Do wooden arms warp

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.

Should have written "I know how to calculate the temperature elevation", for my first sentence above. Q is in joules, a unit of energy. Thus Q. would be equal to the kinetic energy generated by friction between stylus and groove, a function also of velocity, because neither the stylus tip nor the groove can dissipate energy any other way, except as heat. (But that's the rub; some energy is probably dissipated in "stretching" the groove walls, too.) Being in biology has nothing to do with this; I never studied physics except in college, so I hope the above is correct.

You are going to have to make many assumptions to do this calculation. First the heat Q being dumped into the diamond stylus is at the same time being dissipated by the stylus assembly to its surroundings. This will involve the temp. difference between the diamond and its surroundings, geometry of system, heat conduction coefficient, heat capacity, etc. Probably best to determine the equilibrium temp empirically. Heat dissipation calculation involves a nasty partial differential eqn. Then there is the vinyl: it is moving, constantly exposing new room temp. vinyl.

The heat dumped into the stylus will equal its dissipation at its equilibrium temp.
Presumably the rest will be dumped into the vinyl. Temperature will depend on heat capacity of the vinyl and how fast it is conducted away (that nasty heat conduction eqn. again).

Now the heat generated Q as the result of friction, as has been already mentioned, depends on the pressure, coefficient of friction and velocity. Now the linear velocity is changing do to the change in radius of the record as it plays. Then there is the stylus velocity due to the music. Now this velocity is frequency dependent (increases linearly with frequency).

So, assumptions need to be made to calculate a ballpark figure: like an average stylus velocity. I would assume that the dissipation of heat from the stylus is small and can be ignored. With that we can assume that all the heat generated is dumped into the vinyl. Heat conduction in the vinyl is probably small enough that one can assume that for an instant all the heat is contained in a small volume (but how small?). That would have to be addressed since heat capacity calculations require a mass to calculate a temp. .

So, this simple little calculation turns out to be a bit of a sticky wicket.

Swamp walker, you're forgetting my friend was an officer.

The comment about a human being able to survive for 45 minutes at over 400 degrees fahrenheit has very little to do with wooden tonearms, as well as being untruthful. I suspect that in a sealed chamber, at that temperature, the first real breath and a human body would know that death is very close.

I believe the comment about the level of heat generated at the stylus/ vinyl interface during replay was made in counter to someone else's comment suggesting that movement within a wooden tonearm due to atmospheric variations would be sufficient as to make an accurate and stable cartridge setup with a wood-wanded tonearm, impossible, or even difficult, which is just not true. Someone laid out some figures about movement in wood without telling the whole story. First, different woods move different amounts. Second, wood movement occurs radially at a much higher rate than it does in a longitudinal direction. Making a tonearm wand that stays true to it's axis can be accomplished easily enough if care is taken. Change in length of a wooden tonearm wand is pretty much a non issue given the short length of the wand, the fact that it is stabilized, and that wood just does not move that much longitudinally.

Also, that significant heat is generated at the stylus is not really a problem. Who knows though.. maybe the next significant advances in cartridge technology will come with nano-liquid cooled cantilevers ;)