Hello all. I'm looking for some help to a what is probably a very simple problem but that is causing me some problems. I need to hinge a door formed from 40mm box but where the hinge mechanism is completely hidden from the 'front'. The two faces must meet perfectly flush when closed so don't think something such as a piano hinge will work. I may not have explained it very well so I hope the picture might help.looking forward to the very simple solution!