Another small project completed a while back. We happened to visit Ikea near Vancouver - we don't have one locally - and I picked up three of these lights. Two black for the shop and one for my wife - she liked the gaudy version
I often use wood (in this case birch ply - I have lots of scraps) because it's easy to machine with my woodworking tools. In this case it works as well or better than metal so that's what I used.
This one has 4 1/2 in. rare earth magnets imbedded into the base.
This one has 3 1/2 in. magnets imbedded into the base. I drilled a slightly undersized hole and pressed them in with the vise - so far no problems with them coming out. This light is for my small mill and grips the metal plate on the wall very well. The taig mill does not have a lot of steel available so this was my option.
This was a very short project but the two lights work very well and are easily portable. If there is no steel machinery within reach I can always use a small plate of steel to place them in other areas of the shop.