CRITICAL FLAW ALERT!
This meter exhibits a critical flaw—namely its inability to provide results below 8% moisture content, even though the manual states it gives readings to 5.5% moisture content. This flaw renders the meter essentially unusable for a number of common applications, including for flooring installations and furniture making. We deducted one star from our overall rating to reflect this critical flaw.
The General MM70D is a pin-style wood moisture meter that offers a cabled pin probe accessory with the option of also adding a roller-type probe. The meter is reasonably simple-to-use and offers an easy-to-read digital readout.
However, do not rely upon the MM70D for measuring wood with low MC levels below about 8% MC, even though the manual states that it is able to take measurements as low as 5.5% MC.
It is designed for both wood and other building materials. Adjustments are possible for eight different groups of wood species using the species calibration table included in the manual.
The General MM70D is not recommended because we found it to be ill-suited for measuring moisture at low moisture content (MC).
This means it is not very useful for flooring installations, furniture making, and other common applications. Better options exist in this price range.
Pros
- Simple-to-use with large, easy-to-read LED display
- Features data hold button, also records min/max and average values
- Built-in calibration adjustment
Cons
- Unable to take readings below about 8% MC
- Readings affected significantly by surface moisture and meter temperature
- Casing is not high quality and is subject to breakage
General MM70D Moisture Meter Push Probe
This is a pin-style wood moisture meter that features a cabled pin probe accessory. We tested it.
Objective Evaluation – Overall Score 3.6 out of 5.0
Accuracy – 4.0 out of 5.0
This meter scored reasonably well for accuracy when compared to ASTM D4442 oven dry standards. In our testing, this meter was unable to obtain readings below about 8% MC even though the manual states that it can readings to 5.5% MC.
Learn about our accuracy test procedures
Surface Moisture – 1.0 out of 5.0
Surface moisture caused this meter to post readings about 13% higher than the baseline. These surface moisture results indicate that operating this meter in high humidity environments where condensation may form on the surface could lead to questionable readings.
Learn about our surface moisture test procedures
Meter Temperature – 3.0 out of 5.0
Meter temperature had a significant effect on this meter’s MC readings. A low-temperature reading of 34.8° F in the presence of high MC lowered the reading by almost 2% compared to the room temperature reading.
A high meter temperature of 110° F in the presence of low MC increased the reading by 2% compared to the room temperature reading. In the presence of high MC, the reading decreased by about 0.5%.
Learn about our meter temperature test procedures
Wood Temperature – 4.0 out of 5.0
Wood temperature affected this meter’s readings.
A low wood temperature of 33.6° F in the presence of either low or high MC showed only a little appreciable change in the reading when compared to the room temperature reading.
A high wood temperature of 110° F in the presence of low MC showed about a 1% increase in the reading when compared to the room temperature reading. In the presence of high MC, the reading increased by about 3%.
Learn about our wood temperature test procedures
Reading Repeatability – 5.0 out of 5.0
The readings of this meter were mostly repeatable, showing very little tendency to vary.
Learn about our repeatability testing procedures
Drift – 4.0 out of 5.0
Readings for this meter showed a small tendency to drift, with readings that were about 0.2% MC lower after three seconds.
Cable Interference – N/A
The General MM70D offers cabled accessories that were evaluated in a separate review.
Learn about our cable interference and drift testing procedures
Subjective Evaluation – Overall Score 3.2 out of 5.0
Learn about our subjective testing procedures
Ease of Use – 3.5 out of 5.0
This meter is relatively simple to operate. Four buttons mean it is necessary to consult the manual in order to understand all the available options. Documentation provided in the manual is adequate.
Quality – 2.3 out of 5.0
This meter is not exactly intended for the budget-conscious individual, given a base price of over $200. However, it has a lower quality appearance, and we found the meter’s casing to be subject to breakage during our testing. Using the supplied pins can be frustrating because they are subject to bending or breaking too.
Comfort – 3.5 out of 5.0
This meter has an ergonomic design that is comfortable to hold, the display is easy-to-read and the four control buttons are relatively easy to use. No carrying case is provided.
Versatility – 2.0 out of 5.0
This is a pin-style meter only that is not capable of adjusting for species. Unless using the push probe accessory, data must be viewed upside down while the meter’s pins are inserted into the wood sample. Using the HOLD function can address this issue.
Range – 3.7 out of 5.0
Measures moisture content from 5.5% to 50%, at least in theory. In practice, our tests indicated that no readings can be obtained reliably below about 8% MC.
Features – 3.5 out of 5.0
Readings precise to the nearest 0.1%. Low battery indicator. Offers a calibration adjustment and a HOLD function for use in tight spaces where the display cannot be easily viewed. No meter re-calibration offered by the manufacturer.
Customer Service – 4.0 out of 5.0
General offers free replacement if anything goes wrong in the first year. No service center is available for repairs, nor does General offer any calibration services for its meters. Response to telephone inquiries is fast and friendly.
Our review is based on Moisture Meter Experts independent evaluation of the meter, which was purchased by Moisture Meter Experts or provided free of charge by the manufacturer. By purchasing this meter through the links above, Moisture Meter Experts may be compensated either by your purchase directly from Moisture Meter Experts or from commissions from an affiliate. View our Review Procedures section to learn more about our proprietary evaluation procedure and expertise in the field of moisture meters.