My tutor mentioned that it would be useful to have some steel rods to use with the swage block, as all of the school ones in the small sizes had disappeared. So - I went to 4D Modelshop and bought some rods of mild steel in different gauges. They told me there I could cut them into lengths with a hacksaw. It didn't even scratch the surface!
I am stubborn, so I asked around, and was told that I should use bolt cutters. Well, every girl needs a pair of bolt cutters, so off I went to Screw-Fix to buy some (yes, I got some strange looks but they were actually very helpful in there).
Anyway, after much effort, and my son's help with the thicker rods (we had to use both our weights to cut through them. They were only cheap bolt cutters...) - I now have 6 sets of lovely handmade mandrels. (I rounded off the sharp edges with a bench grinder).
They fit nicely into the swage block, and are really useful for making jump rings as well! I will offer the 5 remaining sets to the girls on my course.
This last image shows a swage block, which is used to make tube out of sheet metal. You can also make half tubes and other curves. The other side of the block has much larger grooves, and the idea is you take a strip of metal, place it in the groove, place a mandrel over the top and hammer gently. The metal will take on the curve in the groove.
You then repeat the process with smaller and smaller grooves, until the metal strip has curved over itself into a tube.