I started work in a machine shop here in the UK .All our machinery was run by belts. The power came from a twenty horse ,3phase electric motor . The belts did hurt when they came off gave you a good slap usually but we had a four spindle production drill where the belts ran horizontally , now they would cut you up if the wire claw fastener caught you in the face .
As the youngest apprentice ,15yo as I was , it was my job to wax the belts . I still have a bench top mill and a flat belt lathe