George,
In Melbourne it's easy; I just go to SC Keable & Co, who have been selling nuts and bolts for a hundred years in the city. Their range is astronomical and their prices good, but count on spending half an hour standing around until you are served.....
But you can also go to a number of francised stores which are right around the country. Coventry Fasteners and Costless Bolts would likely have outlets in Hobart, certainly the former. Their range is huge also. Failing that, try any of the motor parts outlets as they have a huge range for the huge variety of cars in Australia.
The imported Umbrako Allen studs are wonderful, and if you really like 'em you can chrome 'em!
Cheers,
Hugh