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CRITICAL FLAW ALERT!
This meter’s accuracy was fair between 10% and 17%. Accuracy was significantly lower below 10% and above 17% moisture content. Many readings below 10% were showing as zero, and readings above 17% leveled off. This flaw renders the meter unsuitable for flooring applications and furniture making. We deducted one star from our overall rating to reflect this critical flaw.
As with all pin meters, it can be very difficult to insert the pins far enough into hardwoods to obtain accurate readings. Attempting to do so often results in bent or broken pins. Also, short pins will not reach far enough towards the center of thicker slabs where higher moisture is found. According to the United States Department of Agriculture, boards should be read at a depth of one-fourth to one-fifth of its thickness.
The General MMD4E is a single function pin meter for wood and building materials. Its 3-button simplicity makes it easy to operate.
The stated moisture range is 5% to 50%. This meter has no species selection and has just one choice for all wood measurements. The manual says to come up with your own moisture curves for different species and ambient humidity.
Pros
- Large backlit display
- Simple 3-button operation
- Compact size
Cons
- Only one species setting
- No carrying case or soft pouch
- Pins break easily
- Not able to read wood below about 8% MC
Objective Evaluation – Overall Score 4.0 out of 5.0
Accuracy – 2.9 out of 5.0
The MMD4E had reasonable accuracy between 10% and 15% moisture content. Accuracy diminished above 15% MC.
Learn about our accuracy test procedures
Surface Moisture – 1.0 out of 5.0
Surface moisture increased the reading for the MMD4E by over 19%. Operating this meter in high humidity environments where condensation may form on the surface will produce very high readings.
Learn about our surface moisture test procedures
Meter Temperature Test – 4.0 out of 5.0
The MMD4E scored well when exposed to cold and warm temperatures. It read 1.3% low when cold and 3% high when warm.
Learn about our meter temperature test procedures
Wood Temperature – 5.0 out of 5.0
The General MMD4E performed very well on different wood temperatures. It read less than 1% high when measuring wood that was 110 degrees F.
Learn about our wood temperature test procedures
Reading Repeatability – 5.0 out of 5.0
This MMD4E performed very well on consecutive readings. Only a 0.3% variation among 5 different readings.
Learn about our repeatability testing procedures
Drift Test – 5.0 out of 5.0
Very little drift over 3 seconds for the MMD4E.
Cable Interference – N/A
No cable interference test for this meter since it was tested using built-in pins.
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
The General MMD4E meter scored reasonably well in this category with its simple operation and compact size. It contains a large backlit display but points were deducted because of the one wood setting and pins broke during testing. Points were also deducted since there is no lookup table to compensate for changes in the wood temperature. All pin meters are sensitive to wood temperature.
Quality – 3.0 out of 5.0
Meter case held up during our tests, but the pins tend to break. The pins are easily replaceable.
Comfort – 3.5 out of 5.0
This meter is small enough to fit in a pocket and has a large backlit display. There is no hard case or soft pouch included with the meter for transportability.
Versatility – 1.0 out of 5.0
The MMD4E did not do well in versatility. Pin only operation and inability to program individual species settings or groups decreased this rating.
Range – 5.0 out of 5.0
This meter’s measuring range for wood according to the manual is 5% to 50% which is good for all woodworking applications. However, our accuracy tests yielded no readings below 8%.
Features – 3.5 out of 5.0
The MMD4E is a pin-only compact meter and has a large bright display. It has visual and audible alarms for high moisture content. Calibration can be verified by the user.
Customer Service – 3.0 out of 5.0
This General MMD4E meter comes with a standard 1-year warranty. There is a service center located in the US, however, we didn’t receive an email response within 3 business days.
Warranty and repair information:
- 1-year standard warranty
- Service center located in the US
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.