Impact screw drivers?

[oldnslo]

Can someone please explain why the impact drivers strip out fewer screw heads. I've read this before but can't figure out the reason.

Impact keeps driving the bit into the screw head while a drill at constant torque tends to want to force the bit out of the screw head.

 

[oosik]

Thank you LD1. That's exactly the information I was looking for.

 

[LD1]

Can someone please explain why the impact drivers strip out fewer screw heads. I've read this before but can't figure out the reason.

The impacting. They impact forward (into the screw) as it is turning

 

[stuckmotor]

Oldnslo and LD1,
Thank you for the explanation. That question has been on my mind for a long time.

 

[texasjohn]

Oh, gosh, next visit to Harbor Freight is going to be expensive.

 

[davrow]

I just recently got my first cordless drill and impact driver (Ryobi kit). Didn't know which I would use for driving screws. Well, the drill is for drilling. That's it. The impact driver is for everything else. Fully variable trigger speed, so I can start real slow and ramp up.

I don't know how I lived without them.

 

[Brant]

The inertia of the tool and your arm help you. You do not have to resist the full driving driving torque with your wrist. I can drive a 3" deck screw holding the impact driver over my head with one hand. Good luck with a drill. Impact driver are great for structural screws too.

 

[fordmantpw]

If you haven't used one in 'real life', then you don't know what you're missing. When we had our home built, I used the contractor's impact drill to build some shelves. Wow, what an amazing tool! If I had the extra money laying around, I'd buy one now and never use my drill to put screws in again!

 

[LD1]

With the hex to 1/4" square or 3/8" square adapter bits they can use sockets too. And they are pretty handy for assembly and removal without dragging out the air hose. Now it aint gonna torque the lug nuts on your tractor, but for small fastners it is handy.

 

[varmint]

Having used battery drills and impact drivers for years, I have learned that the newer lithium batterys are great, in that they will hold a charge almost forever, and don't taper off with use. When they die, they die. I have a little 3.6V Makita driver that was something they only briefly marketed- lithium, well made, and purchase on clearance at HD for something like $30. For screws, not lags, it is hard to beat. My more powerful stuff is all cadmium battery, and getting older, so they don't hold a charge well. But then, so am I, so we'll see what goes first.