Which Flexible Shaft Should I Use for 1.5-Inch Pipes?

If you’ve ever tried descaling or removing blockages in a 1.5-inch (38mm) pipe, you’ve likely run into a common challenge: finding the right flexible shaft that can navigate the tight bends and narrow diameter. Let’s break down what works, what doesn’t, and what you can do to make the most of the tools available (we’ve also made a video on this topic, so please check it out here).

The Short Answer

When it comes to 1.5-inch pipes, no flexible shaft is truly ideal. While a 6mm (¼-inch) shaft might technically fit due to its bending capacity, the reality is more complex. These shafts start to struggle once multiple bends are involved. That extra bit of stiffness becomes a problem, making it difficult to maneuver through tight turns.

Why It’s an Issue

The main problem lies in the relationship between the shaft’s flexibility and the pipe’s bend radius. In 2-inch pipes, the quarter-inch shaft performs well because its bending radius matches that of a typical 90-degree bend. But in 1.5-inch pipes, the tighter bends push the shaft beyond its capabilities.

A Workaround (But Not a Perfect One)

If you’re set on using a 6mm flexible shaft in a 1.5-inch pipe, there’s one modification that might help: remove the sleeve bearing at the end of the shaft. The sleeve bearing, while useful in other situations, can increase the chance of snagging on corners or joints. Taking it off might improve maneuverability slightly, though it still won’t make the shaft an ideal fit for the job.

Final Thoughts

Whenever possible, try to avoid using a 6mm flexible shaft in 1.5-inch pipes. It’s not designed for such tight spaces, and while small modifications may help, they’re not guaranteed to solve the problem entirely. For now, the best solution might be avoiding these pipes altogether with this setup—or waiting until a better-suited tool becomes available.