Moisture meters should be a tool that every woodworker has in their shop. They are such a simple machine that can make a huge impact as to whether or not your project is a success that can hang on your wall or a failure that will require rework or perhaps even being scrapped.
If you have ever built something out of wood and found that after a few months the piece had started to develop cracks or begun to break apart at joins, odds are the wood you used was not at the proper moisture content levels. This is a perfect example of how a wood moisture meter
could have helped you by telling you that the wood you were preparing to use wasn’t ready. If you are interested in more details on why a moisture meter is an important tool to have in your woodshop, take a look at my article here.
There are many moisture meters on the market that come with a wide variety of features. These features translate into a wide range of prices as well. Of the meters I’ve used, the General Tools MMD7NP is the one that I recommend most to general woodworkers. If you need very precise measurements, then other more expensive units will be better (usually a few hundred dollars), but I feel like the MMD7NP will work for the majority of woodworkers.
The nice thing about this particular moisture meter is the fact that you aren’t limited to using it only with wood. It’s a tool that will come in handy around the house too. In fact, last winter I had a small leak in my wall due to a pipe freeze and this helped me check around the drywall in my bedrooms to find what area had the most moisture present.
If you’ve researched moisture meters in the past, you know that they come in two forms – pins and pinless. Both work the same by sending small electrical currents thru the material you are testing to see how quickly the current moves between two points. The great thing about pinless models is that they don’t damage the material you are testing. This is another reason I like the MMD7NP so much. I can test material as much as I want and don’t have to worry about patching up the damage caused by pins poking into the material.
The other thing that comes in handy with this meter is the fact that it can measure moisture levels up to ¾ of an inch deep. Sure, other models will measure deeper, but you are going to pay significantly more money for this feature. A depth of 3/4” should be enough for most users.
What I like
The number one thing that I like about this unit is that it is easy to use. I can have a reading in just a few seconds. I just turn it on, hold it against whatever I’m measuring (99% of the time this is wood) and it gives me the moisture content. I love that I don’t have to fumble through multiple screens to adjust settings if I just want a quick reading. It just works. That’s a huge positive for me.
The other thing I like about this meter is its size. It small but also very easy to handle. It fits in my hand perfectly, but I also stick it in the pocket of my apron if I’m going to be using it several time and it doesn’t get in the way or pull my apron down.
I’ve had great success with its accuracy. My projects don’t require my readings to be scientifically precise, but this unit gets me close enough. Using pin meters will get you a more accurate reading, but the downside is that they are going to damage the material you are testing.
Just about any device that you buy is going to have a few negatives. The MMD7NP is no different.
I haven’t personally experienced any issues, but there are a handful of people online that have reported the unit not working after a few months. Overall, from what I’ve seen, it doesn’t appear to be a problem that occurs often. Should you experience a malfunction, Dr. Meter does back the moisture meter with a 1 year warranty in the event of a failure. I’ve never had to use their customer support before, but I did a quick search online and found favorable experiences.
The only real negative that I can find out this unit, and it’s really being picky, is the screen. Not only is the screen a bright neon green, but you can’t look at the screen at too much of an angle or the numbers become illegible. I really hadn’t notice the issue until I was taking photos to put in this review. It certainly has no impact on use of the machine.
Hopefully this review has helped provide some insight on the MMD7NP. It’s a great little unit that should be plenty for the majority of weekend woodworkers.