Anything made of wood 'breaths', nature made it that way. So, yes your arm could warp. The type wood that it is made from would determine such, plus the temperature and the humidity in its environment. Best to dump it and get something made of metal or ceramic materials.
In addition to warp, I would expect the wood to change dimension slightly as humidity and temperature change. That's how it is with musical instruments...
I hate to sound stupid or pedantic
You don't sound like either....
What you are saying is a simple fact of life and nature and you appear to have direct and close evidence of its immutability 😢
Unlike musical instruments....a tonearm is not appreciated for its tonal/dimensional changeability...but as is demonstrated by many design decisions made by audio manufacturers....science often plays second fiddle to 'sexiness'....😡
Honest, guys, this issue needs to be put to death. Whether "they" warp or not, and I don't doubt that wood tonearms are susceptible to warping, some wood tonearms are among the best I've ever heard, to include the Talea and the Reed. Vacuum tubes inevitably wear and change specs over time; do you wish to avoid vacuum tubes too, as a matter of principle? (Halcro, I know you prefer SS; that's not the point.) Cartridges wear out and change over time even while we are adoring them. Audio is an unstable hobby in general.
In the real world, modern tonearms are made by guys who do understand these properties of wood. Then the tonearms go to live in our air conditioned/heated living rooms; they don't sit outside in the rain. How much warpage over how much time is prohibitive? Does anyone really believe that a wood tonearm is warping at a rate that will ruin alignment and geometry within any period of time that makes this a real problem? Any evidence for that? Guys who don't like wood tonearms or who have some ax to grind regarding whatever metal tonearm he or she worships like to carp on this issue of "warpage". It's not a real world, real time issue. I don't really give a shit if my Reed has warped a tiny bit in the next 50 years. I have a wood Grace tonearm (which I just keep around for sentimental reasons) that looks by eye to be as straight and true as a piece of steel, after 30 or so years of living in a controlled humidity indoor environment. There are some theoretical advantages to a wooden arm wand in terms of dissipation of energy that can be said to be superior to metals, but I am not here to say that wood is superior to metal. I am just saying that wood is in the picture as an excellent material to use to build an arm wand, if the maker knows what he is doing. I have heard both carbon fiber and ceramic arm wands; they suck.
In 1972 I was at Audio Arts in Livermore, CA, the new hi-fi shop of Walt Davies, now of Last fame. Walt was just becoming an Audio Research dealer, and Bill Johnson was at the shop, delivering and setting up a complete ARC system. SP-3 pre-amp, D-51 and D-75 amps bi-amped on Magneplanar I-U's. The source was a Thorens TD-125 Mk.II with a Decca Blue cartridge, and the arm was Bill's prototype, which never went into production. It was a flat piece of wood, maybe 1" wide by 1/4-1/2" thick (if I remember correctly), like the old Grado. I paid for one when I bought my whole system from Walt, but had to settle for a Decca Unipivot when the ARC never materialized.
Carbon and cermic arm can sound great as well. It is not the material it is the implimentation. But I agree with you. Reed arms can sound great. But I wonder how much influence the type of wood has. Reed has lots of options on finish and wood type.
We talk a lot about positioning of the stylus in the record groove with utmost precision and accuracy- as in microns. It's hard to imagine a wooden tone arm holding a set up for more than a few hours. Maybe it can be more dimensionally stable if it is heavily varnished; but then it is no longer a purely wooden arm. Perhaps there are those who do not mind reviewing set up periodically to have that special sound that they want. Certain air bearing linear arms need periodic maintainence to remain at top performance.
they definitely age and even warp despite of implementation quality. 40...50 years vintage wood arms by no means can match the quality of ones made of metal or aluminium back then.
there's also nothing wrong using or not using tubes which is only upto consumer. i like lots of power and control where tubes are either inefficient or make no sense at all. it all comes from speakers you want to listen and than match the proper amp weather it's tube or transistor.
In response to Lewm - I was not having a pop at wooden arms, and my post was in essence inquisitorial as to what people have experienced. In other words I am surprised as to the heated nature of your response. I see the point that cartridges wear out (although they can be re-tipped) likewise other components as well, but I am umming and ahhing about a super arm like a Schroeder LT or a Durand, and it is in pursuance of this that I made the post.
having owned 8 wooden armed tone arms (Schroeder, Reed and Durand) the issue ignored here is how the wood is treated.....which, of course, is secret and proprietary for each manufacturer.
so to generalize about what wood is going to do or not do in terms of temperature and humidity or even time is simply wrong.
personally i'm agnostic about material, passionate about performance.
I deliberately over-reacted to stir up some responses. In fact, I totally agree with Mike. In my personal experience, Schroeder, Reed, and Durand tonearms are or can be just wonderful sounding. And they do last. (The dirty little secret is that Durand has lately eschewed the use of wood in their TOTL design, the Telos. Mike probably knows this.) So it's more fair and valid to target one's criticisms to specific tonearms, rather than to tar and feather the whole bunch of them. By that token, I apologize to lovers of carbon fiber and ceramic. (Ceramic? What tonearm is made of ceramic?)
Tony, good luck aligning your cartridge within "microns". That ought to keep you up at night.
Lohanimal, I never did think you were taking a pot shot; some of the responders were, though.
Not a problem. I rough in my set up with my eyes and then fine tune with my ears.
Lewm, cursing and discrediting other posters, and stating that the issue should "be put to death" does not sound like a way to stir up responses. I observed you do this in a number of other posts. It is a bit tiresome.
Why not stick with facts and introduce valid arguments? That should stimulate thoughtful discussion.
And when you lose your cool with nasty swipes at others, a simple apology is in order.
woods can be treated to be pretty much impervious to humidity/temperature issues that result in expansion and contraction of the material. That is not too hard to imagine thanks to chemistry.
I know. That's what I was saying. The wood can be coated with varnishes or other polymeric compounds to make it more dimensionally stable but then is it still really wood or is it a polymeric construction with a wood look?
And I was not generalizing, I was making a supposition about the nature of wood and its impact on set-up stability with the hopes that someone who has actual experience with a wooden tonearm would comment. Some have commented that they sound great; but we want to know more. Its not a criticism. Everything in Audio has tradeoffs and if wooden tonearms sound really good but need to have the set up tweaked now and then, so be it. Many of us in this hobby aren't expecting plug n play then forget it. It fact, we live for the opposite.
Let's hear from someone whose own wooden arm has actually warped.
No anecdotal stuff, please.
The only wood arm I have ever owned (and still do) is that inexpensive
one which used to be sold on Audiogon for a couple hundred bucks. If
any wood arm is likely to warp, that's certainly a candidate. I just
eyeballed it and it's still straight and true.
(Yeah, my eyeballs are probably crooked and need to be recalibrated.)
Whatever, I can't believe this is actually worth umpteen posts. And
here I'm adding to the total :-)
Redglove, It is I who must take exception to your ad hominem attack. I made no "nasty swipe" at anyone here, but you have made a nasty swipe at me. As to making rational fact-based arguments, no one here, least of all me, has denied that wood tonearms have the potential to warp, depending upon how they are made and upon the environment in which they are subsequently used. Beyond that, the issue is "how much" and does it affect alignment such that wood tonearms need to be frequently re-aligned. I think I addressed some of those issues, but my only data set is my personal experience. Since there is no "science" of wood tonearms per se, the rest of it is just my opinion vs the opinions of others. I actually enjoy trading pros and cons with those whose opinions differ from mine. And I cannot apologize to you for anything I've already written here or anywhere else on the Analog Forum. If the very word "shit" offends you per se, you're entitled to feel that way, I guess.
There are wood armwands and then there are wood armwands. As Rockitman stated, woods can be treated to such an extent that they are essentially impervious to warpage from aging, moisture and temperature changes. Warpage in wood is a function of the change in tension between the different grains. Each grain having a different density and moisture content, hence a different shrinkage (hate it when that happens)factor. By choosing the properly aged/dried wood with the desired grain pattern, wood is the optimal choice for an armwand. (All bets are off if the wood is green.) I know this statement will bring out all kinds of challenges. No matter what I say or write, I doubt I will change anyone's opinion on this topic. Nor do I care to try. I will say, IMHO, nothing in use today isolates the energy from the motor/plinth getting to the cartridge better than a proper wood armwand. No other arm material I have heard is as neutral. If there were better available, I would be using it. It certainly would cost less and save many hours to make a metal armwand than a properly prepared wood armwand.
One poster suggested wood expands so much that it will change their precise to the micron cartridge setup. Thanks for the laugh, and that is on so many different levels. First of all, cured/kiln dried wood in general has a lower expansion rate when compared to most metals. It is the moisture in the wood that expands, not so much the wood itself. Low moisture content hardwood has about a third of the expansion rate of aluminum and magnesium and half compared to titanium when the temperature range for testing is in the realm of our real world environments. Stabilized wood(where the moisture is vacuumed out and replaced with other materials) performs even better. Then lets talk about the thermal properties of vinyl. It expands and moves around at a rate about the same as aluminum. The problem is the heat generated by dragging the record grooves against the stylus generates huge temperature swings. How much heat is contested but 500 degrees F peaks might be conservative. There goes those micronic adjustments.
Disclaimer, I build the Schröder LT tonearms.
No matter which side you take, have a great Holiday!
Mr V. So you admit your tonearms are plastic with a wood look. Just as I surmised. How else to maintain dimensional stability? It was never about temperature, our turntables sit indoors. At least mine does. The challenge with wood is changes in humidity. The only solution is to infuse the wood with other materials. So at best it is a wood/polymer hybrid. And what does the localized heating between the stylus and vinyl have to do with tonearm dimensional stability? Try to organize your thoughts better.
Still the open question: How well do wooden tonearms hold their setup? Does anyone have some facts?
Where do you come up with that conclusion Mr t? No plastic here. Is English a second language for you or are you just trying to justify your misconceptions?
Hmm. Applying the Liberal strategy: When lacking facts and data deflect with personal attacks.
Let me ask another question then. If wood is neutral then why are musical instruments made of wood? Different woods give instruments their character, no?
Tonywinsc- Try reading what Vetterone wrote again, s l o w l y
If there were better available, I would be using it. It certainly would cost less and save many hours to make a metal armwand than a properly prepared wood armwand.
Oh wait, I wouldn't want to confuse a conservative with the facts...
I guess some of us are getting a woodie from this intense conversation. Now THAT kind of woodie does warp over time for sure. (That's just to be funny, Redglobe. I hope "woodie" does not offend you.) It might be helpful to go back to the question posed by my friend Dopogue; has anyone here actually had an experience wherein his wood tonearm warped or changed shape to such a degree that there was a misalignment detectable with a protractor (even at the micron level)? If so, I would like to hear details.
Vetterone, I did not know that the Schroeder LT is made right here in the great American Northwest. That's cool. It's on my wish list.
Tony, I don't know why you take such a purist approach. All materials have plusses and minuses for this use. If one takes steps during manufacture to ameliorate the negatives of a particular material, such as sealing wood or impregnating it or whatever, why does that negate the argument that wood tonearms are not or need not be problematic? By the same token, then, it would be out of bounds to dampen a solid metal arm wand so as to minimize its tendency to develop resonant peaks (if such were the case). And Vetterone has correctly pointed out that most metals will also warp to one degree or another, in response to heat and humidity changes.
The main advantage from a wood arm, you can hear the weather change before you can see it. And you know when your wife did open the window and did no telly you. But, we all know, there is a Fan out there for everything :-)
Before the Reed started their tonearm production they first
compared all kinds of different materials for the arm wand.
The conclusion was that wood is the best material for the
purpose (see: www.reed.lt ). I can't remember that Fletcher
ever stated: 'I made (a better) Breuer' ( aka 'The arm',
alias 'Sumiko 800'. Now that I at last got an decent
plinth for my SP-10 mk2 I don't need to tray again to
exachange whatever of my Glanz carts for the plinth made
by my friend Vetterone. He always refused for some reasons.
But now that he reproduces some (wooden)German tonearm
in the USA I may have a better chance?
Despite my earlier naysaying, this thread has had at least one positive outcome. It made me dig out my old 12" cherry wood tonearm, bought here on Audigon for either $200 or $250, and stick a Denon 301II on it. The Denon has been languishing unplayed and so had the tonearm. The combo is now making beautiful music together on my much-modded (by Jean Nantais) Lenco L75.
Happy holidays to all.
Oh yeah, no warping.
A hornets nest if ever there was one. Thanks Vetterone. As person who has worked with wood I personally think that it has amazing qualities - natural fibrous structure? check sufficient structural inconsistency to prevent single dominant resonance frequency? check, Light? check? strong? check.
That said I know from experience with woodwork it can be a complete pain in the backside - the worst being getting sufficiently rested planks, and the correct grain.
Just because it is used in musical instruments so as to resonate, it can also be used to get rid of resonance and channel it away - I know a custom guitar builder and he's forgotten far more than I will ever know on this. Bear in mind that we can get hold of carbon fibre guitars, and if we want we can and do make metal instruments - so all things are capable of resonating so as to make sound.
I guess the best answer appears to be - in theory they can warp, but in the lifetime of those having owned such arms no such ocurance has ever happened and even if it does, it will be minimal given the wood selection and 'proprietary' treatment (I personally think the last one is total nonsense BTW) because wood warps over such a long time, and those treatments are highly unlikely to have been tested over 50 plus years
Rather than worry about warpage I personally would concern myself with whether the arm could get me to shake, rattle & roll. What's more important, a few microns or saving your doggone soul?
Hey, I wasn't trying to slam wooden tonearms. I was just asking questions. I have no experience with them so I was curious about any downsides to wooden arms. No one seems willing or able to answer my questions so I did a little research on wood. Here are a few facts: Wood changes dimensions with changes in relative humidity. What part of the tree and how the wood is cut greatly impacts dimension stability. Varnishes, paints and other coatings can slow but not stop the dimensional changes. Bamboo and Teak are much more stabile than Oak (by roughly a third). Now I did a rough calculation but keep in mind all of the variables cited above. A 9" long wand made from Teak wood might change length by 0.034" (870 microns) due to changes in relative humidity as the seasons change. That means, and this is all I was asking, that say you set up overhang, HTA and VTA in the summer when Relative Humidty is somewhat high. Come winter when the heat is on and the Relative Humidty drops the wooden arm will shrink causing a shift in setup. You will likely have to go back and recheck HTA and VTA. Is that the experience that some of you have had with your wooden tonearms? Again, not a slam just an analysis. It's all part of the hobby.
Hey, I wasn't trying to slam wooden tonearms. I was just asking questions. I have no experience with them so I was curious about any downsides to wooden arms==== Tonywinsc
Now, you got your questions answered.
If you do not have a wood tonearm go and get one and stop worrying about micron warps which if you are old as I am, you will not notice it with your naked eyes.
Go listen to your turntable and enjoy the music.
Syntax is an audiophile who is widely experienced with top quality equipment, so I take his opinions seriously. If you read this, Syntax, can you comment on instances in which you or a close friend (if you have never owned a wood tonearm yourself) found problems with a wood tonearm due specifically to the effect of humidity? That would be helpful. My agnosticism regarding wood tonearms is based on my personal experiences with two very good ones that after a couple of years have caused no such problems in my system. Alignment remains stable within the accuracy afforded by Dertonearm's Uni-Protractor. The temperature in my listening room remains between 68 and 72 F, year round, and the humidity is controlled by air conditioning. Beyond that, I certainly do not hear a difference in sonics between winter and summer.
No, but my wooden leg does, causing me to often fall over on my way home from the tavern late on a winter's night. Or, at least that is what I told me captain......arg!
Tonywinsc, you are applying the "conservative" effect of denying reality .
Reed likes wood and many other companies believe in their materials. Is reed the only company that knows how to make an arm? I don't think so.
I am but lowly wetland scientist, not a material scientist, but after some initial skepticism, I am now quite convinced by both theoretical and empirical evidence that wood's "instability" need not automatically disqualify it from being used in a perfectionist analog set-up:
Theoretical- metal also is dimensionally unstable and has a coefficient of thermal expansion that can be quite a bit higher than certain kinds of wood. Same is true for some ceramics. Assuming that the wood is properly dried, we see the following coefficients (units are 10 minus 6th inches change per inch length per degree F), rounded to the nearest whole unit:
Glass fiber/plastic 14
Fir (cross grain) 17
Oak quarter sawn 30
So if dimensional stability in terms of temperature change is the most important parameter, then diamond would be best. It's cheaper than unobtanium but it's a bitch to machine ;-)
The issue with respect to humidity is much more complex. My only comment is that I believe some wood tonearms are "stabilized" by impregnating the wood w resins or epoxies, not just by sealing the outside with a varnish or polyurethane finish.
Empirical- Others have noted that several of the finest tonearms wands are made of wood. We also see Lewm's report that his 2 wooden tonearms are dimensionally stable enough that over the course of 2 years, their alignment, when measured using the most precise (and most expensive) alignment jig currently available, has remained on the gnat's a$$ (my words not his). We also see that the physical properties of cartridges vary enough over time that in a highly resolving system, it is possible to hear changes in the sound with changes in VTA, VTF, and AS that are far less than anyone would previously have suspected.
As with most of these complex designs, esp. w transducers, it comes down to establishing design goals, optimizing the design to achieve those goals, and properly implementing the design. And then of course there is the subjectivity that the listener/user imparts to the process. So there will almost never be a single "best" material or "best" drive mechanism, or "best" stylus profile, or "best" circuit topology, etc., etc.
To get back to the OP's ?, the simple answer is that yes wooden tonearms can warp, but it appears that a properly designed, properly manufactured, and properly maintained tonearm wand can be made from wood, without warpage being a major constraint on its performance. However, I don't think I'd want to buy one if I lived in the Amazon ;-) Although now that I think about it, constant high temp and humidity is probably less harmful to alignment than the changing New England weather.
The question was 'Do wooden arms warp?' The answer seems
to be 'no problem at all'. The problem however seems to
be that we don't like simple answers while the philosophical
possibilties of the 'If... then' construction are endless.
Well I already own a cart with diamnod/stylus combo made
from one piece of diamond. What then can we expect 'if the
whole arm wand would be made from this material?'
The pseudo-intellectuals on this thread crack me up. A person with an analytical mind asks a question and gets attacked for asking the question; but no one offers any answers. Even better, someone like Mr. V can make non-sensical, ludicrous statements like this:
"The problem is the heat generated by dragging the record grooves against the stylus generates huge temperature swings. How much heat is contested but 500 degrees F peaks might be conservative. There goes those micronic adjustments. "
Yet no one questions that. I have been waiting to see if anyone would question this outrageous statement; but no one did. All the pseudo-intellectuals seem to accept his statement as fact. First, think logically about this statement. I have been playing records for almost 4 decades and I have yet to see one of my records burst into flames. Second, vinyl melts at 480F, so that would mean our records are melting and re-solidifying every time we play them. How long do you think a record would last under that kind of punishment? I'm sure the highs would be gone after the first play.
The facts are that the stylus exerts about 300-400 psi on the vinyl surface based on VTF and contact area. The coefficient of friction is about 0.22. Heating of the vinyl is going to be in the 18F range. Conclusion: It is perfectly safe to play your records indoors.
Bravo that someone can turn a pencil into a tonearm and receive accolades for it. But as in any hobby and in life, "Caveat Emptor".
Nobody would mistake Tony for an intellectual.
Tony, Notwithstanding all the other provocative elements of your last post, I don't think anyone has "attacked" the OP. The OP's rhetorical question elicited a lot of strong opinions on either side, but no one has directed any venom in his direction. Can you say where this really happened? I think the question he raised is a perfectly valid one, worth discussing in a civil manner. (Yes, I can be faulted for not being so civil, once or twice. Mea culpa.)
Tonyw- 300-400 psi seemed awfully low so I did the math. Someone please check it for me, but here is how I did the calculation:
According to Audio-technica's cartridge glossary @ http://eu.audio-technica.com/en/products/cartridges/glossary.asp#microline, a line contact stylus typically has a contact area of 50-75 square micrometers. Using the upper number, that converts to 0.0000087 sq. in. 1.8 gm VTF convert to 0.0634 lbs. So psi is 0.0634 lbs/0.0000087 sq. in or slightly over 7287 psi.
It's beyond my skill set to convert that to a temperature differential but if its a linear relationship, and if your other math is correct, then we are looking at a temp change of over 400 degrees. Of course, the total contact area is tiny and the mass of the surrounding vinyl quickly dissipates some of the heat so the vinyl does not "melt" or "burst into "flames"
And yes, there are some who say that the pressure and temperature stress is sufficient to cause the vinyl to deform; even advocating that LP not be replaced without some time to cool and rebound to their original shape.
Someone please check it for me, but here is how I did the calculation...
Michael (Swampwalker), thanks for (as usual) bringing some level-headed and intelligent perspective to this thread, as was evident in the conclusions you stated in your earlier post. But upon checking your math I see what appear to be a couple of incorrect calculations.
75 square micrometers/square microns = 1.16E-7 square inches.
1.8 gm = 0.0635 ounces (not pounds) = 0.00397 pounds.
0.00397 pounds/1.16E-7 square inches = 34224 psi, much higher than even you had calculated.
Although offhand I'm not totally certain that the 75 square micrometers is really that, or if it should be 75 micrometers squared = 5625 square micrometers, which corresponds to the square inch figure you used, and which would put the psi just slightly higher than what Tony had indicated. Can anyone else confirm that (as I suspect) 75 square micrometers is a reasonable figure for contact area?
Also, without doing further research I too have no knowledge of how to convert that to a temperature rise, or if Tony's assumption of a 0.22 coefficient of friction is accurate. FWIW, though, I recall that some time ago an article by Robert Harley in TAS cited the same 500 degree figure that was mentioned above by Vetterone.
And that's why I'm not an engineer, Al ;-) The actual verbiage copied from AT's web site is "Line Contact tips are also known as Shibata, providing a contact surface between 50 and 75 μm2". ZYX web site shows following spec:
3micro m x 60micro m
which I would interpret as having a contact area of 180 square micrometers.
If you look at Zev Audio's site @ https://sites.google.com/site/zevaudio/turt/stylus-shape-information
you see that line contact styli have a contact area of 47-62 square micrometers. Interestingly, elliptical styli have a much smaller surface area (21 square micrometers) and so would result in 3-4X the pressure and thus potentially even higher temperatures.
I haven't gone back and done the math but it's possible that TonyW (or his source) used the radii of one or more styli to compute the contact area. However, this is not correct. The contact area is not the same as the stylus dimensions.
Of course, this is way off-topic. My apologies to the OP.
A guy I knew from school was an Air Force Lieutenant who volunteered for an experiment at the medical research facility at Wright Patt AFB in Ohio, the experiment was to see how long he could stay in a heated chamber before signaling the experimenter to be let out. Dressed in street clothes he was in the Chamber at 425 F for 45 minutes. No big deal.
I am a life long woodworker, and have extensive extensive experience with many different species of woods. I have built nearly 1600 plinths for the LP12, the Garrard 301/401, and the Thorens TD124. I made the armwands for the Teres Illius tonearm, and have been working on a tonearm design of the past several years. I also build instruments as a hobby.
Wood is a great material for a tonearm wand, what separates the end results, are exactly what wood is chosen, species, grain orientation, age, moisture content, how it is worked, and how it is finished.
Some woods are more susceptible to continuous change corresponding with environmental changes than others. Some wood species, if there is no internal tension, are very stable after the sap moisture in the wood has come to relative equilibrium. Changes in relative humidity have less of an effect on some of these woods. Internal tensions can be mostly sorted out in the wood selection stage, and can be very effectively further checked in the preparation stages of turning the wood into arm wands, or whatever.
Quality instrument makers prepare neck blanks by rough milling, and then storing them. Then years later, roughing out the neck shape, cutting the neck top plane, and neck sides, then leting the blanks 'rest' again. After some time, if the blank has proven itself to be stable, it is finished into a neck. This is a relaible method for taking the factor of warpage out of a wooden item like a tonearm wand.
Vacuum wood stabilization is very effective in checking wood movement, as well as increasing the damping factor in a given wood. To someone above who questioned the 'integrity' or 'ethics' of stabilizing wood, or whether or not stabilization with vacuum impregnated polymers turns the wood into plastic, no, it is still wood. And how many metal arms out there that employ some sort of damping strategy to reach a desired end result? Many top instrument builders say that the finish actually does more than just protect the wood, that the finish is part of the synergy that comes together in tempering an instruments 'sound'. The changes that occur to a piece of wood that is vacuum stabilized, still leave the treated piece of wood well within the range of mechanical characteristics that make wood a desirable material to work with, only more stable, and perhaps with more desirable sonic characteristics, in the case of a tonearm wand.
I have one of those Cherry tonearms that were sold here on agon, it was given to me by a customer who I built a deck for . It IS warped. However, it is clear from looking at it, that very little was done to prevent warpage. It is not stabilized, and it is not shaped in a way that would tend to prevent it from warping. To compare those Cherry tonearms with a Reed, or a Schroeder, is like comparing apples and oranges, it has no relation.
In questioning the OP's opening post, It is not necessarily that all wood warps. In most any wood, a warp can be induced, but, in old, very well seasoned woods, the main reason for warpage is internal tensions within the wood. These tensions exist , mainly due to environmental conditions which the tree was subjected to while still alive, like living on a windward slope, exposed to high winds, uneven weight due to the tree leaning, tensions set due to heavy branches, and countless other individual circumstances.
Most likely, any wood that has been correctly stored and seasoned for many years, yet is still warping, either it is due to internal tension, or it is a species that is less stable.
In the case of Ebony, or Cocobolo, or similar extremely dense, and/ or resinous woods, no matter how long they have been seasoned, it is a good idea to let them rest again after rough milling to a dimension close to the final dimension, as moisture will only move through solid timbers of these species to a degree and no more. When they are cut into, they need to season some more so that the exposed bits can come to equilibrium.
Yes, it is very possible to make an item like a tonearm wand that will predictably hold it's shape, and not warp. The main factor is how carefully the piece is made, mainly in 'working with the wood' and not against it's nature.
Ilikmangos- thx for bringing some real world experience to this discussion.
Geoffkait- I was originally trained as a biologist and I'm a pretty good cook, so my bull$hit detector went off big time. Apparently the high temps cooked your friend's brain;-). It took about 5 millisec for Google to find the actual test results paper of the Wright Patterson experiments. The highest temp any of the men were exposed to was 158 degrees!
I know how to calculate the heat generated, but there are a few assumptions one has to make, and I am not so sure I know how to incorporate the assumptions. If you know the coefficient of friction between vinyl and diamond, and if we know the force per unit of area and the velocity of the stylus, we can calculate the energy generated. Then that energy can be assumed to heat both the vinyl and the diamond. So we need to use the first law of Thermodynamics, Q (Quantity of Heat) = m*C*dT, where m = mass, C = heat coefficient, dT = change in Temperature. Since diamond and vinyl will have two different values for C, we can make a guess as to which material would be heated to what temperature, assuming room temp as a starting point, by assuming that the energy will be apportioned between the two materials as dictated by their different C values. Molecular biologist or "molecular virologist" here, Swampwalker. But I don't know what this has to do with wood tonearms.
Swamp walker, you're forgetting my friend was an officer.