I've noticed over the years the metric rods coming with a lot of ARF's are a harder metal(more brittle) these rods a lot of times crack(stress) in a zbend. Had some break during the zbend process and most crack if pushed as far as the old 2/56 or 4/40 wire. The wire rods I use from the local HS is a lot softer and take the z bend vary well. I no longer use the metric Arf's rods in a zbend.