This is a restart of a thread about repeatability and accuacy of the HF caliper.
Two articles are presently available that describe my best understanding of these calipers. The first
deals with just the caliper. I felt compelled to retract some of my conjecture related to extrapolted accuracy presented in versions 1 and 2 but added more related to repeatability and how it interacts with accuracy at values near zero.
These retractions may later be reversed when the work from ckelloug is done. He has Jo blocks and the background to clearly see the absolute accuracy of these calipers in the range of 0 to 4".
The second article is a 28 page monster which was coauthored by Larry Gill of the Yahoo group "shumatech" and myself.
It does talk a lot about the caliper but more from an internal standpoint. The shumatech DRO directly accesses the caliper's internal count. There is a display mode that permits the user to see this count.
One thing that should generate a nice little "fire storm" is the section on repeatability. The experiment suggests that if you use this internal number you can get a short term (i.e. less than 10 minute span) repeatability of ± 2 tenths rather than the adverstised ±5 tenths.
I welcome your questions and comments. No reason to stop at the present versions.