As I am just a begginer on the lathe I am using whatever bits of steel I can get hold off .
I have found high tensile bolts are a good source of small round stock for some of the things I am doing.
Yesterday I called in at my local Russels farm machinery store as I wanted a piece of steel 150mm x 25mm dia to make a new longer key for the headstock chuck, just because for health reasons I can't get the purchase required to hold the bar stock. A 25mm bolt 200mm long was going to cost £33.00 in High tensile steel, so that was a no no.
Instead I opted for a 150mm long Pin that is used to join a tractor to a farm trailer for about £6.00. I dont think it is High Tensile steel but it turns very well.
I have found these retailers of large bolts etc are very helpful when you let them know what you are making.
Just thought I would pass this on in case the information was of any use to anyone.