Why Does My Flexible Shaft Keep Coiling Up?

If your flexible shaft becomes tangled or difficult to push, there are two likely explanations. Understanding the cause will help you adjust your setup and avoid unnecessary frustration.

1. Tangling Outside the Pipe

If the shaft tangles before it even enters the pipe, it’s likely due to excessive inertia. When a rotating shaft builds up too much energy and isn’t stabilized, the free (exposed) part of the shaft can start to twist or coil in unpredictable ways. This kind of tangling is usually a sign that the shaft isn’t being guided properly or is running too fast without enough tension or control.

2. Difficulty Moving Flexible Shaft Inside the Pipe

If the shaft enters the pipe but becomes hard to push or starts coiling up inside the pipe, the issue is likely related to shaft diameter.

A common mistake is using a flexible shaft that’s too thin for the pipe size. For example, a ¼ inch (6mm) shaft used inside a 6-inch (150mm) pipe is too small for the job. At first, it might seem to work fine, but after a certain distance, the shaft begins to spiral along the inner wall of the pipe. This coiling increases resistance and makes it harder to move forward.

How to Fix It

To prevent this, always match your shaft diameter to your pipe size. A thicker shaft will stay more rigid and travel straighter inside larger pipes, reducing the chance of tangling or spiraling.

In short:
Tangling outside the pipe = too much inertia, poor control
Tangling or resistance inside the pipe = shaft too thin for the pipe diameter

Make sure you’re using the right tool for the job, and your work will be smoother and more efficient.

For a more visual explanation, please take a look at this video.