As I am sure you know, most cordless drills have multiple speed ranges. Most have 2 gearbox settings, and some – mainly Dewalt’s premium models – have 3. This is all besides the variable speed trigger.
You might see a drill’s speeds represented as 0-500/0-1800 RPM, as an example.
Generally, the higher speed and lower torque range is used for smaller diameter drilling tasks, and the lower speed and higher torque range for larger bits and tougher tasks. The lower speed range is also usually better for driving and fastening tasks.
Some accessories typically have maximum speed ratings. My self-drilling spade bits, for example, should not be run faster than 1500 RPM.
Hole saws also have recommended speed settings. A Milwaukee Hole Dozer 2″ bi-metal hole saw, for instance, has a recommended speed of 255 RPM for drilling aluminum, and 170 RPM for mild steel.
When drilling with a twist bit, such as 3/16″, I’m often in high speed mode. Spade bit such as 1″? I’ll switch to low speed mode. Fasteners? My drill will be in low speed mode and I will often dial in the adjustable clutch for repeatable torque.
When in doubt, there are drilling speed charts. Recommended speeds depend on the accessory type, size, and material, what you’re working on, and sometimes also on the tool.
Do you change your drill’s speed setting? When? Why?
Or do you run as much as you can at high speed? This isn’t recommended, but I’m finding that a lot of people do it anyway.