Understanding Moisture Meters

In last month's newsletter, we covered part 2 on our series concerning the nature of moisture in wood, and how to deal with it. This month, we are following up to with information about moisture meter types, for those who are considering the purchase of one of these tools for taking their woodworking to the next level.

Moisture meters usually fall into one of two types: pin style meters and pinless style meters. Let's take a look at how they perform, and which one is best suited to your needs.

Pin Style Moisture Meters-

• Generally provide the most accurate readings, and are the most commonly used by woodworkers.
• Moisture content is read by inserting at least two pins into the wood.
• Pins must be inserted deeply enough to reach the center of the wood for accurate readings.
• Pins will damage wood by leaving holes in areas where the probes are inserted.

Pinless Style Moisture Meters -

• Generally used for providing accurate readings on lumber less than 1" thick. Models for thicker lumber are available, but are typically inaccurate unless more expensive models are used. These meters are most commonly used by commercial operations.
• Moisture content is read by placing a flat metal plate against the wood, which requires that the wood be flat for adequate contact to be created between the metal and wood surfaces.
• Does not damage wood, as no probes must be inserted.

We highly recommend the use of pin style meters for most wood turners, as they are more affordable and work well for wood which is not flat (such as rough turnings). Pinless meters are more suited to cabinetmakers, or persons working primarily with flat stock lumber.

Keep in mind to always purchase a good quality product. Make sure to purchase a meter which allows for temperature and species corrections. More expensive meters will allow this to be done within the meter's controls. Midrange versions will include documentation with readable charts to allow for these corrections. Cheap meters do not allow for corrections and should be avoided. Another feature to look for with pin style meters is the ability to change out the meter's probes. Probes will tend to break over time. Being able to replace broken probes, or insert longer probes for thicker lumber will be very useful.

Finally, understand that most moisture meters are only accurate below about 30% moisture content. Freshly cut wood will usually be well above this level, so meter readings will not be accurate until the wood has been allowed to begin the drying process over the course of a few weeks or months (depending upon thickness).