The numbers are clutch settings for screwdriving. A lower setting makes the clutch slip sooner. A higher setting allows more torque before it slips.
On the DEWALT DCD771, the numbered range is 1 through 15. The manufacturer tells users to start with lower torque settings and work upward until the fastener seats the way they want.
What happens when the clutch slips?
You usually hear a rapid clicking or ratcheting sound. The motor can keep running while the chuck stops applying more driving force.
That sound does not automatically mean the drill is broken. If the screw is seated where you want it, the clutch may be protecting the screw and the workpiece from additional torque.
What number should I use?
There is no reliable universal chart that says, for example, setting 6 is always right for a 2-inch wood screw. Material, pilot hole, screw size, bit fit and the drill itself all change the answer.
A simple method works better:
- Start lower than you think you need.
- Drive a test screw.
- If the clutch clicks before the screw reaches the right depth, move up a few settings.
- Repeat until the screw seats without burying itself too deeply.
What is the drill-bit symbol?
That is drilling mode. On the DCD771, you use it for drilling holes rather than a numbered screwdriving setting.
The numbered collar around the front controls clutch torque for screwdriving. The 1/2 selector on top changes the drill’s mechanical speed range. They solve different problems.
Here is the separate speed 1 vs. 2 explanation.
A practical example
Suppose you are assembling a shelf and the screw head should finish just below the wood surface. Start low. If the clutch clicks with the screw still sticking out, increase the setting. When the screw reaches the right depth and the clutch begins to slip, you have found a useful setting for that screw-and-material combination.
Change the screw, pilot hole or wood and the right number can change too. That is why memorizing somebody else’s favorite setting is less useful than understanding what the clutch is doing.
When to ignore the numbers
For drilling holes, use the drill mode specified by the manual rather than trying to find a very high clutch number. The clutch is a screwdriving control. It is not a numbered hardness scale for wood, metal or masonry.
Why this feature can save screws and furniture
Without a clutch, it is easy to keep driving after the screw is seated. That can strip the screw head, tear out the material or bury the fastener much deeper than intended. Once you get used to the clutch, it becomes one of the nicest parts of a drill/driver rather than a ring of mysterious numbers.
Sources used for this answer
Back to class: Cordless Drill Class.