MTFCA Forum

Consequently, the bottom part of the magneto coil assembly has a certain amount of spring to it, and may be attracted into actual contact with the brass plates over the magnets when the powerful current from the storage batteries is sent through the windings, thus giving greater magnetizing effect.
~ Murray Fahnestock

I've never seen any brass magnet plates. I've never even heard of them. Were they actually used at some point, or is this just a typo?

The article by him in the booklet "Electrical System" says brass screws.
Norm

Not seen brass plates but brass spools yes

Wouldn't work, must be a typo.

I just upgraded a 1917 transmission, to a 1920 with a starter, that had a double mag coil ring and brass spools to support the magnets.

Wheter this was original or just a use of available earlier parts is a total unknown for me.