Not sure if it's surprise to open from the key ? But last night my partner was out I was bored and I decided it would be cool if it opened on its own ,,,, I started by lubricantibg tge hinge with a ptfe spray I then spayed the struts with silicone. Next step was to add more tension to the springs, At the rear bed of the spring were the loop in the spring is I wedded the spring with a flat head aces driver to open up the gap between the spring and the mounting plate I then added 6 2p price in the gap Spacing the spring Adds tension It has worked everytime since I did this I was going to make spacers but the tension of the spring holds the 2ps in nice and its adjustable simply add or remove coins to get the opening speed you would like