What Is Bolt?
A bolt is an externally threaded fastener created for the insertion through holes in the assembled parts. Generally, bolts are intended to be released by nuts.
This Bolts in a uniform circular cross-section, the threads are spiral in structure and have a smaller pitch as compared to screws. These bolts don’t have tapered shanks, and the parts secured by bolts possess greater strength than parts secured by screws.
These bolts act on the application together with the nut and are tightened on the part in which the torque is applied. Some of the generally used bolts are plow bolts, carriage bolts, and track bolts. The reliability and durability of parts joined by bolts are much higher than those joined by screws.
Applications that use bolts include flange joints or fastening of objects made of metal materials. Moreover, bolts aren’t only used in machinery but also plumbing and electronics. Z Bolts are an integral part of equipment and component reliability.
Bolt Pretension
Bolt Preload – The tension created when the nut is screwed onto a bolt to hold two materials together.
When the tension reaches the optimal preload, the working load (load added after creating the assembly) placed on a bolt will be distributed into the installation materials, so the bolt does not take the entire load.
What Is Screws?
A screw may be defined as an inclined plane wrapped around a nail and characterized by a helical ridge. In other words, it is a long metal shaft with threads circling along its length. It also has a turning where a screwdriver can be used to rotate the screw.
A screw generally has a head with a specially formed shape. The shape determines and heads size the size of the tool to be used to turn or drive the screw. Commonly used tools are wrenches and screwdrivers.
The underside part of the head is a shank that can be fully or partially threaded. A screw thread is a structure on a coned or cylindrical shape in the form of a helix.
The top of the ridge is known as a crest and the bottom root. The distance between the crest of the one thread to the next one is known as a pitch.
Screws are tightened by rotating the tool anticlockwise or clockwise and are usually used for joining materials that don’t have existing holes in them.
The most common types of screws used in manufacturing are drywall screws, dowel screws, mirror screws, and concrete screws. The strength of a screw relies on the width of the thread and the distance between them.
However, the more numbers of the threads, the more rotations would be required to attach the screw. Also, if the continuous distance thread is wider, more force must be exerted on the tool in the rotations.
Screws are widely used in many applications. From motorcycles to furniture, from air conditioners to kid’s remote control cars.
Bolt Vs Screw
Difference between nolt and screw are as follows.
| Sr.No. | Bolt | Screw |
| 1 | Screws are tightened by rotating the tool clockwise and are usually used for joining materials that do not have existing holes in them. | A screw is an externally threaded fastener capable of being inserted into holes in assembled parts, of mating with a preformed internal thread or forming its own thread, and of being tightened or released by torquing the head. |
| 2 | Bolt is always used in pair like nut & Bolt | Screws are always used by itself. |
| 3 | Bolts are used with un-threaded components. | Screw can be used with threaded or un-threaded components. |
| 4 | In the bolt cross Uniform section | In screw can have non- uniform cross section |
| 5 | The threads are spiral in shape. | The threads are helical in shape. |
| 6 | It doesn’t have tapered shank. | It has tapered or pointed shank. |
| 7 | This Bolts mostly require wrenches and spanners for the tightening and loosening purposes. | This screw requires mostly screw drivers for the tightening and loosening purposes. |
| 8 | This bolt is reliable | Here, Screw is less reliable |
| 9 | Bolts are larger in size. | Screws are smaller than bolts. |
| 10 | Larger size bolts are used to achieve higher load-carrying capacity. | Screws are not available in very large size. They are generally used for low load carrying applications. |
| 11 | Bolt are always fixed at a single position with the use of a tool. | Screws has to be turned every time it has to be assembled. |
| 12 | They apply compression on the parts that they join. | They don’t apply compression on the parts that they join. |
| 13 | They are often used in the making of bolted joints. | They can’t be involved in the bolted joint making due to the presence of at least one thread. |
| 14 | The examples of bolts are Anchor bolt, T-head bolt, Toggle bolt, U-bolt, J-bolt, Eyebolts, Hexagon bolt/Tap bolt, Lag bolt, Machine bolt, Carriage bolt, Elevator bolt, Flange bolt, Hanger bolt, Plow bolt, Shoulder bolt, Square head bolt, Stud bolt, Timber bolt, etc. | The examples of screws are self-drilling, socket screw, eye lag, mating screw, Wood screw, machine screw, thread cutting machine screw, sheet metal screw, set screw, etc |
Frequently Asked Questions about Bolts and Screws
What is the main difference between bolts and screws?
Bolts are used with nuts and are typically used to fasten unthreaded components together, while screws are inserted directly into materials with or without pre-existing holes.
Can screws be used interchangeably with bolts?
No, screws and bolts serve different purposes and are not interchangeable. Bolts are designed to be used with nuts and require a wrench or spanner for tightening, while screws are typically tightened with a screwdriver directly into materials.
Which one is more reliable, bolts or screws?
Bolts are generally considered more reliable than screws because they apply compression on the parts they join, leading to stronger connections. Screws may be less reliable, especially in high-load applications.
What are some common applications of bolts?
Bolts are commonly used in machinery, plumbing, electronics, and construction for creating bolted joints. Examples of bolts include anchor bolts, carriage bolts, and flange bolts.
What are some common applications of screws?
Screws are widely used in various applications, including furniture assembly, automotive, electronics, and woodworking. Types of screws include wood screws, machine screws, and sheet metal screws.
How do bolts and screws differ in terms of size?
Bolts are typically larger in size compared to screws, and larger bolts are used to achieve higher load-carrying capacity. Screws are generally smaller and are not available in very large sizes.
Do bolts and screws require different tools for tightening?
Yes, bolts usually require wrenches or spanners for tightening, while screws are tightened using screwdrivers.
Can screws be used in bolted joint making?
No, screws cannot be used in bolted joint making due to the presence of at least one thread. Bolts are typically used in the making of bolted joints.
What factors determine the strength of screws?
The strength of screws depends on factors such as the width of the thread, the distance between threads, and the material composition. More threads and wider thread distances generally result in stronger screws.
Are bolts and screws both capable of applying compression on the parts they join?
No, only bolts apply compression on the parts they join, while screws do not typically apply compression.
