Mitre saws are perfect for making angled cuts. It can cut through 115 millimetres of metal and weighs 19 kg, so it's nothing you want to carry around too much.
From Alan Wadkins
Makita LC1230 305mm TCT Cut-Off Saw 240v
HSS Toolshop
Makita LC1230 305mm TCT Cut-Off Saw (110V & 240V) - 240V
ITS
Makita LC1230 TCT Cut-Off Saw (Metal Cutting)