What Is an Impact Driver?
An impact driver is a type of electric screwdriver used for tightening screws and drilling holes.
It is a powerful product that can apply not only rotational force but also impact force. It is characterized by its high power and can tighten screws at higher speeds than ordinary screwdrivers.
Also, by replacing the bit on the tip, products that can tighten bolts, nuts, etc. are available.
Uses of Impact Drivers
Impact drivers are used to improve work efficiency. Specific uses of impact drivers are as follows:
- Assembly work at construction sites
- DIY woodworking
- Maintenance work in factories, etc.
All of these tasks can be performed without the use of power tools. However, the use of impact drivers and impact wrenches improves work efficiency.
In addition, because the fastening is done electrically, there is no variation in fastening force due to the force exerted by the operator.
Principle of Impact Drivers
Impact drivers consist of an anvil, a hammer, a spring, and a motor battery.
1. Anvil
The anvil is a device that holds the part called a bit. In the case of impact drivers, a Phillips-head or flathead screwdriver is used for the bit. The anvil is fastened to the hammer and rotates with it to turn the screwdriver together.
2. Hammer
The hammer is the part that strikes the anvil to give impact. The fastening part with the anvil has a groove cut at an angle to allow play. When the set stress is exceeded, the fastening part is released and impacts the anvil.
3. Spring
The spring is the part that presses the hammer. It is also called a hammer spring. It always presses the hammer against the anvil and is responsible for applying force to the hammer.
4. Motor and Battery
Most impact drivers are powered by a DC motor and a battery. The battery power is converted to rotational power by the DC motor. Some products have a removable battery, while others have an integrated battery.
How to Select Impact Drivers
When selecting impact drivers, there are three important criteria:
1. Shape and Size
Impact drivers come in several shapes. The most common is a shape in which the handle and the tip of the bit are at a 90° angle. There are also pen-type drivers available, in which the head and handle are in a straight line.
Some pen-type products can be used with the handle bent at 90°. If the work area is too small to fit impact drivers, a pen-type with an adjustable handle angle is useful.
2. Torque (power)
Torque is one of the performance indicators of impact drivers. Torque is a unit of tightening force and is expressed in Nm (Newton-meter). A higher torque value will give you a stronger tightening force. However, with a higher torque value, the weight and price will also be higher.
When using a screwdriver, care must be taken due to the risk of crushing the screw threads. Select the appropriate one according to your budget and usage scenario.
3. Bit Shape
When using impact drivers, it is possible to tighten various materials by changing bits. Since the bits supported by different types of screwdrivers differ, select a screwdriver that matches the bit you want to use.
Other Information on Impact Drivers
How to Use an Impact Driver
The usage of impact drivers is not much different from that of an electric screwdriver. As with most electric screwdrivers, many of them are rechargeable. Therefore, the battery must be fully charged before use.
When working, replace the bit on the end of the screwdriver to match the screw to be tightened, align it firmly with the screw thread, and pull the trigger. Depending on the product, the rotation speed can be changed. Some products allow the rotation speed to be changed depending on the strength of the trigger, while others allow the speed to be selected in advance using a button. Many products also allow the direction of rotation to be changed with a push button.