I have a 40's WFL tom mount like the one in the photo here.
The round cogged pieces have two small metal fingers that fit into matching holes on the round cogged pieces. Sorry, I don't have photos right now but I can get them up here soon. These metal fingers have worn off and the part doesn't work without them. I went to a machine shop and it is going to run me about $90 to 'refinger' the three parts. I could probably wait and buy a complete part on eBay for less than 1/2 that ($3.50 in 1939 is about $45 in today's dollars).
Does anyone here have some of these round parts for the tom mount?
The holder was made from 39-50 according to Rob Cooks book.