what I used to do was buy the metric brass pots slightly smaller and re thread them unf and screw them on to the imperial pyro@Hood don't know if you know this but there's a chart on the net somewhere that tells you what metric pots, seals & glands fit the old imperial stuff, I had to do a lot in a school once, spent 4 weeks re routing supplies
worked a treat
doing literlay hundreds of them over the years I only ever cocked one end up
when the cables were made off you had to identify and sleeve the cores and test them for shorts. nowadays you use a test meter in them days you were given a bell and a battery with leads to test. it rang when you identified the cores .that where the saying comes from bell it out 
ive seen cable cut back sleeved and a blob of silicone over the ends in to stuffing gland it would probably last for donkeys years if it wasn't disturbedWe had one sparks use a stuffing gland on an end once, I don't know how long it lasted
