[sherline] Re: Subject: DRO accuracy

--- In CAD_CAM_EDM_DRO@egroups.com, Jon Elson <jmelson@a...> wrote:

>
>
> wanliker@a... wrote:
>
> > In a message dated 7/10/00 11:08:12 AM Mountain Daylight Time,
> > wanliker@a... writes:
> >
> > << Repeatability: .005/.01mm, >>
> > This should have been .0005
>
> Great! But, what about the TOUGH one? Resolution is easy,
> repeatability
> is harder, and you need both of these before you can even talk about
> ACCURACY. I note that a lot of the lower-cost digital calipers are
> not rated AT ALL for accuracy. I got an $80 Chinese-made caliper,

and

> it is less accurate than a VERY heavily used dial caliper that I've

been

>
> (ab)using for years. The error is only about .002 - .003" at the

worst,

>
> but that is significant.
>
> Jon

That's is called "chinese", one thing that I've learned is never
buy a measure instrument made in CHINA!
I've a Mitutoyo caliper"Digimatic" and a B&S electronic Micrometer,
I've being using the caliper for the last 2 years,on a every day basis
(6 days a week) +- 300 measuremnts per day(I'm a cnc operator)and
it's still going and going and going!
it's still holding the 0.0005" accuracy after 2 years!(Shure I've
taken good care of it).many of the other operators have the dial
caliper and they are all off by about0.001" from wear on the tip of
it.
Don't skip on price when it comes to measure instruments.
Mitutoyo claims + or -0.001" accuracy,but i check mine every week
with a 1" gage and a micrometer and it's right on!no + or - but the
exact gage diameter!
I'm using the caliper to check for possitioning of the table of my
minimill and would recomend for those who are thinking in get a
linear scale for that purpose.