We've all heard that unsatisfying creak as a bolt head shears, but removing a broken stud is nothing to worry about. John Simister explains...
This is not an Octane crusade to encourage a post-punk removal of body adornment. Instead it’s a brief guide to recovering from the despair depth that accompanies the feeling of no return as a threaded stud, perhaps in a vital part of an engine or a suspension system, snaps off instead of relinquishing its nut.
There might be enough of a stump to allow a Mole-type self-gripping wrench to grasp it and let you wind the stub out. Soak the area with penetrating fluid and leave it. If there’s a chance of heating the area safely with a small blowtorch, then that will help loosen the grip on the stud. Sawing a screwdriver slot across the stud’s remains, and attempting to unscrew it, is also worth a try.
No luck? Time for the drill. You could drill the stud right out, using a bit a little smaller than the diameter of the stud at the bottom of its thread. That way, you stand a chance of not ruining the thread into which the stud is supposed to locate. This method is fraught with hazard because, if you damage the thread, the stud-hole will have to be drilled out to a size big enough to be tapped in preparation for a new threaded insert such as a Helicoil or a Time-Sert.
Or you could be brave and use an ‘Easy Out’ or similar extractor. This is a hardened steel rod with a tapered end threaded in the reverse direction from normal. You drill a hole in the remains of the stud, smaller than in the method above, and screw in the extractor. If it works, it will cause the stud to be wound out as the extractor grips it. The danger is that if the extractor snaps you’re in big trouble because the steel is too hard for many a drill bit to munch into.
You’re then on your last chance, which is to take the item to a suitable specialist for a dose of spark erosion. Carefully-controlled sparks jump the gap between an electrode and the bit you want eroded (the stud) until you are left with the hole you need. With care the thread can be left intact, otherwise it
will be drill, tap and threaded insert.
So don’t worry: all is not lost when that stud snaps off.
Words: John Simister