1, look look, take a few more swing chain watching to see whether the way the hinge remained one to many poor plant produced hinges hinges here, where black and yellow, unstable plating, electroplating and thin, so it is easy to rust.
 
2, holding the iron chain hinge cup, slowly closing as the way to close the hinge, remember to slow, if you feel that the hinge is very smooth, not hindered, and even try some are very smooth, then this initial hinge products is often qualified. If you find the middle of obstruction or noise, or even both, then you should be careful whether the quality of this hinge problem.

3, loading door, the little downward pressure force about to see the force hinge situation, if it was sinking, and more serious, then you have to be careful after the door now appears as an asymmetry.

Author: River supernatural power chain Co., Ltd
website: www.shenlichain.com
main product: swing chain、iron chain