I went to the local "Travelling Wood Show" yesterday. (Yes, I confessed and have been granted absolution!) What caught my eye were sets of magnetic holdowns for featherboards. They sure looked simple, but I cannot figure out how they work. There were two sizes, the smaller used 3/4'" rare earth magnets and the larger used 1" magnets. The body was either aluminum or potmetal, a bit larger than the diameter of the magnet, and there was a twist knob on top that obviously operated SOMETHING internally, I assume another magnet.
How DO they operate, and does someone have a plan for them? These were being sold for about $30.00/pair for the little ones, and i know that the magnets are only about $1.25 each.
Any ideas? Duffy