My precision reference came today, it's the DMMCheck Plus r5. Being somewhat impatient I wanted to see how close my meters were. Clear evidence of temp coefficients - the calibration data lists 68 deg F as the conditions, but since it's about 20F outside right now, despite the package being in the house (nominal 68F) for a few hours, between the static bag and the layers of bubble wrap, the unit was quite cold to the touch, probably 40F or lower. So knowing I was going to get incorrect readings until everything warmed up, I went ahead anyway.
8060 DC volts and amps - bang on within specs. AC volts reads high, AC amps reads high. Resistance values bang on, within specs. Frequency perfect, cal says 100.006157Hz, meter reads 100.01.
Switched over to the 45, DC volts and amps bang on within spec, ac volts high, ac amps high, 10K and 100K resistance high, 1K and 100 ohm low, frequency high. But by now it was obvious the DMMCheck was warming up, as the AC volts was fluctuating downward, every few seconds one less LSD, closer and closer to the actual value.
So I'll try it all again tomorrow once everything has had a chance to stabilize in temp (and I will also power the meters on well ahead of time as well, the 45 at least says minimum 1 hour, I don't think the 8060 specifies a full hour before checking cal, but it too will be allowed to run for a while before making any comparisons and then I will see if either or both of these meters need adjustment. I also need to dig out my 8012 and check that.
Is there a lesson here? I KNOW I'm doing it completely wrong, and the results are pretty meaningless - but that it's even close and is another bunch of datapoints otherwise not obtainable is meaningful. Plus it bodes well for when I DO do it the right way. If it's reasonably close under improper conditions, it shouldn't be wildly off when everything is right.