"AHilton" wrote in message
...
{SNIP}
Your idea should work but as others have noted, you REALLY need to know
where it is (location and depth) or else you're going to have it flying
around the shop fairly quickly.

I wonder if it would fly out or immediately stick to the tool.

You'll also need to have a maximum of about
3/16" of wood covering each one in the finished product, depending on wood
specie, size of the magnet and how much force you want the two magnets to
exert together. Most woods are far more dense than human fingers or hands
but maybe not many heads g (referencing the oft-demonstrated trick of
putting these magnets on either side of a finger or hand and having them
"stick") and it doesn't take much wood to degrade the performance of these
really powerful magnets.

I don't think the wood will make much difference in the force between the
magnets. It is a function of the separation and magnetic permeability of
the material between them. I just tried a little experiment with some
3/8" dia. 0.2"thk. rare earth magnets (this size can already be tough to
separate). I put them on either side of my finger and they stayed in place.
I then tried it with a similar thickness of wood and noticed no difference.
I also tried how close to the table one magnet has to be to get the other to
jump up to it and noticed no difference with nothing, finger or wood. Just
to put some numbers to this, the magnets would jump together when separate
by about an inch with half of that space occuppied by wood. These might be
larger than he is willing to embed.

Martin

Martin