I have 2 sets of drain/chimney rods, ages around 40 and 80 years (I bought one set then inherited dad's). I discovered when trying to extend one set that they have slightly different threads.
Trying to clear a blockage recently the "corkscrew" attachment came off. A Home Serve plumber jetted the blockage so the lost attachment is somewhere further along the system. I've bought a replacement but it does not match the thread on either set of rods.
Does anyone know the details of the 3 thread sizes?