I need to use self drilling screws shown below to attach something to a piece of metal. First time user of a cordless drill with so many settings. Do I use the drill setting at low speeds or the driver setting and adjust the clutch setting?
With my variably speed drill (with an adjustable clutch), I usually start out fast until the screw starts to penetrate the 2nd piece of metal. Then I slow it down and snug it up gently. Like others have said, it's easy to over tighten and strip out the holes, especially when working with light weight aluminum like is found in gutters and downspouts.
I am assuming that you're mating two pieces of relatively thin metal, right?
If your drill trigger is pressure sensitive then just take it slow until the metal is firmly attached. Don't overspin it because it could make the screw difficult to remove in the future.
If you try using a specific clutch setting then you will find that it suffices less than 50% of the time. Some times it won't pull tight enough and you'll have to increase the clutch and other times it will overspin the screw.
There's no secret really, just pay attention.
If you're expecting to perfectly use a drill on your first try then you're in for a world of disappointment. Do a few practice screws first. Also, practice screws are how you would even figure out the correct clutch setting in the first place. One of my drills goes from 1-100 and another goes 1-20. The drill with the 100 is more powerful than the 20 so there isn't even a direct conversion.
If you're really paranoid then screw it in only 75% of the way and then use a screwdriver or socket wrench to finish the job.
I will usually click the appropriate socket onto a 1/4" socket adapter and click it into my impact driver. The impact driver (very different from an impact wrench - much lower torque) has two settings Forward and Reverse, so I'm not really sure it makes a lot of difference.
My drill has two torque/speed settings. I couldn't begin to tell you what the difference is between 1 and 2 - I can't hear a speed difference, though I've checked every now and then. I'm sure it's in the manual which is... around here somewhere... Honestly, maybe I should, but I basically never switch the "speed" setting.
Since you've got a clutch on yours, you may want to set it to a somewhat lower setting, then increase it as necessary. As a new user, you're somewhat more likely to continue spinning the screw once it's fully seated which can strip out the threads that the screw has cut, leaving the screw to spin in the hole and no longer actually hold the metal. By setting the clutch below the "drill" setting, it will stop turning once the torque passes the clutch's setting. If the setting is too low, it won't set the screw at all, but you can simply go to a higher setting until it gets as tight as necessary.
Too much torque can snap the head off the screw or tear up the hole so start with low torque
Use high speed, and plenty of pressure. start with the cluch io the low setting, and if it's slipping before you're finished setting the screw increase the clutch setting, having determined sufficient clutch you can use that setting for the rest of the screws.