Is high speed and low torque better than low speed and high torque?

How to adjust speed and torque settings on your drill for sewer cleaning with a flexible drain cleaning shaft


There are a few factors to consider when answering this question. What kind of job do you plan on executing? Which tools will you be using? What kind of power source do you have?

Torque and speed settings for descaling and blockage removal

If you are using the tools for descaling a pipe, then you will need less torque and more centrifugal force. The reason is that the momentum of the chain is important for knocking off the tuberculation, limescale, urine scale, or rust. That is why you will need higher speed and lower torque to centralize the chain in the pipe using centrifugal force.

When it comes to blockage removal, you will need more torque and less speed. The reason for this is that when you are removing a blockage, very often that blockage needs to be ground up, so you would need more torque for the root cutting tool to grind up thicker roots. More torque is required even with thinner roots.

The less solid blockages like fatty deposits and wet wipes would also benefit more from higher torque versus higher speed. Torque is a much more important factor here. Having said that, this is only when the blockage has filled the pipe. When the pipe is not full of that soft blockage the chains will obliterate and grind up the soft blockage easier using higher speed. 

We have created a short video demonstrating how to correctly adjust your drill settings. This video can be very useful in preventing accidents, injuries, and damage to your flexible shaft:

Lightweight or heavy-duty chains?

Please note that a heavy-duty chain requires more torque than a lightweight chain. With a lightweight chain, you could use a smaller power source to get the same effect. Heavy-duty chains are designed for a bigger power source, and they are meant to be used with 10mm (⅜”) and 12mm (½”) flexible drain cleaning shafts.

Another thing to bear in mind is that if you are using a plain chain with a crown drill head ( inside a PVC pipe, then it is imperative that you reduce the amount of torque as you pass through a 90 degree junction to prevent the crown drill head from biting into the pipe wall of the junction.


Choosing the most appropriate drill settings highly depends on the type of job that you plan on doing and on the kind of tools you have available.

If you need to descale a pipe, then you will need more centrifugal force. If you are removing a blockage, then you should use more torque. Please note that if you are removing a soft blockage that hasn’t filled the pipe entirely, then it will be easier to do so using higher speed settings.

Lastly, please take your power source into consideration when choosing the appropriate tools for the job that you plan on doing.