Screw threadThe difference between local and overall bending straightening. Determining the position of the screw bending is crucial; whether it's a local bend, an overall bend, or a small amount of bending versus a large amount, will then dictate whether manual straightening or the use of a press for straightening is appropriate.

During the straightening process, the use of machine tools for auxiliary support surfaces is generally unnecessary, as the lathe often fails to achieve the desired straightening effect. This is primarily due to the fact that machine tools typically employ flame or impact methods for straightening, which can affect the screw threads. This method often leads to significant centrifugal forces during rotation.

If the screw shaft is experiencing overall bending, it is recommended to use a press for straightening. Simply place it on a mold iron, then use the naked eye to observe the straightening effect.

If the bending is localized, the better method for straightening is by hand. The technique is the same as for overall straightening; by hand, it involves repeatedly hammering the bent screw position with a large hammer to achieve the desired straightening effect.