I just had someone PM me about beefing up their shed security on a 4x3 window.
I thought I'd share my reply and open it up to comments and suggestions from others
When I did a shop door, I just used 1" box welded onto a frame made of more 1" box (my mate makes the chairs you see in restaurants and pubs so I had good access to it). As the shop owner wasn't allowed a permanent fixture, I welded 4 eye bolts to it and the put 3/4" L shaped bolts through the frame and into the brick work by about 6". The security railing was lifted onto the L bolts after they were inserted into the 4 holes. He then put 2 good padlocks onto two of the bolts (which were of course through the eye bolts). A 4x4 tried to pull the grill off...unsuccessfully.
I did suggest putting round bar in the box with bearings on either end so it couldn't be sawed or ground but weight was an issue as it couldn't be made permanent.
For a shed, most people (on site, etc) put concrete reinforcing mesh over the windows. Its put on the window and then flat steel either welded over the edges to bolt through the shed with( coach bolts with the heads on the outside) or just bolted on trapping the mesh beneath it.
Remember, if someone wants to get in they will. Most security is put up as a deterrent to opportunists.
I thought I'd share my reply and open it up to comments and suggestions from others
When I did a shop door, I just used 1" box welded onto a frame made of more 1" box (my mate makes the chairs you see in restaurants and pubs so I had good access to it). As the shop owner wasn't allowed a permanent fixture, I welded 4 eye bolts to it and the put 3/4" L shaped bolts through the frame and into the brick work by about 6". The security railing was lifted onto the L bolts after they were inserted into the 4 holes. He then put 2 good padlocks onto two of the bolts (which were of course through the eye bolts). A 4x4 tried to pull the grill off...unsuccessfully.
I did suggest putting round bar in the box with bearings on either end so it couldn't be sawed or ground but weight was an issue as it couldn't be made permanent.
For a shed, most people (on site, etc) put concrete reinforcing mesh over the windows. Its put on the window and then flat steel either welded over the edges to bolt through the shed with( coach bolts with the heads on the outside) or just bolted on trapping the mesh beneath it.
Remember, if someone wants to get in they will. Most security is put up as a deterrent to opportunists.