Another thread made me think about anchoring a double skinned safe with a loose fire resisting lining. I don't like drilling out a hole in the base, as it is messy. Of course it can be done with one of the good quality hole saws that mount on a drill.

I saw one once which belonged to a blacksmith. It was on a wooden floor, so no anchoring was ever going to be very good. He had made 2 bands which wrapped around the safe, one at the front and one at the back. These had small "feet" bent out at the bottom, drilled and coachbolted through the floor. He then had a third piece of steel just in front of the safe, again coachbolted through the boards. Of course that prevented the safe from being slid out from the straps. It was actually very neatly done. I realise a baddie could have gone under the floor and unbolted the thing but it did stop anybody simply walking off with the unit.

The big problem is that you shouldn't weld to an old fire resisting safe as the heat generated will start to triger the sawdust and alum mixture. Equally if you have one which has asbestos between the skins, well who wants to drill asbestos?