Dave Johnson [Schaff Piano Supply Co.] sent me the first sample of his
new 7/32" tubing. Beautiful rubber, but sized too large by about .010
to .015 inch. The ID measured about .221-.226 inch. For the ideal
grab of a 7/32" nipple, I estimate about .208-.214.
The old 7/32" rubber (the good stuff) measured generally speaking .213.
They can't hold really good tolerances on rubber tubing, but you don't
need it anyway. So my sample was loose on the nipples. That's just
the startup problems you get into when specifying a new product.
They'll have something shortly, I feel.
If anyone would like to test their own tubing for size, one way you
can do it quickly is to spray a little WD-40 liquid into a section of
tubing and then start fitting drill bits down into it. Since all
tubing has a curve, don't stick the drill in further than about 1/2",
and the fit should be bare snug. Then, in your mind, allow plus or
minus .010" ID variances, and you have it.