#DIAL CALIPER SERIES#

001'.ДЄlso, I had heard that in calibration of instruments, the calibrating instrument or standard had to have at least a tenfold or better accuracy than the expected accuracy of the instrument being calibrated. Not bad for an instrument that is normally only read to the nearest. If I remember correctly three standard deviations gives you a confidence level of 99% so you're pretty darn sure your reading is within +.00045/-.00015 of the actual value. 0002' you would have an average error of +.00015' and a standard deviation of.00011. 002' high? If so, I would question the reason why they are so far off nominal when the remainder of the measurements are within. I don't know the temperature range over which an imported pair of calipers are accurate but I'm OK with using mine from 60 deg F to 80 deg F.Д¬lick to expand.Are your 2 and 3 inch measurements meant to be. And regarding vernier calipers, why would anyone not trust these instruments to be just as accurate as a vernier height gage ?'ДЇYI: the consensus of the majority of machinists was pretty much in agreement with the above although there were a few that disagreed violently, LOL.Д®dit to add: I wouldn't trust dial calipers to be accurate when measuring large dimensions in cold temperatures. And remember these are cheap $15 imports, not Mitutoyos. If so, then the above calipers would be acceptable to measure within. Perhaps an 'acceptable' scale of accuracy might be three times the tolerances being measured ? This certainly doesn't satisfy the suggested ten times accuracy. However it is not unusual to make measurements in the order of. This is certainly no problem using micrometers when tolerances are on the order of. Metrology texts suggest that a measurement instrument should have an accuracy/repeatability of ten times better than the accuracy requirement of the part being measured. 0003, following good practice like wiping the jaws and checking zero before making a measurement. The first number is the gage block dimension, followed by the caliper measurement:ДЄpparently I could trust the accuracy/repeatability of these particular dial calipers - in a clean environment at a reasonable temperature- to within.

#DIAL CALIPER SERIES#

I wiped the jaws clean and then measured a series of gage blocks twice, recording the error as closely as I could interpolate from the dial (yeah I know, this is sort of a visual crap shoot).

Just for grins, I went out to the shop and grabbed a $15 set from you know where that I use for WOODWORKING - measuring wood thickness to correct the planer depth setting. The opinion that dial calipers can be trusted only within some arbitrary number (usually much greater than. But they surely have their place and vernier calipers are reliable and tolerant of some uncleanliness. 'I read negative comments constantly regarding dial calipers and certainly some question exists as to repeatability and accuracy in a dirty environment. This was a raging argument six or eight months ago on PM and I put in my two cents there as follows: A post on another forum alluded to the inaccuracy of calipers.

Dial caliper