cwmorris
hi You have to make a soldered joint between the lead and normally copper pipe which can then be used to join to any other material eg plastic etc.Any older plumber can do this it is a specilized art not much used these days. In UK this type of joint is not allowed on water pipes and a joint known as a LEADLOK is used but I dont think you can get these in large sizes.If the lead is in good codition you may be able to fit a universal plastic waste fitting on it, this has a nut and a compresion rubber ring.hope this helps. Colin.
