... -1/2" 6" 7" 8" 10" 3. Screw spike mostly used in South American and Africa with big disk Diameter22mm 23mm Length115mmm ... 5.6 , according to the standard NF-F 50014 . 9 Special screw spike 23×174 , fix the rail together with the Nabla ... ,We use the special material TD16 to produce the screw to meet with the bending test , bending 30 degree and straightening it , without ...