back rest pin roll
pin roll
Billiard thread
Coupling thread
Goose egg thread
Plum blossom thread
Cutting thread
Faecher thread
Double-end bolt
Screw rod 
Acme thread 
Pin roll
Shoe-shaped gold ingot thread
Thread with compression steel
back rest pin rollpin rollBilliard threadCoupling threadGoose egg threadPlum blossom threadCutting threadFaecher threadDouble-end boltScrew rod Acme thread Pin rollShoe-shaped gold ingot threadThread with compression steel