Less than a week ago I ordered some lockers form this firm Linky I have to say the quality, design, price and service are absolutely brilliant. I would throughly recommend them.
So gushing over. Heres how I did it. From the inside I marked where I wanted the center of the door. As I wanted the door flush with the floor inside but need to make the initial cuts from the outside, I drilled a small pilot hole 2" above the floor in the center where I wanted the door to fit. It was then simple to work from this datum to mark out the hole to be cut. The door is 20" x 24" (WxH) and there will be another on the other side. The reason for not drilling at the floor level is because the body of the drill will force the drill bit to aim downwards ending up below the floor line outside.
Outer skin removed to reveal yet more stainless steel
I am now using a 9" angle grinder with a thin cutting disk for stainless to cut all the holes in the body. It is quicker and neater than a jig saw.
Hole now cut easily with the 9" grinder
As the door is going to be glued in place so its necessary to rough up the surfaces to be glued. A light sanding with a small grinder is all thats needed, then I clean the surfaces with meths just make sure there is no dust or oily surfaces left.
Finally the very nice door fitted