What Torque Really Means

Power Tools: What Does Torque Rating Really Mean?

Cordless tools have come of age. Now, newer technology allows cordless tools to perform on or near par with their corded counterparts. You might want to take another look at performance standards to make sure you’re getting the cordless tool you really need to complete your jobs effectively and quickly. 

A New Way To Look at Power
The key to drill performance is being able to deliver the required torque at the highest speed. A common misconception is: the higher the torque rating, the faster the drill will complete an application. That’s not necessarily true. 

Torque is the force the drill produces to turn an object, not how fast an object will turn. In recent years torque ratings have been steadily increasing to levels beyond what is actually needed to complete applications. A new way to measure the performance of a drill is to combine speed and torque, a measurement called Power.

Performance Ratings
  • Power can be measured by the ability of a device to produce work.
  • Power is measured by the formula: Speed X’s Torque/K = Power
  • K is constant and varies depending on the units used to measure torque
  • Speed is how fast the drill turns (revolutions/minute)
  • Torque is the force the drill produces to turn an object
  • Power is the amount of work completed in a given period of time

Traditional Measurement Method for Torque Rating:T
  • Mounting drill into rig
  • Locking chuck onto a fixed spindle
  • Drill is fully powered
  • Measures drill torque level at 0 rpm (does not measure speed)

New Measurement Method for Power Rating:

  • Mounting drill into rig
  • Locking chuck onto a rotating spindle
  • Drill is fully powered
  • Torque loads increasingly applied
  • Measures drill speed and torque with multiple data points

The Power Rating
A drill’s Power Rating has been used for many years as a tool to design products. It is not until now that it will be used as new way of evaluating a drill’s performance level, and is a direct indication of how fast it will complete an application.

The drill’s Power Rating is measured by its Units Watts Out (UWO), the point where the drill’s speed and torque output are the highest. The higher a drill’s Power Rating, or UWO, the faster it will perform on the jobsite.

Torque ≠ time to complete applications Power = Speed & Torque output under load Max Watts Out (MWO) = Power of the motor Unit Watts Out (UWO) = Power of the total drill 

This article is from the July issue of Grainger’s On the Job® newsletter.