If you always buy your timber from the local hardware or wood supplier then read no further, this article is not for you. However, if like me you are a little OCD and your internal self dies a little every time you see a nice piece of wood go to waste then read on. You will thank me later.
In every recycling woodworkers life there comes a time when they will encounter a piece of ironmongery in the most unfortunate of places. The latest episode for me (and the one which convinced me to buy a metal detector) was when I was milling the edges of my woodworking bench top. I had set up my brand new TS 55 to square the edge of one of the slabs, 50x400x2000 approx. and noticed some sparks about half way along the edge. When I checked I noticed a lovely shiny wood screw head flush with the edge and I just ruined a brand new festool blade. Ouch!
After some research I settled on the one pictured here.I picked it up for about $24 with free shipping from ebay. My criteria were that it had to be portable, have a audible and visual indication, have good sensitivity to both ferrous and non-ferrous metals and easy to use. There are a number of different models varying in price and specifications but this seemed to be the best value for money and satisfied al of my criteria. When you buy on ebay you often never know whether what you are getting will do the job but after getting it an testing it out I am not disappointed.
It has two positions, one for visual and vibration indicator and the other for audible, visual and vibration. It will pick up any ferrous or non-ferrous metals and will pick up a pin at 30mm which is more than sufficient to detect nails or screws inside of your wood.
A couple of examples. I wanted a piece of ply and there are some scraps of old 18mm marine ply knocking around. One piece looked rather ratty but it looked like I could cut out a piece that would be suitable. I grabbed the metal detector and swept the ply only to find several broken screws embeded in the ply. I grabbed a pencil and circled each of the screws as the detector picked them up and found that I was still able to cut around them easily to get the size I was looking for. I then scrapped the rest. The second example was when I was looking for a slab of jarrah for a small table top bench I was building. I found a piece that would have been perfect so I swept it with my metal detector only to find that there were several old rusty wood screws embedded into the side of the slab. I was unable to remove them since they had rusted in place and I had no idea how deep they went. I abandoned that piece and used two other pieces which I jointed and glued into s single slab. I will probably use a hole saw to extract the screws and plug the holes with dowels and use it for something else.
I have a lot of reclaimed wood and this metal detector will hopefully save many saw blades, jointer heads, thicknesser blades et al.