Tip for those relays is simply to clean the contacts, using a contact file ( or the smallest flat file in a set of regular needle files) to get the surfaces mostly flat. Nothing too rough, just take the bumps off once every few years and the contacts will survive. The broken insulator is Bakelite, available from most industrial material suppliers of plastics, so just get a small offcut of the right dimensions and cut with metalworking saws, avoiding the dust.
LED lights for the lathe are available, but the original lights are still available from the larger industrial suppliers, or they have LED retrofit kits. LED lighting for the work area is good, buy a good quality waterproof one ( and 2 spare ones, they will be broken sometime or the other) with a separate 12V transformer, and a decent mount. A smaller one on a magnetic clamp will also be invaluable.