Hi bartles-here is a link for wire rope. You didn't say the size you need but I think your drum size of 33mm(less than 1.5") is probably to small for wire rope. In my experience on small drums the wire rope is too stiff and when you get slack in the rope the wire unwinds from the drum and becomes a tangled mess. If you can find a 7x19or20 that could work but I really have not had good results with it. Good Luck
http://www.mcmaster.com/#standard-wire-rope/=pozvzi
Someone else on here may know of a more flexible wire. If you can figure the dia. that you need then maybe go a bit smaller that might help.