How to Remove a Broken Tap, Stud, bolt

How to Remove a Broken Tap, Stud, bolt

When drilling in wood, metal, concrete and other building materials, everything does not always run smoothly. Sometimes it even happens that a drill breaks off – this has happened to me many times. It is particularly bitter if it is deep in the hole and cannot be easily pulled out. In this article, I’ll show you ways to remove a broken drill and what you can try on which material.

The fact that a screw breaks off, turns round or gets stuck in the workpiece can have the following reasons:

The screw is:

  • Very old, rusted and thus weakened.
  • broken off due to too much tightening torque.
  • made of soft material and not suitable for application.

Method 1: Using snap ring pliers to remove broken Tap

The first way to remove a broken tap from the workpiece is to remove it with the help of a snap ring plier.

The prerequisite for the method with the snap ring pliers is that the tap does not protrude from the borehole. The snap ring pliers are placed in the drill hole and grab the grooves of the tap.

Careful attempts are made to loosen the tap and the canted material by means of slight rotary movements.

Method 2: By welding a nut

One common method for removing a broken bolt is to weld a nut onto the end of the bolt stub, then use a wrench to turn the bolt out. Here are the basic steps to follow:

  1. Clean the area around the broken bolt thoroughly, removing any dirt, grease, or other debris.
  2. Place a nut of the appropriate size onto the end of the broken bolt, making sure that it is centered and level.
  3. Use a welding machine to tack-weld the nut to the broken bolt. Be sure to make a solid connection, but do not weld the nut to the bolt too strongly or it may be difficult to remove later.
  4. Allow the weld to cool for a few minutes, then use a wrench to turn the nut counterclockwise. Apply steady pressure until the bolt starts to turn.
  5. Continue turning the bolt until it is fully removed. If the bolt is very tight or difficult to turn, you may need to apply heat to the area around the bolt with a torch to loosen it up.
  6. Once the bolt is removed, use a wire brush to clean up any remaining welding debris or residue around the hole.
  7. If necessary, replace the bolt with a new one of the same size and strength.

Method 3: By drilling the tab

If a tap is broken, the classic solution is to drill out the tap. For this purpose, protruding parts of the broken tap must first be separated. Then first drill the uneven surface of the broken tap to get a clean guide during boring.

In the next operation, carry out the boring and pay attention to a uniform feed. Then clean the borehole.

With this classic method, when the tap is broken, it depends above all on tact and is not an easy task. Damage to the workpiece is also not excluded.

The method is to select and drill a drill according to the lower diameter of the pin thread. A very difficult path, it requires skill.
First, we go through a smaller diameter drill.

Then we drill as close as possible. We knock out the fragments and remains of the bolt with a flat screwdriver.

Method 4: Using Tap Extractors

The easy way to remove a broken tap with the threaded crown

A broken tap can be removed much more conveniently by using a threaded crown. The method of removing broken taps can be applied anywhere and does not require time-consuming preparation. A significant advantage here is that the workpiece and its statics are not changed and subsequently after the broken tap has been removed, the thread can be drilled out again.

Threaded crown for broken taps

A thread cutter has so-called flutes. Depending on the type of tap, this can be 2, 3 or 4 grooves. The threaded crown is also available with 2, 3 and 4 bars and is therefore the matching counterpart for the tap.

To remove the broken tap, the bars of the threaded crown is inserted into the grooves of the broken tap if necessary help with light hammer blows.

With a winding iron, you then turn out by means of the threaded crown with sensitive back and forth. The broken tap is removed from the workpiece against the thread direction.

Remove broken taps using the threaded crown in 3 steps

  1. Remove smaller fragments, e.g. with a needle or similar.
  2. The threaded crown is inserted into the flutes.
  3. With a wind iron, the fragment in the workpiece is now loosened by sensitively moving the threaded crown back and forth and screwed out against the thread direction.

Prevention to avoid drill breakage

Finally, here are a few tips for you on how to largely avoid a drill break or minimize its chance:

  • Clamp each drill firmly and securely. Check this again before you start drilling.
  • Do not drill with too much feed and an adapted speed (I have already made recommendations in various tables on this website).
  • Do not make jerky movements when drilling and do not try to change the drilling direction by brutally twisting the drill.
  • Be sure to use the correct drill for each material.
  • Before use, consider your drills with regard to the already existing wear.
  • When drilling in metals, always have enough coolant on hand and use it during drilling.
  • With small diameter drills, pay much more attention to ensuring that they do not break – because they are more likely to do so due to their low thickness.

In general, always be concentrated when drilling and focus on this work. Carelessness and negligence can not only lead to serious injuries, but also cause a drill break.

Material Welding is run by highly experienced welding engineers, welding trainers & ASNT NDT Level III bloggers. We strive to provide most accurate and practical knowledge in welding, metallurgy, NDT and Engineering domains.