@lak Out of curiosity is there anything inside your 400lb 17th-century oak chest?
It's a cupboard chest, so rather than a hinged lid it has two doors on the front, there is a vertical divider up the middle and a shelf on each side. One side has an Ayre C5xe on the shelf, with turntable tools underneath. The other side is full of rather disreputable LPs that would not fit on my shelves (the kind one gathers from relatives and don't like to throw out, Great Western Movie Themes, Greatest Hits of 1968, Soundtrack from Dr Zhivago - that kind of thing). Certainly adds a lot of weight. I also have a large block of wood under the chest in the centre, so that it supports the bottom where the central divider is. I'm not going to make any changes to it that would damage its worth as an antique, and I don't want to know what it's worth! I had some canny grandparents that bought up all sorts of antiques in the 1950's when the exorbitant death duties of the Attlee government meant many large houses were sold up to pay the duties when the owner died. That was the intention of a deliberate policy aimed at redistribution of wealth. My grandfather, most of his life a fitter for the Crewe railway works, had a little cash from his football career, so he bought up antiques. I can't complain!