since the node I am describing is the null point at the bore line that is effectively moved to the muzzle by a tuner device. Am I wrong or am I not understanding your question? I've tried to describe my idea of how the muzzle moves without getting bogged down by the use of terms.

I really don't care to describe the movement using this convention. I prefer to describe it's travel and the fact that if the barrel without a tuning device has a null point (with respect to movement) that is not at the muzzle, the properly sized and placed tuner will effectively place the null point at the rear of the tuner, thus aligning the muzzle.

In general what I find most frustrating about this discussion is that it appears clear that tuners really work, but the controversy is over whether someone can explain why.
 
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Lynn:

Thanks for the sanity check.

I took hold of Mr. Calfee's "theorem" not because of his description, but because the drawings of what he believed was happening were consistant with what happened to my own guns. Also, the article that sold me on it is now 4 years old, and he had not yet converted to the thinking that once set, the tuner works for all loads. I have not yet expanded my thinking to encompass that.

I believe he may be shooting himself in the foot with some of the more engineering minded around here who, because of training, are compelled (not out of malice) to poke holes in his explanation because of his confusing use
(mis-use) of related terms.

I seem to identify with explanations I can see, so what he was suggesting didn't seem out of line. I tend to translate his use of parallel node to other terms that make sense to me, such as the null or point where the oscillation crosses the center axis. I may have done this without even thinking about it.

I may also tend to take his suggestions as gospel more easily than others. I don't build guns, except my own. I don't market my services or ideas, and I don't officially compete, so it is easy for me to take stock in his concepts. I have nothing to lose, and am not in competition with him.

So if he is wrong, and I am wrong, it's not a big deal for me. It is more important for others.

regards,
Dan
 
You see, BC asked the "engineering folk" to answer a trick question. It's an old "I don't know but it works" type question. You see he didn't ask any therapists, psychologists, psychiatrists, or even bartenders. Those of you that stood by BC were duped just as much as BC. The engineering folk just did what they were asked. I didn't ask. You sometimes get what you deserve.

Carp
 
Null points and nodes

The nodes are located wherever the oscillation curve passes through the neutral axis. Relative to the axis barrel, they do not move. However, these locations are points, not straight sections of barrel. A piece of steel cannot go from oscillating to perfectly straight and parallel to the barrel axis at one of these nodes. To simplify a bit, I'll use a common Newtonian quote - for every action, there is an equal and opposite reaction. If the barrel is under the node at a location to the left of the node, it must be above the barrel to the right of the node. (In the absence of an externally applied force). A muzzle device or tuner cannot be considered an externally applied force. It becomes part of the vibration equilibrium once it has been attached to the barrel.

Tuners, muzzle devices, etc. can dampen these vibrations, but cannot instantaneously "stop" them and create a straight section of barrel on either side of a node.

SteveM.
 
well

this whole thread could be made into a movie
"When Engineers Attack" i can see 'em circling
Bill better get in the boat.
 
Friend Dan

Friend Dan:

I got up this morining and read the new posts on this thread....something didn't make sense.......

I then went back to my post #69 and re-read it....I have changed it. My intention was to place the quote of yours, that I termed the "Rosetta Stone", on the post twice....somehow my first quote of yours, by mistake, was from another postion of the same post.....sorry

I wish I knew how to put the quotes in the boxes like everyone else does..
I have to highlight them and drag them........??

A muzzle device and its function in increasing the chance for accuracy is so very simple....even I figured it out.....

My friends, I'd like to say one last thing on this thread: (this thread is way too big, I have never liked big old nasty threads....sorry) anyway, I have absolutely no desire to change anyone's mind about muzzle devices or the brand of beer they drink, or anything........life is too short....I post on this forum for the folks who are looking for answers....

I give my answer, and someone else can give their answer, then whoever asked the question can do with the answers as they wish. If they believe you, that's cool, if they believe me, that's cool too......

Finally my friends, there's a big Indoor Unlimited today and tomorrow....I got plenty of head cheeze and pepperjack........Oh, if the world don't end first, I should be testing one of Roger von Ahrens's new solid "muzzle devices along about mid week or so......I'm kinda excited as is Roger....

Your friend, Bill Calfee
 
Good Luck.

Bill:
Good luck and enjoy your match and food. Please remember, also, that it was you who started this thread, asking what seemed to be rhetorical questions of "engineers". Here is part of your original posting from the thread that you started.


"The parallel node: The reason a muzzle device does improve accuracy is because of what I have labled the "parallel node", in the vibration pattern of a rifle barrel, when fired.

If there was no "parallel node", a muzzle device (tuner) would have no, or very little affect, on accuracy.

A question: Please someone help me here: If the dead spot, in the vibration pattern of a rifle barrel, when fired, was X shaped, and if that X shaped node could be moved to the crown, with a muzzle device ( tuner), how would that improve accuracy?

My engineering friends....how could an X shaped node (dead spot) that was moved to the exit of the crown, improve accuracy?

My dear friends, this new muzzle device that Roger is developing may turn out to be something that is not workable......if the world don't end...we will know something in a few days....

Now, you engineering friends??

Your friend, Bill Calfee


Several of us have explained why there cannot be a straight, parallel section (unless it is infinitessimally short) in a vibrating rifle barrel. The answers to your supposed questions have been provided. You just simply refuse to believe the answers. You asked, we answered, you refuse to believe scientific fact.

If you don't like this type of thread, the solution is simple - don't start this kind of thread.

Good luck and have fun at your shoot.

SteveM.
 
Dan said:
Lynn offered an explanation of the mathematical "position" of various parts of a wave, or a shape along a line of reference. Not speaking for him but agreeing with him I assume he meant that if you have a wave form that travels above and below a reference line, the point of origin is zero, the first apex is 90 degrees, the next point where it crosses zero is 180 and so on.

If you look at my explanation, and the drawing that Mr. Calfee originally offered in Precision Shooting, you'll see that his idea (and the one hat I understand) of the barrel oscillation begins at zero, and alternately travels above the reference and below, but only crosses the reference line at the end.

I guess this means that it goes from zero to 180 in a vertical direction with both positive and negative value, but with what I would describe as only one half cycle in the length of the barrel. I also guess that there will be resonance of the barrel material, i.e ringing like a bell, that would have higher cyclical frequencies, but with respect to the actual movement of the muzzle, the resulting tuned barrel moves effectively one half cycle vertically and horizontally with respect to an axis described by the bore line.

I am unable to look at any model, as I don't have one. The question I have for you is what you mean by the node being fixed? I guess I assume this can't be since the node I am describing is the null point at the bore line that is effectively moved to the muzzle by a tuner device. Am I wrong or am I not understanding your question? I've tried to describe my idea of how the muzzle moves without getting bogged down by the use of terms.

I really don't care to describe the movement using this convention. I prefer to describe it's travel and the fact that if the barrel without a tuning device has a null point (with respect to movement) that is not at the muzzle, the properly sized and placed tuner will effectively place the null point at the rear of the tuner, thus aligning the muzzle.

In general what I find most frustrating about this discussion is that it appears clear that tuners really work, but the controversy is over whether someone can explain why.
Click to expand...
Well. Let's see if we can continue with this Sine Wave analogy.
Let's say that the untuned barrel at the point of bullet exit resembles the inverse Sine plot from 0° (y=0) through 90°(y=-1) to approx 200° (0<y<1).
What I and several other are saying is that at th 180° point y=0. Addition of a tuner moves the 180° crossing point to coincide with the muzzle - basically stretching the curve to match the barrel length.
But what Bill has been claiming is that from about 175° to 185° on this inverse sine/barrel model, y=0 in a straight line for several degrees(@175° y=0, @180° y=0, @185° y=0 and then resumes it's sine wave behavior. In the complete absence of any external support to cause this.

He contends that moving the center of this straight section to the muzzle is what results in the accuracy improvement. Not only does this straight line section not exist, but if it did, why move the center of it to the muzzle as opposed to the end of it. Why throw 1/2 of the parallel effect away by leaving it outside of the barrel where it can have no effect on the bullet rather than utilizing the entire "Parallel Node" to guide the bullet?

Well mainly I would guess it's because it's really only at that center point where the bore is back in line with the mean original centerline of the bore (allegedly "stopped"), and there is no "straight parallel section" to begin with. But this would then agree with centuries of information compiled into the study of physics, and would thus not be "new".And us "engineering" types would have nothing to bring the controversy to a boil with.:D Not nearly so many people would be in active study of the phenomenon, and tuners would still be only in the attention of the elite shooters.
 
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Kathy said:
I wish I knew how to put the quotes in the boxes like everyone else does..
Click to expand...
There is a small box at the lower right of each post that has "Quote" printed in it. Clicking on that box automatically puts the entire post into one of the quote boxes. If you do not wish to quote the entire post, parts of it can be edited out in the same manor that your own typed text can be edited.
If you wish to break the post into several quoted boxes you must put the "quote" tags around each section of text. The quote tags for the post of yours that I quoted here are QUOTE=Kathy;390778 with the [ brackets ] around the text of the tag, followed by the close quote tag /QUOTE also enclosed in the straight brackets. (This is more clearly illustrated when you go back to edit a post with quotes in it. And these tags are more easily put into place in multiple places by copy/pasting to the various positions. Just remember that each open quote also requires a close quote for it to format correctly.)

You're welcome, and good luck at the shoot.
 
X or Parallel

Isn't there a short section of the vibrating barrel, when the wave is nearing, at and leaving its peak, where the angle coming in and going out is shallow, and the barrel movement is at it's slowest? If so, this section might, for practical purposes, approximate a straight section of barrel. Then using a tuner and weight to move that section to the muzzle would improve accuracy. I'm no expert, and this might be hog wash, but maybe what we're looking for is not a straight or parallel section of the wave, but only something which approximates a straight section.
 
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--rock said:
Is it possible that there is a short section of barrel surrounding the point where the wave crosses the barrel axis where the angle is rather shallow. This might approximate a straight section of barrel and explain why tuners work. I'm no expert, but in my mind this works.
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LOL. Well the whole plot is "rather shallow" as it were with the maximum apex height being in the neighborhood of 0.005" or less - so yeah, points close to the node are going to be "close" to parallel. But in the benchrest accuracy department that still results in a measurable POI dispersion.

But your observation and question do provide a good example of why Bill might think that there is a true parallel section, as the amplitude on either side of the node would be small enough for ones fingers to be able to hold a vibrating barrel at the node and not attenuate the harmonics - making it seem as if one were not touching a section in motion. Giving the false impression that he node was indeed nearly as wide as ones fingers. Which is, as I recall, what he has claimed led him to that conclusion.
 
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Lynn said:
Jettmug and Vibe
If a barrel was a single pefect sine wave your spot on.A barrel however just like most things in life isn't a single perfect wave.
If you impose a second wave on top of the first wave and it is out of phase with the first wave you get a shape other than a perfect wave.The tuner is causing a reflection coefficient to be set up at the muzzle and the reflected wave is summing and reducing the fundamental.
Click to expand...
I have to assume you are speaking of a different harmonic added to the one under discussion. Let's keep it simple for now, as I think we will find that the amplitudes of the higher harmonics are even much smaller than the one being discussed. Also we haven't even started talking about the Bourdon tube effect of increased stiffness behind the bullet due to the high pressure propellant gasses. Which would cause our "wave" to have a constantly varying wavelength, and could throw the "node" all over the place.
 
To Vibe, Jetmugg and all others who have a problem with the term "parellel node",

If I understand you correctly, what I think you are saying is that the vibration's wavelength running through the barrel can never produce a "flat spot" at any point along it's curve,

Plus, that the term "node" would only be identifying one precise "point" along the curve of that wavelength, and not for any measurable distance.

Now, let me ask you this: if that "node" were to occur at a specific "point" along the vidrations wavelength so that if a line were to be drawn that would intersect that "node", but result in that line being absolutely "PARALLEL" with the bore of the barrel, couldn't one identify this "point" in LAYMAN TERMINOLOGY as being the "PARALLEL NODE", for sake of a better term, and still get their point across?

Have you guys ever "RUNG" a barrel?
 
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Dave Shattuck said:
To Vibe, Jetmugg and all others who have a problem with the term "parellel node",

If I understand you correctly, what I think you are saying is that the vibration's wavelength running through the barrel can never produce a "flat spot" at any point along it's curve,

Plus, that the term "node" would only be identifying one precise "point" along the curve of that wavelength, and not for any measurable distance.
Click to expand...
I can go with that.

Dave Shattuck said:
Now, let me ask you this: if that "node" were to occur at a specific "point" along the vibrations wavelength so that if a line were to be drawn that would intersect that "node", but result in that line being absolutely "PARALLEL" with the bore of the barrel, couldn't one identify this "point" in LAYMAN TERMINOLOGY as being the "PARALLEL NODE", for sake of a better term, and still get their point across?
Click to expand...
OK. All points on said wave are "parallel" with the bore, since it's the bore which is vibrating, or rather the tube surrounding it. So by definition it would have to be parallel with itself.
But if what you are asking is will there be a node point which when connected by a line from the chamber forms a line parallel with the intended flight path of the bullet, then yes there is. And in fact if that were what Bill has been so insistent upon in describing I would understand it and agree, crude as that description might be, it would be accurate. However he's pretty clear that that is not what he is describing. Insisting that there is a "center" to the parallel node implies (And I think he's actually stated it) that he thinks there are at least 3 points (beginning, middle and end)that describe a perfectly straight line at or near the muzzle which points in the direction of the intended path of the bullet. My best estimate from his various posts is that he thinks this line of points (or parallel node) is on the order of 1/2" to 3/4" long, or about the width of ones thumb and forefinger.

Dave Shattuck said:
Have you guys ever "RUNG" a barrel?
Click to expand...
Yep.
 
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Vibe,

If in fact you have "rung" a barrel, and done so without using some high-cost lab equipment, then you should understand how it might appear to the crude and under-educated layperson, like myself, who only has access to the most basic of equipment, like a $14.00 Stethoscope from Wallys-World and pencil, that there seems to be a "flat spot" occuring for approximately 3/4" to 1 1/2" in length along the vibrations wavelength.

Words, it's only Words (credit goes to DeVal Patrict, Gov. MA)
 
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I've been following this thread with interest. I am no expert, either in gun smithing or in engineering, but I certainly appreciate you guys mulling this over.

I work in website strategy/usability and understand that much is lacking in just the written word. Without the eye contact (or lack of), body language, tone of voice, etc., the reader can't tell if someone is being sarcastic, or just down-right nasty. Yeah, I know that some folks get into Bill bashing. So we slide around that and take in the good information.

I would bet that if you got Bill, Vibe, Lynn, Dave, JetMugg and the others sitting around a table, snacking on (Lord help us) head cheese and beer, this would be one heck of a lively conversation.

Bill, don't give up on the long threads. I'd like to hear more from you in reply to some of the objections to your theory. I understand that you've written a lot of articles on this subject, but this is a great opportunity for us non-gunsmith and non-engineer, .22 rf benchrest accuracy fanatics to learn.

Thanks to all of you.

Best,
Michael
 
Dave Shattuck said:
Vibe,

If in fact you have "rung" a barrel, and done so without using some high-cost lab equipment, then you should understand how it might appear to the crude and under-educated layperson, like myself, who only has access to the most basic of equipment, like a $14.00 Stethoscope from Wallys-World and pencil, that there seems to be a "flat spot" occurring for approximately 3/4" to 1 1/2" in length along the vibrations wavelength.

Words, it's only Words (credit goes to DeVal Patrict, Gov. MA)
Click to expand...
Well my stethoscope was only $5 from Harbor Freight, and yes there is a reduction in volume for a longer distance than just a point. But all that is well explained by the math, mechanics, and properties of materials involved. I still fail to see how the the two concepts conflict to the degree held among the posters.
 
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