Also, when reporting Surface Profile (Form and Location) it is the value listed in the deviation column when textual analysis is applied.
Like this:
You are correct, sir.
FORMULAS:
T = SQRT ( XDev^2 + YDev^2 + ZDev^2 )
It is actually a little bit more than that if you are NOT using SNAP for your vector points or if you are using SURFACE points or EDGE points. If not using SNAP points, the vector values are included in the formula, BUT, the T value will ALWAYS show as if you used SNAP.
If you don't use snap, you COULD see something like this:
XNOM 0 XVector 0
YNOM 0 YVector 0
ZNOM 0 ZVector 1
This would be a point, straight up and down. Now, NO MACHINE is perfect, they ALL have some amount of drift, so your touch COULD be this (grossly exaggerated and in METRIC):
XACT 0.125
YACT -0.105
ZACT 1.124
No matter SNAP or no, your T deviation in this case will be 1.124, HOWEVER, if you trig it out (as some will do), you would think it would be 1.135, but that would NOT be along the vector of the point
SQRT (0.125^2 + -0.105^2 + 1.124^2) = 1.135
When done using the vectors, well, ZERO times anything is zero, so:
SQRT ( (0.125*0)^2 + (-0.105*0)^2 + (1.124*1)^2) ) = 1.124
the 1.124 is what the T value will ALWAYS be in this example, BUT, by using SNAP (which put the actual reading back on the perfect vector line), it removes the drift from all 3 axis. Now, some will say this hides a sloppy machine, and yes, it can, BUT, this example is a VERY exaggerated example of how much drift you might see. On my old (OLD! 20+ years old) machine, I get less than 0.002" of drift and that really won't show up unless you are trying to hold micron values.
Also, when reporting Surface Profile (Form and Location) it is the value listed in the deviation column when textual analysis is applied.
Like this:
You are correct, sir.
FORMULAS:
T = SQRT ( XDev^2 + YDev^2 + ZDev^2 )
It is actually a little bit more than that if you are NOT using SNAP for your vector points or if you are using SURFACE points or EDGE points. If not using SNAP points, the vector values are included in the formula, BUT, the T value will ALWAYS show as if you used SNAP.
If you don't use snap, you COULD see something like this:
XNOM 0 XVector 0
YNOM 0 YVector 0
ZNOM 0 ZVector 1
This would be a point, straight up and down. Now, NO MACHINE is perfect, they ALL have some amount of drift, so your touch COULD be this (grossly exaggerated and in METRIC):
XACT 0.125
YACT -0.105
ZACT 1.124
No matter SNAP or no, your T deviation in this case will be 1.124, HOWEVER, if you trig it out (as some will do), you would think it would be 1.135, but that would NOT be along the vector of the point
SQRT (0.125^2 + -0.105^2 + 1.124^2) = 1.135
When done using the vectors, well, ZERO times anything is zero, so:
SQRT ( (0.125*0)^2 + (-0.105*0)^2 + (1.124*1)^2) ) = 1.124
the 1.124 is what the T value will ALWAYS be in this example, BUT, by using SNAP (which put the actual reading back on the perfect vector line), it removes the drift from all 3 axis. Now, some will say this hides a sloppy machine, and yes, it can, BUT, this example is a VERY exaggerated example of how much drift you might see. On my old (OLD! 20+ years old) machine, I get less than 0.002" of drift and that really won't show up unless you are trying to hold micron values.
