The straightness of the stainless steel allen head cap screws also affects the screw-to-screw assembly, so there are also some customers who require the straightness of the screws. So how to measure the straightness of the screw? The straightness of the stainless steel allen head cap screws is the same as the surface defect, which has a great relationship with the judgment of the inspector, and is different from the measurement indexes of strength and hardness. Therefore, any scientific testing instruments and devices, any perfect testing methods, can not be perfect. Only make the product less defective, or if there is a defect, try to take measures to correct it, such as straightening the long rod screws with excessive straightness. Straightness measurement method using straightness measuring device: ★Place the stainless steel allen head cap screws to be measured between the fixed rail and the adjustable movable rail. Tak...