(1) Thread cleaning
Use kerosene to clean the dust, oil, rust, etc. on the thread, and remove the rust with a copper wire brush until the foreign matter at the thread is removed.
(2) Correction of bolts
The bolt is bent and can be corrected. There are two methods: one is the cold work straightening method, which is similar to the method of correcting the thread of the valve stem (see the valve stem repair section above); the other is to clamp a nut on a vise and twist the bolt by hand. Screw the bend into the nut until it feels hard to handle, then screw on another nut above the bend of the bolt to protect the thread, and then slowly tap the nut with a hammer (or wrench) to turn the bend in the opposite direction Correct, knock, tighten the bolt until the bend is corrected.
(3) Repair of too tight thread
There are three ways to eliminate the thread fitting that is too tight: one is the cleaning method, which cleans the thread to remove the oil and rust layer to eliminate the over-tightening; the second is the thread method, which uses a die or a tap to re-thread the thread; the third is In the grinding method, a layer of abrasive diluted with kerosene is coated on the bolt, and the nut is screwed on and turned and ground repeatedly to repair it.
(4) Repair of loose thread
There are three repair methods: one is the retention method, if the bolt is worn out, you can retain the bolt and replace the nut; the second is the cementation method, which is coated on the thread with anaerobic glue or other adhesives. Fastening and anti-loosening effect; the third is coating method, which is repaired by zinc or chrome plating.
(5) Thread flattening and lap repair
There are three repair methods: one is the filing method, which uses a triangular file to trim the thread; the second is the chiseling method, which uses a small chisel to cut and circle and flatten the place; the third is the threading method.
