Another option is to buy your steel from the stockists, get a 4.5 inch grinder, with one of those wafer thin steel cutting discs. They cost a quid each, and are brilliant ! Failing that, rent a chop saw from your local tool hire store for the weekend, and crack on. My local tool hire shop wants £25 all in, from 8am Saturday, until 8am Monday. You can have a few frothy bevies while you are doing it, get the misses to pop the barby on as well. Lovely.
