The number of fasteners needed in a commercial aircraft can range from one to three million, depending on the make or model.
Much has been said about the importance of fasteners in the aerospace industry, and rightly so. Each one is needed to keep an aircraft intact under the extreme conditions of flight. Thereby, the tools used to tighten these fasteners are also essential.
In this article, we will focus on the less-heralded fasteners, discuss the types and characteristics of screws, and the best options for the air-powered screwdriver.
Some parts of the aircraft require frequent removal for maintenance or replacement on which rivets would be disadvantageous. Other parts need higher strength and rigidity at the joint that the rivet could not satisfy. In these instances, threaded fasteners such as the screw are used instead.
The screw is similar to the bolt in that it also has a head at one end and a threaded shank at the other. While the threaded tip of the screw can be either blunt or pointed, the bolt's is always blunt. The threaded end of the screw can be fitted with a nut, other types of a locking mechanism, or screwed directly into the aircraft part, whereas the threaded end of the bolt can only accommodate the nut. Another basic but important difference between the two types of fasteners is that the screw is turned on its head while tightening, but in a bolt assembly, the nut is turned instead of the head.
Among the threaded fasteners used in the aircraft, screws are the most commonly used. The following are the types of screws that can be seen in the aircraft assembly.
As its name implies, this type of screws is used to connect structural parts of the aircraft together. They are made of alloy steel, which is heat-treated for added stability against tensile and shear loads. They have a defined grip length and a similar load capacity as a bolt of the same size. Its appearance can be differentiated from a bolt through its head, which can be round, countersunk, or brazier type. The recessed head type can be driven by either the slotted or Phillips screwdriver.
This type of screw is used for general applications in the aircraft assembly with lower load requirements. It is commonly made from low carbon steel, aluminum alloy, or brass. It can be classified further into many different types according to the shape of its head. The flush-head goes into countersunk holes where a smooth finish is needed to reduce aerodynamic drag. The round-head is used to join higher-stress aircraft parts. The fillister-head is used for light applications. The other two types are the socket head, which is screwed by internal wrenching, and the pan-and-truss head, which is used where head height is not critical.
A self-tapping screw makes its own thread as it is being driven into a pre-drilled hole and can only be used on relatively soft materials. It is useful in the permanent assembly of nonstructural components, attaching removable parts, or temporarily holding parts together in preparation for riveting.
Even though screws account for only 20% of all fasteners used in aircraft assembly, this is still a considerable number given the millions of fasteners each aircraft requires. To have a viable product supply chain, productivity must be optimized every step of the way. In the assembly stage, operator productivity can be vastly improved with the right tools in your assembly line.
Every effort must be made to keep up with increasing demands and soaring production costs of an aircraft. In tool design, it means building durable air-powered screwdrivers with enough speed, torque repeatability, and ergonomic advantages to help the operator do more with less time.
The following air-powered screwdrivers are some of your best options to speed up your production:
LTV Small Angle Air-powered Screwdrivers - This is one of the smallest air-powered angle screwdrivers in the market today. Additionally, its angle head has a slim design, making it ideal for working in cramped spaces where neither a pistol grip nor a straight grip tool can fit. It has a spiral cut gear for less play and more accuracy.
LUD Pistol Air-powered Screwdriver - This is the perfect tool for self-tapping screws. Its torque level can be adjusted by regulating the air pressure, and it has a direct drive that shuts off when the final torque is reached. It can be used with a high-grip if more feed force is needed or a low-grip for minimal reaction force.
LUM Pistol Air-powered Screwdrivers - This tool provides accurate tightening every single time regardless of joint stiffness variations, making it suitable for jobs that require high torque accuracy.
LUM Straight Air-powered Screwdrivers - This tool is built for a tough environment and is considered a workhorse among air-powered screwdrivers. Working all day with its superior ergonomic design and durability is simple and comfortable. It also comes in either a push-start or lever-start model, both of which are reversible.
S23 PRO Direct Drive Air-powered Screwdrivers - This tool has a soft start trigger for a well-balanced, smooth, and quiet operation. It is well suited for self-tapping and wood screws.
S23 PRO Slip-clutch Air-powered Screwdrivers - This tool is suitable for soft joints and in turning self-tapping, wood, or sheet metal screws. It emits an implied pulsating force once the desired torque level is achieved. It also gives the option between trigger or push-start for pistol grip models and lever or push-start for straight models.
S24 PRO Impact Drive Air-powered Screwdrivers - This tool is the perfect blend of operator comfort and product performance. It is lightweight but powerful with its unique impact mechanism, raising productivity to a whole new level. It comes in two models, and both are reversible.
S24 PRO Shut-off Air-powered Screwdrivers - This tool has a fast shut-off function and an adjustable torque setting that can deliver smooth performance and highly accurate tightening. It is engineered for accuracy and durability to meet all the demands of industrial use.
Twist 12/22 Air-powered Screwdrivers - This line is equipped with a spring-operated slip clutch that emits a pulsating force when the desired torque level is met. It is suitable for applications where the torque level may temporarily rise during the rundown phase.
It is essential to find the current best method and apply it to every product without fail. In aerospace, using tools with high durability and repeatability is key in producing consistent results, especially in aircraft assembly with its millions of fasteners. Atlas Copco's wide range of high-accuracy and ergonomic pneumatic screwdrivers can boost operator productivity, speed up your production, and help you meet other cost demands of the aerospace industry.
Contact us now for a free quote of our high-performing aerospace tools.
1. Akbiyik, Akin, Fasteners in the Aerospace Industry: Aerospace Fastener Applications, Part 1 Lecture Notes, Academia
2. Aircraft Hardware Chapter 6, navybmr
3. Aircraft Hardware – Rivets and Fasteners (Part Seven), Flight Mechanic, 2017
4. Durham, Bryce, Determining Appropriate Levels of Robotic Automation in Commercial Aircraft Nacelle Assembly, dspace.mit.edu, June 2014