T.I.R. reading help

[flashbang]

I have a brain fart in writing the decimal for my spindle tir. I replaced my spindle bearings on my SX3 and measured the R8 taper with a 0-15-0 DTI indicator with .0005 graduations. My indicator is moving half way between one .0005 graduation, that is to say, one half of a half a thousandth.

Two things, what is the correct decimal fro this reading? and is this considered good?

Thanks for any help.

[MrWild]

.00025 Yeah, that's pretty good

[Crevice Reamer]

A half of a half would be a quarter, or .00025. For an SX3, yes that is pretty good. To put that into perspective, the average plastic grocery bag is .0005 thick.

CR.

[knudsen]

Not that anyone here minds answering questions, or of course the "sanity check" when you just don't believe yourself, but...

You could do the math by hand or with a calculator:

.0005
x 1/2
_____

~or~

.0005
x .5
_____
.00025

yup, that's not bad at all. I'll bet a lot of high end US made stuff is out a lot farther than that.

Now that you have something to measure that is less than the resolution of you DTI, you have a perfectly good excuse to blow some dough on a new digital something to measure with