I agree but there is also an inner rotation at the bottom pivoted around the top hinge. The big difference of course is that at the top the rotation is pulling the door away from the jamb and at the bottom it is pushing it into it. The distortion effect on the two hinge pieces should be equal but the screws on the bottom hinge plate are almost unneccesary.Originally Posted by friscofrankie
Older Thai houses used to use doors that bi-folded upon themselves to open the entire front of the house. The outward stresses on the top hinges must have been considerably greater than on a more conventional 200*80 door and 4 or more hinges would have been essential - and I'm sure that hinges with bearings where far less common then than now.
For a normal door I expect that two hinges would be adequate but I suspect that there is an element of 'it's always been done this way and so why change'. Anyway labour is cheap and hinges aren't exactly costing the earth so I'm fitting four hinges too.![]()