1. The Rivets have to be very strong and precise  for this mechanism,we used lastest advanced machinary to make this products.

2. This mechanism is free of size but better for maximum 60". The front board locks the open position therefore this board needs to be reinforced.

3. The wood frame needs to be exactly square and cross lines have to be equal.

4. The good idea for wood frame maker is to use 2 wheels in the floor and another 2 wheels run in the surface of bottom polywood.

We add the safety lock design in case front board is not strong enough.