Lignomat Ligno-Scanner (SD)

You can't guess, predict, or feel how much moisture is in wood, and you certainly can't rely on a moisture content reading that was taken weeks or months before at a lumber yard. The only way to accurately tell how much moisture is in the lumber you're getting ready to use in your workshop, is with a moisture meter. While it might seem like a lot of money to spend up-front, a good moisture meter will last for decades, and save you a lot of frustration, and possibly some embarrassment. Who hasn't make something that moved in ways we didn't intend after it was assembled?

There are two styles of moisture meters: pin and pinless. Both produce reliable results. The major difference between the two is that a pin meter will leave two small pin holes in your stock - not a problem if you can take readings where the holes won't show, or if you take reading before you mill the lumber. I much prefer a pinless meter. I take initial readings just before I mill my lumber, and then let the lumber stabilize in the shop for a week or two. I then take another set of reading before I do any final milling. But at this stage the lumber is about 1/8" oversized, and I'm not keen on making holes in any of it. Besides, I'm not always certain the pins are at the right depth, and I have a tendency to sink them deeper than they need to be. With a pinless meter I can take readings much faster than with a pin meter. So, for me, a pinless meter is the way to go.

Scanner, case, and instruction materials

Operates on a 9V battery (included)

The Lignomat Ligno-Scanner (SD) is a dual depth, pinless, capacitance-type meter. You can set it to measure to depths of either 1/4" (on thin stock and veneers) or 3/4". Essentially, the meter scans the wood, and produces a moisture reading that's the average of the area between the top of the wood and the maximum depth of penetration (either 1/4" or 3/4"). The meter does this by sending an electromagnetic (radio-frequency) wave through the wood. Electronic circuitry in the meter enable you to compensate for the different specific gravity of wood species. A 'species' button on the meter allows you to quickly select the correct specific gravity for the wood species you are measuring.

At only 8 ounces, and about the size of a cell phone, you can comfortably carry the Lignomat SD in an apron pocket, or on your belt, with the included vinyl carry case. The keypad is well laid out, and the keys easy to decipher. Under some lighting conditions I found the screen a tad difficult to read. Using the scanner is very easy. Pressing the 'Read' button turns the unit on, and starts the scanning process. Pressing the 'up' or 'down' arrow keys switches from shallow (1/4") to deep (3/4") scanning mode. In order to obtain the most accurate readings you should use the right depth scanning mode. For wood that is 1/2" thick or thinner, use the shallow mode. For wood 1/2" to about 2" thick, use the deep mode. Press the scanner firmly onto the wood surface, and take readings at several locations. You want to ensure that all of the scanning area on the bottom of the unit is on the wood your scanning. You won't get accurate readings if you try to scan the edges or ends of boards.

As you well know, specific gravity (relative density) varies between wood species. This difference in density has to be accounted for when determining the moisture content of the wood. The Lignomat SD uses programmable electronic circuitry that enables you to enter the specific gravity of the wood you are scanning; the Lignomat then automatically makes a correction to the moisture content reading based on the specific gravity level. You need to change the specific gravity unit on the meter for each species; however, doing so is very fast and easy, as Lignomat includes a laminated species card with the relevant levels for 71 species of wood, both domestic and exotic. After a short while you'll remember the levels for the woods you most frequently use.

I've been using the Lignomat SD regularly for over a month now, and I've very pleased with the unit. I really only have two minor complaints. The user instruction sheet refers to the ability of switching from inches to millimeters for measuring depth. I couldn't get this feature to work. For changing the measuring depth he instructions also tell you to press the 'Set' key until the ':' sign appears on the left of the screen. This didn't work either. Simply pressing the up and down arrow keys changes the depth setting. I also found that, no matter how steady I held the unit, every time I pressed the 'Hold' button, the display reading would shift a percent or two, sometimes up, sometimes down. Fortunately I don't use the hold feature.

Regardless of these minor issues, the Lignomat SD is a stellar performer that any woodworker will be pleased to own and use.

Reviewed January 2011