Which would be better to cut off some rusted nuts and bolts on my truck--an angle grinder or a sawzall? I'm trying to remove the gas tank from a 1970 Land Rover. It's underneath and I need to reach inside a rear wheelwell. There's not much room in there. I have no idea what type of bolts they are. A 1/2" wrench fits on them.
I tend to prefer a angle grinder with a cutoff disk for cutting off old rusty bolts. It usually is faster and less trouble then a sawzall.
But there are exceptions. The angle grinder does produce a greater amount of sparks so you need to make sure of where they fly off to and what could be ignited by them.
The other thought is the sawzall bimetal blades are about 1 inch wide and can reach normally for 3-10 inches into narrower spaces, the issue being is blade flex must be watched and kept to minimum to prevent breaking.
If both tools fit in without issue then pick the one you would use the most.
The simple answer is
If you can get to the head of the bolt, use an angle grinder. You can grind the head of the bolt off and then just pound the rest of the bolt off. It can be very hard to get to some bolts even with a small 4.5 inch angle grinder.
If you can get to shaft of the bolt before the nut, use a reciprocating saw (commonly called a sawzall). It is much safer and faster.
That's likely a 5/16" bolt. You might be able to shear the bolt by tightening it. That might be the easiest way of all.