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Nail detection in used lumber

19K views 28 replies 18 participants last post by  RiovistaAndy  
#1 ·
I am looking for a good magnet for detecting metal in used lumber. I know this has been discussed before but I can’t locate the thread.

Thanks.

Jon
 
#2 ·
I'd think any of the small high powered magnets would work. I'd likely wrap it in something so it slides easily and has some sort of grip. You want to feel it being attracted to metal. I think I'd try wrapping it in low friction tape and leaving a couple of extra inches taped together like a tab. However, I think what will inevitably find the tiny metal bits will be your jointer or planer.
 
#4 ·
#8 ·
I have the Little Wizard... and it misses nails/screws, I wouldn't recommend it. I replaced it with the harbor freight wand type, which works great, and has never failed, although I have never used it on logs, but works great on pallet wood and reclaimed 2" construction/demo lumber.
https://www.harborfreight.com/9-volt-metal-detector-wand-94138.html
 
#6 ·
Stud detectors are different than metal detectors, Jon. I don't think I'd trust a stud detector to thoroughly scan a piece of lumber; if the nail is for arguments sake a finish nail, and it's perpendicular to the wood's surface, there's an excellent chance it won't be detected if you don't pass directly over it (with the stud detector). Much better odds with the metal detector
https://www.leevalley.com/en-ca/shop/tools/workshop/45125-metal-detector
Note that it detects all metals, not just ferrous.
 
#7 ·
#14 ·
Truth. I got some 2x4s from HomeDespot and was cutting them on my 10" SCMS. About half way through my cuts started coming out terrible - really ragged. I stopped and looked at the blade. It had a twisted tooth sticking about 1/4" to one side. Went back through the cutoffs and sure enough there was a screw I'd sliced through and didn't even notice. This was with brand new, just purchased 2x4s. Fortunately, the blade was an older one that I expected to replace at some point but it is still disheartening to have to trash a blade because of someone else's negligence.

This is why I always carefully inspect any wood I'm cutting. And, why I don't bother with recycled wood. Losing a blade sure cancels out any savings. Getting injured, even more so.
 
#15 ·
To find nails you need a metal detector of some sort and not a magnet or a stud finder. A magnet won't find them unless maybe you are holding the board upside down and the nail is just below the surface. A stud detector is too small to do any good. A metal detector is meant to find any kind of metal. A problem that you will run into is that the nail is below the surface and no way to get it out. For me, I drive the nail deeper so that the planer doesn't hit it. As far as sawing the lumber, a table saw will go right through a small nail without any noticeable damage to a blade. A bandsaw blade on the other hand will be ruined.
 
#16 ·
I've got the Garrett Super Scanner V...

Not all "super scanners" are Garrett's...be careful out there...
 
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#18 ·
If I recall, the one I bought was a Garrett from a reputable supplier.

Left the battery in for too long and the contacts corroded away......
 
#20 ·
I tried my Zircon stud finder on it`s metal scan setting to see what it would do. It couldn`t fully detect a 1.5 inch finishing nail through five eighths plywood. Some of the lights lit up but not all. It had no trouble when I laid the nail on the surface so I think it would be good with a nail that was just under the surface.
 
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#24 ·
#28 · (Edited)
A very inexpensive option for you would be disassembling a hard drive from an old unused computer. There are some very strong rare earth magnets inside of hard drives, and if you have an old one laying around collecting dust, you can have a free magnet, some even have 2. Of course it would only detect ferrous metals, but then again, most (not all) nonferrous metals are soft enough that a woodworking saw blade won't get harmed. The reason for using a strong magnet like a rare earth magnet, is because it can become attracted to metal buried in the wood that you can't see, just like a metal detector.