Top 5 Differences between Pin and Pinless Moisture Meters

When looking for accurate wood moisture measurements, you’ll immediately run into two different styles of meters: pin and pinless. Which is the better addition to your tool belt? There are some basic differences that you should understand before you buy.

Pin vs. Pinless Moisture Meters

Too obvious? Maybe. But let’s point it out anyway. Pin-style meters usually have two metal pins that must physically penetrate the wood’s surface in order to take a moisture reading. Pinless meters use a sensor pad that works in contact with the wood surface but does not physically break or damage the surface to take a reading. Let’s look at why that matters.

Sensor Size vs. Pinpoint Accuracy

MMC220 Measuring Wood FlooringThe true difference rests in the underlying technology of each type of meter. Pin meters work on a resistance principle that measures the flow of electricity between two pin tips and measures the moisture content (MC) of that very tiny path. Keep in mind that pin meters only measure the MC at the point in the wood between the two pins. Multiple readings are always necessary to get an overview of the MC. Pinless moisture meters use a larger sensor pad and emit electromagnetic signals to measure the MC of wood. This provides the unique ability to quickly and accurately “scan” larger areas in each wood piece, providing instant MC readings. This technology can scan many board feet in seconds without the time-consuming effort of driving pins into the wood.

Holes vs. No Holes

As we’ve already mentioned, a pin meter will penetrate the wood’s surface to measure the MC. Therefore, each MC reading will make a pair of holes in the wood. For 2x4s or firewood, this might not be a problem. For wood flooring, fine furniture, cabinets or other fine woodworking projects, those holes become a series of blemishes in the surface of the wood. Pinless meters leave no damage to the surface.

Fixed-Depth Readings vs. Variable-Depth Readings

Pinless moisture meters generally operate at two standard reading depths: ¼” below the wood surface, and ¾” below the surface. For most woodworking projects, like wood flooring or cabinetry, these depths provide the necessary MC readings required. Because pin meters take readings between the two pins, they offer slightly more variability in reading depths. The MC reading will always be taken at the depth the pins are driven into the wood. (Of course, this also means that if the pins are not inserted properly, the MC reading may not be accurate.) Pins are generally replaceable and can be purchased in different lengths, or the meter itself can be attached to external hammer probes for deeper MC depth readings.

Breakage vs. Calibration

Because of the force necessary to insert a pin meter into the wood, the longer the pins, the greater the risk of breakage during use. If you don’t have replacement pins on hand, the meter becomes unusable.Calibration Block for Wood Meters Pinless meters are less prone to breakage during normal use, but must be properly calibrated (as both styles must) in order to provide accurate MC readings. Fortunately, a calibration check on most pinless meters can be quickly verified on the job site using a calibration verification block purchased directly from the manufacturer.

Naturally, the accuracy of both pin and pinless moisture meters depends on using them correctly according to the manufacturer’s instructions. Also, you must program the meter or use specific gravity (SG) adjustment tables for each wood species that you are measuring. Understanding the differences and the proper use of either pin or pinless meters ensures that you’ve got the MC readings necessary to get your wood project completed for a lifetime of use and enjoyment.

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Tony Morgan

Tony Morgan is a senior technician for Wagner Meters, where he serves on a team for product testing, development, and also customer service and training for moisture measurement products. Along with 19 years field experience for a number of electronics companies, Tony holds a B.A. in Management and his AAS in Electronics Technology.

12 Comments

  1. Dick McCarthy says:

    I recently purchased a Masterdraft pinless moisture meter model 057-4572-0 from Canadian Tire. I bought it to measure the moisture content of my firewood. I am not certain if Big Leaf Maple (Vancouver Island) is considered softwood, hardwood, or soft hardwood. More importantly I am not certain if this moisture meter can measure the moisture in firewood. Perhaps it is only designed for kiln dried dimensional lumber. I have been told that Wagner makes, or is the dealer for Mastercraft moisture meters so I hope you can answer my questions for me. When I checked Wagner on the internet, your name came up and this is the e-mail I was given. Can you help me. I certainly would appreciate it.
    Thanks kindly,
    Dick McCarthy

    • Ron Smith says:

      Thanks for writing, Dick. Wagner Meters does not manufacture Mastercraft moisture meters nor do we offer any meters that are designed for use with firewood. I’m sorry for any confusion. I’d suggest returning to the store you purchased the meter from or contacting the manufacturer directly for assistance.

  2. Jeremy says:

    Hello,
    If the wood has a surface coating can that affect the reading of the meter? For example painted wood or a lacquer coating. If yes then does that mean one should use a meter with pins?
    Thanks,
    Jeremy

    • Jason Spangler says:

      Jeremy:

      Thanks for the question. No, neither of the coatings you suggested here would have any impact on the readings obtained by our meters unless the coating contained aluminum oxide or any other metallic. In this case, there would potentially be variances in readings.

      Jason

  3. noda droper says:

    Question – We are preparing to re-paint wood clapboard house and want to make sure that the underlying moisture of wood is appropriate before painting.

    Pinless or 2-Pin Model: We would prefer a Pinless meter (fewer holes left in wood, more readings). Can we use a pinless wood moisture meter to assess readiness for paint, assuming that we are testing not raw wood, but wood that may have already been painted and scrapped, or primed?

    • Tony Morgan says:

      Yes, a pinless can be used to measure the painted wood on your house as long as you know what the wood species is for the clapboards. Paint should not significantly affect the moisture readings of a pinless meter. The only obstacle could be if there are too many layers of built-up paint over the underlying wood or there is metal content in the paint, lead-based paint is an example of this.

  4. Tim says:

    We’ve treated some roof timber with a preservative. Will this affect the readings of either type of meter?

    • Tony Morgan says:

      Tim,

      It depends on the type of treatment you used. If the treatment has no metal content in it, such as copper, there should not be a significant change in your readings. If the preservative is metal-based, there may be a rise of 4% or more in your readings. The best way to check the effects would be to take some readings of a non-treated section of the roof timber, treat the timber and, after a sufficient drying period, recheck the same section for any change in the readings. This would give you a baseline and correction factor for the treated timbers.

      Thanks,

      Tony

  5. Ramiro Rivera says:

    Would the pinless moisture meter be able to penetrate through stucco on houses? Typically stucco is 3/4″ to 1″ thick and contains lathe. I would be interested in figuring the moisture of the sheathing (typically plywood) behind the stucco/lathe AND then use a pin meter for specifics.

    • Tony Morgan says:

      Hello Ramiro,

      The BI2200 is designed to take relative readings for many products, including stucco, but there is a problem with your intended application. The problem with stucco is that it is normally troweled onto a wire mesh, and this mesh would most likely interfere with any readings you would be trying to get from the lathe underneath. The metal of the mesh will disrupt the electromagnetic signals of a Wagner moisture meter and the result would be inaccurate readings.

  6. vijay kumar Srivastava says:

    requirements of pin type moisture meter rate and catalouge

    • Tony Morgan says:

      Hi Vijay,

      I am not entirely sure what information you are seeking. Can you provide clarification?

      Thanks,

      Tony

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