If you have a do-it-yourself mentality, you have encountered those stubborn screws that simply do not come out no matter what. You can use your electric driver, you can heat them up, you can hit them, you can scream at them – some stupid screws just don‘t want to come loose. There is a solution – an impact screwdriver, but how does it work?
There are many reasons why some screws don’t want to come undone. They may be affected by corrosion, some may be just a little too tight or even glue might be involved. However, the most common reason is shifting materials. Screws are holding at least two different parts together. If they shift in relation to one another the screw wedges itself tighter in its threads. It becomes stuck and it requires a little more torque to come loose. Situation is worse if it’s a Philips’ head screw, because those are designed to spit out the screwdriver if too much torque is applied. And that is where the impact screwdriver comes in.
The way to undo a stuck screw is to apply a lot of pressure so that the screwdriver wouldn’t cam out and a lot of torque. An impact is the best bet, because a sudden twist may break whatever the tension holding the screw is. So you put your impact screwdriver, hold it firmly in place and administer a firm hammer blow to the end of it. It may not feel like much has happened, but the screw will turn ever so slightly, breaking the bond and coming out easily with conventional tools. How does it work?
Well, an impact screwdriver essentially is made from three crucial parts – the driver end, the handle sleeve and the spring. Handle is hollow, it houses the spring, which pushes against the driver end. To put it simply, the driver is not rigidly attached to the handle. You may think it is just because of how stiff that spring is though. And so the driver is free to turn in relation to the handle. However, the way it is attached there is an inclined slot and a pin. When you whack the handle with a hammer, it pushes itself forward compressing the spring and pushing that pin deeper in the slot. Because that slot is at an angle, the driver is forced to turn. It is just a couple of degrees, but it is enough to make a difference.
Essentially, an impact screwdriver turns a linear motion (impact) into a sudden turn. It is quite fascinating to see it doing its job, but it works. And it is not even that expensive of a tool – this from Gearbest.com comes with a case and several different bits and still costs just €20.74. It is a great addition to your toolbox and one that you should not wait till you need it.