How to remove a broken screw? (Tough)
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During a recent maintenance task, we encountered a situation where the screws were broken in such a way that it was practically impossible to remove them. Here’s what happened: there are six M16 threaded holes on the shaft seal, and three of the bolts had 10mm-long sections broken off inside the holes (the broken ends were 2-3mm below the surface of the shaft seal). We tried to twist those broken sections by drilling holes and inserting rectangular hardened iron bars, but they didn’t move at all. Later, we tried using a left-handed screw extractor, but that also failed. There are strict restrictions on using open flames at the work site! What else can be done in such a situation? I hope experts can give some advice!
Once the screw breaks, a hole can usually be drilled, and it can be removed using a bolt extractor. If that doesn’t work, then there’s only one option: use fire to set it on fire.
:Loveliness: In such a situation, the smartest solution is to replace the shaft seal. Because even if you manage to remove it, it is likely to affect the precision requirements of the shaft seal. . .
If work involving fire cannot be carried out in this situation, it seems the only option is to replace the shaft seal
You can also use a sharp object to press against one side of the bolt head, and then use a hammer to tap gently, causing the bolt to turn and gradually come out.
Replacing the shaft seal is almost impossible! Since this stuffing box is welded to the machine, the shaft has a diameter of 300 mm and there is limited space for operation; a 12 mm hex key can just be used for manipulation, and a small drill bit is also suitable, but the drill bit cannot be too long! If welding is done, there’s alcohol inside the kneader! Are there any more ideal suggestions?
There isn’t a very good solution; the 300MM shaft seal is quite large. Consider dealing with the equipment first; clean the medium until it meets the conditions for working with fire, and then replace the shaft seal.
After drilling, use a tap to reverse the thread direction and then remove the broken bolt
If the hole is small, you can try using an impact driver to see if you can drill it out. As you said, if only a small electric drill can be used to drill the hole, it will definitely be too small, and it won’t achieve the effect of relieving stress; in that case, you can find ways to enlarge the hole diameter.
Drill directly using a tap smaller than M16, paying attention to the depth of the screw hole.
Use a drill bit sized 14 to drill a hole and remove the screw