For rivets and bolt heads I simply slice up hex rod and round in various diameters TBH I can never see the hex shape below 0.5mm which is as small as I go. I normally sit at the coffee table when I'm not actually building and cut up a length and simply store them in small labelled pots for future use. I estimate a 300mm length will give you a good (useable) 400-500 bolts/nuts!
The most useful tool I've found is an adjustable (2 - 4.5mm in 0.5 increments) leather wheel punch, like this:
http://www.machinemart.co.uk/shop/product/details/cht489-revolving-leather-punch?da=1&TC=SRC-leather punch
Looking forward to more great scratching
ATB
Dick






















