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What is a Thread Repair Kit?

Apr. 17, 2021


The Thread Repair Tool allows the damaged thread in the hole to be removed and replaced with a new thread of the same size. They can also be used to provide strong threads in soft materials.


Threaded taps

Threaded taps


The thread repair tool includes a tapping tool, an insertion tool and thread blades. The use of the thread repair toolbox also requires a drill bit and a Threaded taps. The drill bit may or may not be included in the kit.


The most common thread blade in a thread repair kit is a spiral blade, often called Helicoil. The spiral blade looks like a tightly wound spring. It is composed of a spiral wire wound by a steel wire with a rhombus cross-section.


One end of the helix has a small convolution that engages with the insertion tool so that the insert can be screwed into the hole. There is a small groove in the steel wire, once the blade is installed, this return stroke can be cut off.


The process of using a spiral blade to repair the thread in the damaged hole has the following steps:


Use a drill of the correct size to drill out the damaged thread.


Tap the hole with a special thread to accept the threaded blade. The required taps are included in the thread repair kit.


Use the insertion tool to screw the threaded insert into the hole just below the surface of the part.


Unscrew the insertion tool. When the torque of the insertion tool is released, the threaded blade will slightly expand. This will cause it to lock onto the part.


Pass the thread of the threaded insert through the hole and snap it off. A punch or hex tool can be used to insert the new thread so that it is against the alveolar. It can be buckled by hitting it with a hammer.


There are many ways to damage the thread. If the external thread is damaged, such as on a bolt or screw, it can usually be cleaned by running a mold on it. When the thread is slightly damaged, the thread can be repaired by simply sliding the nut up and down, but there is a risk of fusion between the nut and the thread. This process is called biting. Therefore, it is safer to use the mold first.


When the thread is peeled from the hole, there are several options. One option is to drill a hole and then tap it with a larger diameter thread. If there is room for larger fasteners, this may be a good choice. When it is impossible to create a new larger tapping hole, a thread repair kit can be used.


The company also provides internal and External Thread Cutting Tools, if necessary, please feel free to contact us.