Needed a better magnetic bar than those sold for toolboxes, I had one but my small tools (pics and tweezers) would barely stick because they use ceramic magnets which are not all that strong. They work fine with large tools like wrenches but not the smaller tools with less ferrous mass.
So I had a bunch of neodymium magnets and decided to make my own. The magnets I used are 9.45mm diameter and 3.14mm thick, that equates to 1/8" thick and 3/8" diameter if you are looking for them in U.S. like ebay. Each bar holds 11 magnets
The bar is 195mm long x 15mm wide x 4mm thick.
I glues the magnets into the back with gap filling super glue (Hot Stuff Super T to be precise). The face of the bar has no magnets showing as I think this looks best. There are only a few layers between the magnet and the tool so most of the strength is still there. '
If you use the same thickness magnets I did then they will be flush with the back. I did this so I can stick the bar directly to my desktop file cabinet and it sticks 'very' well, no worries about it slipping or falling off. I think you could hang a 10lb weight on it and it would not slide off.
I used ABS, 3 bottom layers, 6 top layers and 4 perimeters.