1, good hinge is the form of bearing, in general, there are 4 bearings in one.
Well, there are 2 hinge damping oil, if you put a horizontal hinge, hinge is not real, nor is it suddenly fell down, but slowly sliding down, the benefit is that your future is not closed, but not hard, the door hit the door.
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3, good hinge has brass and stainless steel. Brass hinge is generally yellow and better. This indicates that copper content is high, generally it can be made of 62 copper (probably copper content). The hinge is very good.
4, the difference of the page will be cut off, the general page is 76X102cm bar, the difference of the page will be a little smaller, in order to save the cost.
5, another way of cutting off material is that the thickness of the hinge is not enough. The page can be 3mm thick and the difference page is thin.
6, the good hinge of the damping oil will not leak, this point is not good to observe, only ask the dealer.
I personally feel that most of the big factories do not have much problems. I suggest you find a good hinge for building materials city according to the way I introduce.