At dinner that night my dad explained where it came from. My grandfather bought up a cobbler's shop with all of its equipment and moved it to the local town to set up an aunt's fiance in business as 'Hop A Long Boot Repairs'. This would be the early 1950's. (52 or 53, right when cobbling was disappearing as a trade).
My dad was sent in as a lad to help get the business established (as his wages didn't cost much I think) and to learn the trade.
The Model T magnet was included in the equipment bought as an important tool. When the tacks were spilled or dropped on the floor then a wave with the magnet meant none were lost and all were recovered without wasted money in unused tacks
The business failed (much to dad's relief - he hated the work) and the romance flagged and various tools and rivets and tacks and bits and bobs found thier way into dad's keeping, including that cost saving Model T magnet.
The said magnet along with one of the sewing awls: