"Maybe somebody who really knows will jump in."--David Doggett,
http://steelguitarforum.com/Forum5/HTML/007821-2.html
Happy to.
I finally got around to reading the entire thread, including the links to back pages.
The above link covers pretty much all the history, beginning with cogent responses by Chas Smith, David Doggett, and Jeff Smith, on page 3, who knows quite a lot about it.
But my statements here will eventually get back to the topic, which is tuning the pedal steel, and the problems I have been able to glean from posts. Bear with me.
Trying to figure out what is generally meant by steelers re sharp or flat thirds, I have these facts about the equal temperament. All thirds are sharp from just, fourths are similarly 'wide', and 5ths are 'narrow'.
Take the third; as b0b says, the ratio is 5/4. This means that the 5th harmonic of F coincides with the 4th harmonic of A. (A tuner will then flat the F by about 7 beats per second.)
Why? If I were to tune the intervals F-A, A-C#, and C#-F 'beatless', or justly tuned, I would not end up with an octave; the hi F would be flat from the lo F.
And we know how the circle of 5ths, all tuned beatless, doesn't come out with the same starting pitch. To do that, you must narrow the fifths and widen the fourths (from beatless).
Tuning wars are not solely the purvue of steel players; among piano tuners, there are 'A' tuners and 'C' tuners. A tuners start with an A and tune the F to an ideal third beat rate; C tuners tune the F for an ideal 5th beat rate. They do not agree.
I used two forks (now two notes from a Kord tuner), C, for me, and A, for guitar and violin players, since I tuned lots of studios, symphonies, and bands.
Being a piano player, I like a strong 5th, a slower beating than a true ET. Right away there is a compromise involved. That is, my progression of thirds is not perfect, but my fifths work very well in ensembles. As I tune up the scale, I check my 13ths (an octave + a fifth) and tune them beatless, which maintains strong fifths, and the stretch is implied.
Electric pianos: there are 12 pots, so the entire piano is governed by that.
An electronic, 'sampled' piano, is sampled (from a concert class grand) at each octave; thus you get the 'stretch.'
I think you can draw your own conclusions.
The pedal steel's temperament is over its 10- or 12-string compass. Thus, to accommodate the natural sounding stretch, how you play is involved. You set your thirds to accommodate that, you place your bar, say an octave up, to accommodate that, with your ear.
And so, it's different, piano to steel, in that your technique accommodates your aural preferences, as a string player accommodates to accompany a singer or a piano, in the case of a concerto.
But no matter how you tune, a third will be wide of beatless, JI or ET.
It's more personal with a steel; thus I conclude you're all doing it right. Each steel is different, each ear is different.
This is brief, but I hope it helps.