Is there a way to verify the calibration of a pin-type moisture meter?
Yes. The meter is calibrated to read a certain percentage of moisture content (MC) when you put a known resistor across the needles. Each manufacturer has a slightly different resistance value. A full set of resistance values as a function of MC and species is in "Electric Moisture Meters for Wood" by Wm. James., U.S. Forest Products Lab Report FPL-GTR-6, 1988.
Gene Wengert, forum moderator
In other words, once in a while when I have completed a charge of red oak or soft maple, I'll oven-test wafers off of the samples (using two wafers - not sliced just off the edges either) to find out the exact sample moisture content.
Then I get to see just how my meter reacts to measuring the center segment of the sample.
I try and keep a piece or two laying around the office (which has 35 percent relative humidity) to use as a reference, if I doubt my meters for whatever reason.
It mentions in one of the notes for Table 1 that the resistance is measured in megohms. Some species would have a resistance of 200,000 megohms or higher. Is this correct, or are the resistances 200,000 ohms?