I noticed how any impact I use has a little 'wobble' in the bit. Really noticeable in a long Philips or a spade bit. I own a Ryobi, but I have used Rigid, Bosch, and Dewalt. Every one with the same thing. Is this meant to be? Will it cause problems when driving screws into my projects?

  • 2
    Not strictly woodworking related, this is the sort of Question probably better asked in another SE.
    – Graphus
    Apr 17, 2017 at 6:44
  • 1
    Are you predrilling when you use your impact driver?
    – rob
    Apr 18, 2017 at 1:03
  • @rob Yes I do. My regular drill does the drilling then I use the impact for screwing. It works better for me. And in many cases, can go faster.
    – Ljk2000
    Apr 18, 2017 at 2:54
  • @Graphus Impact drivers are used in woodworking, and questions about tools are on-topic here, so I think it can be left open. I do agree that it might be better for another stack, though.
    – mmathis
    Apr 19, 2017 at 15:04
  • 1
    The bigger issue is there are two separate questions here - the wobble and a more general comparison of impact driver vs drill. I've edited the question to be specific to the wobble, so if you want to ask the other part @Ljk2000, you should ask a separate question
    – mmathis
    Apr 19, 2017 at 15:06

4 Answers 4


I'm going to address the "what advantage would there be over a regular drill" part of the question first.

Impact drivers are much better at driving fasteners, drills are much better at drilling. (Hence the different names...)

When you're drilling you want a thin, continuous cut. This means that you normally don't need a ton of torque, but you want it continuously. Drills are built to do this because they just turn at full torque the whole time.

With a fastener you don't really care if you stop and start, but you want as much torque as possible. So an impact driver applies more torque, but it does it intermittently (hence the "clicking" when you use it.) This also has the added benefit of not causing "reaction" torque, when a drill binds up and tries to twist your arm. So you can apply a lot more torque with an impact than you ever could with a drill.

All that said, since an impact is intended to be used with fasteners it doesn't really matter if it wobbles. You're normally using it on something that isn't prone to walking around like a twist drill bit does.

  • now that I think of it I did have all the fun with the drill twisting my arm. Which is one of the big things I love about the impact, no twisting.
    – Ljk2000
    Apr 18, 2017 at 2:58
  • Additionally, an impact driver typically has a hex or square drive for bits that has high strength and a quick change. The wobble is not important and is a side effect of that design. A drill cannot wobble and has to accommodate many sizes of drill bits, and thus has an adjustable chuck.
    – mbmcavoy
    Apr 18, 2017 at 19:13
  • 1
    The impact also applies that torque intermittently, or "pulsed" between each hammer blow (yes, there's a little hammer inside :) which allows the bit to re-seat in the screw head. This is why bits and screw heads, Phillips in particular, last much longer with an impact driver. They don't have the same tendency to "cam-out" that they do with a drill-driver.
    – scanny
    Nov 8, 2018 at 17:11

In my experience impact drivers have a short head with a short hex-shaped recess to receive bits and drivers, where a drill has a chuck with a much firmer grip on bits. Hence the greater wobble factor using the impact driver. An impact driver is great for rough framing where I am not predrilling for screws, but I do not use it on better quality woodworking projects. For me it is like the difference between a broad heavy masonry chisel and fine woodworking one. Different tools for different applications.


All impact drivers have deliberate nose wobble so the bit centres itself in the screw used eg square , philips, flat etc

  • 1
    Well, it's deliberate in that the impact movement requires movement in multiple axis, which naturally leads to this sort of wobble to some tolerance. You should produce some evidence that this is a specifically engineered feature for interacting with fasteners. Because if that is what you are suggesting, I don't think this is correct.
    – user5572
    Jun 26, 2019 at 13:13

An impact driver is primary a single purpose tool for installing or removing threaded fasteners, at this it is very good. Much less striped heads or broken screws, and less torque on your wrists. In short if you drive screws you need one. Ditto to most of what was said above but I use mine for all screws.

  • 2
    This does not answer the question.
    – Kromster
    Nov 9, 2018 at 12:38

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.