I’ve been trying to get my head around the VB2 method as outlined here and I have one or two little problems.
Firstly, why should it only work for dominant diamond wheels? The formula would seem to be generic.
Secondly (and much more importantly), unless I have read the formula incorrectly (quite possible!) it would seem to be unbalanced. By this I mean the units of measurement involved. If I can try and expand my meaning by describing the formula in uom (units of measurement) and then using the numbers given as examples, we get -
c/sec = [ (ms * c) / ms ] * T sec
37 / 4 seconds = [ (0.2 seconds * 37) / 1 second ] * T
Doing some basic algebra on the first above we end up with 1/sec = sec which would indicate an invalid formula. In order for it to be valid we should end up with sec = sec, or 1/sec = 1/sec, or some such.
The second simplifies down to
T = 1 / (0.2 * 4 seconds) or 1.25 (secs**-1)
Note: (secs**-1) means seconds to the power of minus one, or 1/seconds.
Perhaps the T is on the wrong side of the equation? In any case, something is wrong with this.
Even taking the simplified version t=1000 / (4 x 200 ) it doesn’t work out. Let’s put in the units here -
t = 1000 ms / (4 seconds * 200 ms)
Cancelling the ms uom we get
t = 1000/(800 seconds) = 1.25 (sec**-1) NOT 1.25 seconds.
In order to get a mathematically correct answer we need to invert the numbers - i.e. it should be 1/1.25 or 0.8.
I hope I have made myself understood. I just want to try and understand the method so I can learn to use it properly, but unless the math is right I guess there is little point.