Mastering the Art of Tapping: Everything You Need to Know About Threaded Holes

There is no dubiousness around the fact that tapping is one of the fundamental skills every person engaged in machining and manufacturing processes should possess. This blog post is intended to provide readers with comprehensive knowledge of threaded holes, beginning with their definition and classification through different tapping devices and methods and concluding with the most appropriate mechanical hand operations and practices. It further explains how the reader pursues this goal, whether as an experienced machinist or a novice in the profession. The reader will gain the skills and understanding necessary to efficiently attend to threaded holes with great confidence and much ease. Then, let’s get started and immerse ourselves into the world of tapping and its many subelements as related to machining.

What is the function of a Tapped Hole?

Explaining the concept of a Tapped Hole

Tapped holes, also called threaded holes, are holes that have been manually or machined to cut threads to enable the use of a screw or bolt. These internal threads are engaged with the external threads of the fastener, thus enabling the joint to be locked. Tapped holes are used in various sectors, including manufacturing, construction, and automotive, which require strong fastenings and assemblies. They facilitate the attachment of parts and are, therefore, very important to any reliable and strong connection. The most common type of tapped hole is produced by tapping, which involves using special tools to cut threads into the sides of the hole at a precise angle.

Comparison between Tapped Holes and Threaded Holes

Tapped holes and threaded holes are two terms that are often used interchangeably but are different facets in fastening and assembly. This is a relatively simple difference for people to understand:

• Tapped Holes: To place a matching screw, bolt, or stud into a tapped hole, the walls of said hole have been cut in such a way as to create threads that are necessary to make it possible for the fitting to work. The process of creating these walls is called tapping. Tapped holes are normally situated around the internal aspect of the bolt in question, enabling the fitting of an external bolt with matching qualities and size.
• Threaded Holes: Threaded holes can also be any such holes that possess threads, whether or not such holes have been formed by using a thread cutting tool, or any other type of device for that matter. Examples of threaded holes are the ones made on purpose during the making of certain objects or items that have a helicoil insert that provides threading features for additional holes created in which the features are needed.

To basically summarize what a tapped hole is, there is no simpler answer than – a hole where the walls have been cut with a tapping tool. A simplified threaded hole definition would be any created during the manufacturing of an object.

Common Uses of Tapped Hole

As a Technologist, I’ve noticed taps doing quite well across many industries due to their practicality. Common applications of tapped holes include:

1. Securely Fixing Parts: – For the bolts, screws or other add-on fasteners to be correctly added or secured, tapped holes are required.
2. Manufacture and Installations: This field excels at the necessity of assembling or disassembling other parts when the need arises for maintenance, repairs, or even upgrades.
3. Fixing positions of Parts: – The thread cut into the equipment can serve as a socket for other equipment, allowing the interconnections between machines to be made.
4. Routing conduits and cables: Tapping can be done through the holes created to install cables, pipes, or electrical conduits without messing up the entire installation.
5. Relative orientation of components: Proper orientation of tapped holes during the manufacturing processes assists the manufacturer in being accurate and repeatable.
6. Heliocoil Inserts: Inserts or mechanisms that enable multi-threaded holes were created in those holes to facilitate repeated assembly of components or parts.

In conclusion, tapped holes are an important factor across almost all industries, be it manufacturing or construction, as they allow fast assembly without pointless precision in many cases and interconnections of different parts or components in a wide array of engineering designs.

How Should You Go About Tapping a Hole?

Tools Required For Tapping

In order to tap a hole, there are a few tapping tools one would need to ensure that accurate dimensions are maintained. These tools include the following:

1. Tap: A tap is a tool that is used to make an internal thread in a hole that has already been drilled. Taps commonly have a head that is either square or hexagonal for grip, and a body that is fluted tapered or straight, which has the cutting edge.
2. Tap Handle: Tap handles help hold and turn the tap during the treading process. They also provide a firm grip, which allows for even more control when cutting threads.
3. Drill Bit: If you are going to tap, it is important to prepare a hole that is of the required dimensions. This can be done by using a drill bit. The drill bit must be in accordance with the size of the tap drill that is needed for the particular thread.
4. Cutting Fluid: Cutting fluid is especially useful in reducing friction and heat during tapping. It helps extend the life of the tap while ensuring even and smooth thread cutting.
5. Tap Wrench: In some situations, a small tap may be held in a wrench in order to prepare for tapping and the use of larger materials.

These essential devices interact aiding in the performance of the tapping processes, therefore the threads produced are properly formed according to the tapping requirements. These devices are sensitive and therefore require steady hands and the right procedures in order to render suitable results.

Avoiding Breakage of the Tap and Other Limitations

As a professional in drilling heads and threading parts, I am fully aware that there are some limitations to the tapping process, and among the most pressing is the issue of tap breakage. In order to avoid such issues in the future and enhance tap shafting procedures here are a few thoughts:

1. Material Selection: Many Factors should Be Considered When Choosing Suitable Taps, Which In This Case Are Material And Application. Other Considerations are the type of tap, which could be tapered, the bottom or plug, and the drill size, which is to be Taped. To slightly reduce the chances of breakage, they will ensure that the appropriate Sovereign taps are used.
2. Correct Spindle Rotation And Feed Speed Of The Progressing Taps: Measurement Of the Correct Quantity Of Spindle Turn Rate As Well As Feed Speed Of The Taps Progressing Is Extremely Important In Xy Loft. There Is No Breakage Of The Taps. This Must Be Achieved By Having a Starter Hole Of The Size Required And Matching Only The Minimum Cutting Speeds Of The Material Tapped At The Same Time Appropriate Feed, Rates Which Will Allow The Find Cut Chip Flow And Cutting Forces Combined.
3. Heat Permittivity And Joint Cooling: As A Cutting Fluid Or Lubricant Is Used For Tapping, These Are Permissively Required Using Suitable Cooling. It Reduces Friction Between The Material Being Cut But It Also Reduces The Heat Generated. This Allows The Cutting Tool To Last Longer While Reducing The Chance Of Tap Damage.
4. Proper Alignment and Stability: It is imperative to ensure the proper alignment and stability of the workpiece and the tap. Always properly attach the workpiece and employ appropriate clamps or fixtures where necessary to eliminate any movement during tapping. Improper alignment or lack of stability may cause the tap to break or thread quality to be poor.
5. Careful Chip Evacuation: Proper chip evacuation is an important consideration in tapping operations. Consider using peck tapping when deep holes are tapped or use spiral-pointed taps for through holes. Effective chip removal minimizes the chances of tap breakage and improves the threaded surface.

It is also very important to note that particular attention should be given to the above best practices to reduce the chances of a tap breakage and other related problems during the tapping process.

What are the different types of tapers and Tapers?

Comprehending Taper Taps and Their Applications

Taper Taps are cutting tools used to cut the internal threading within predrilled holes. Their conical shape means the angle extends from the tip to the end of the shank, which is the side that consumes more diameter. Due to this conical design, the tap is able to position itself accurately inside the hole and cut the necessary thread at a right angle.

Taper taps, especially M2, M3 or M4 are the first ones to create some form of a hole when a thread is started and putting secondary taps in place for ‘M’ sized threads where chipping could occur.

The bottom part of the tap, which goes into the internal threading hole, is also conical, which allows the chips to come out from the hole while cutting the thread. The more chips that come out of the hole, the less breakage of the tap and the better the thread that will be produced.

In case the tap is already a close fit within the internal threaded hole, it is necessary to spread some cutting lubricant to reduce heat during the process. Further, using peck tapping can prove to be beneficial if deep holes are required, because such processes effectively geese the chips out and increase the quality of the threading.

Grasping the functioning and appropriate application of taper taps can go a long way in ensuring that the tapping processes are efficient and effective, the likelihood of problems arising is reduced and the tap threaded holes that are created are of the high quality that is desired.

The Function of a Bottoming Tap for Blind Holes

Blind holes are those where the tap is supposed to reach right to the end of the hole. For such cases, a bottoming tap is ideal. While taper or plug taps have a tapered or semi-tapered part towards the lead, bottoming taps do not. They encompass a completely flat tip. This allows for near the tip of the cut hole to be threaded, thereby allowing the cut entire blind holes to be fully threaded.

Essentially bottoming taps are used for making threads towards the end of the blind holes which are not too deep. By using a bottoming tap, such as the one mentioned, one can fully thread such holes that allow for bolts or other tension fasteners to fit perfectly and tightly.

It is worth mentioning that bottoming taps do not have the capability of initiating threads in through holes or removing chips. They have been designed to work in blind holes. It must also be emphasized that optimal results can be expected from a bottoming tap only when a hole has been prepared to the required standards.

When to Use a Plug Tap

In the capacity of a machinist, plug taps find use in my work only in a few particular situations. Plug taps are also employed in the process of threading through holes, where plug taps are threaded in order to have a hole that goes all the way through the piece. Bottoming taps bolt into blind holes that have no entrance; plug taps are used to begin threads in through holes. They can also assist or improve chip removal during the tapping operation. However, it has been observed that plug taps do not make a threaded hole as dense or secure as a bottoming tap would do in a blind hole. This is why the threading requirements of your project should be analyzed, and the suitable thread tap be selected for the task at hand.

A Guide to Selecting the Appropriate Tap Drill Size for Your Work

Using a Tap Drill Chart

A tap drill chart is an important assisting diagram for machinists in identifying the right size of drill to use when tapping threads. It serves quite an elaborate function of combining the desired thread size with the recommended drill diameter. With the help of a tap drill chart, it is possible to determine the size of the hole that can be drilled for tapping without undermining the use of the desired thread. This chart factors in the pitch and classification of the thread, and gives table recommendations on the sizes of drill to use. A correct tap drill chart corresponding to the standard of the threads being used must be sought to conform to the necessary precision and accuracy while tapping.

Calculating the Correct Drill Size

It is obligatory to determine the right size of drill for tapping so that accurate and neat threads are produced on CNC machining operations. To determine the right drill size, one has to refer to a tap drill chart for the standard of the thread they are working on. Such charts incorporate thread pitch and class parameters to make accurate recommendations of the size of the drill to be used.

The correct drill size can be obtained by using a chart or by matching it with the desired thread size for tapping. This allows for the drilled hole to be an appropriate size when threading. A tap drill chart is necessary to ensure precision in your work.

If you have a particular class of screw-in thread standards, then the chart will guide you as to what size of drill bit s recommended using the thread pitch and the desired thread class. This will help to determine the correct size for the drill so as to get quality holes that will promote good work when the taps are in use.

In CNC Machining, it is wise to follow the thread standard’s dimensions by using taps and a reputable tap drill chart. This will help ensure that the tapping processes are accurate and precise.

Significance of Major Diameter and Hole Depth

Being a machinist, one should comprehend the notion of major diameter and hole depth in the procedures of tapping and threading with due regard when the size of a hole is expected. The major diameter, in this case, is the deepest cut of all so-called thread, which, in this case, decides the extent of fit and engagement of the threads. It serves to strengthen and effectively use the tapped hole internally. Likewise, Attention must also be paid to the hole depth, which is the depth of the hole that will be worked on to avoid thread engagement that is too deep with regard to tapping or threads that are not deep enough. This, in return, avails complete and secured connections by precisely defining major diameter and hole depth as it ensures the threads of the hole are formed in such a fashion as to perform their mandated tasks.

What Do You Need to Consider for Tapping and Threading in CNC Machining?

Set The Goals Right Before Starting CNC Tapping

When it comes to successfully carrying out CNC tapping operations, there are a number of factors that practitioners should focus on prior to the tapping process. These are both fundamental and integral to the success of the entire process. There are four of them mentioned and they include the following:

1. Workpiece Movement: In order to successfully execute the tapping operation, the workpiece needs to be restrained in a rigid position. This often requires the need to screw clamps or vise in order to fix the workpiece in place.
2. Tool Selection and Tools: Make sure to take an appropriate tap of the desired size and type which is suitable for the material being tapped. Also in order to improve the effectiveness of the tapping operation, the following aspects must be taken into account: The tap material, tap coating (if any), and the threading pitch.
3. Economics and Machine Features: The tapped hole must be in the correct dimension and orientation for correct thread engagement. When possible, combine tapped holes with suitable depth and location while using quality drill bits with sufficient size and appropriate point-drilled material. Ensure that the hole is completely clean of any loose particles that could potentially block the tapping operation from being carried out as anticipated.
4. Machining Operation: A flushing stream should be generated along the operation site. Choose the appropriate cutting fluid lubricant for the threading insert and the work material.
5. Machine Settings: You are required to appropriately adjust the spindle speed feed rate and depth of cut based on the tap size the material and the type of the thread needed. The proper calibration of the machine is a prerequisite for correctness of work pieces.

Through a good work ethic and focusing attention on the details at the preparation stage, operators can improve the CNC tapping process and achieve pleasing results.

Thread Cutting with CNC Machines Programming

When programming for thread-cutting within CNC machines there are quite several elements that need to be observed to achieve maximum productivity. First, I ensure that the tap size, workpiece dimension, and thread parameters are well defined. Efficiency is increased when such optimizations of spindle revolutions, feed rate, and depth of cut are determined. The machines are calibrated to minimize the effects of varying and unwanted factors on the thread cutoff. I see to it that optimal programming of the CNC machine takes place, producing good quality threads cut.

Tackling Blind Holes in a CNC Environment

In CNC environments, when working with the above-mentioned features, operators or machinists have other factors and procedures to take into account in order to perform the tasks successfully. The described features do not go through the entire workpiece, which can make the process of drilling and tapping somewhat difficult if not performed correctly. When adapting the CAD model to meet the CNC machines, the operator should note the following:

1. Choosing the Correct Tool: The effectiveness of the machining procedure for blind holes relies on the tools used. Using required drills and taps intended for such holes would facilitate the evacuation of chips and lessen required forces making it easier to fill upto the required limits.
2. Peck Drilling: A peck drilling strategy should be used to create blind holes. It comprises perforating the hole in varied, smaller measures and withdrawing the drill bit at times to unclog the barrel and curb chip packing. This approach aids in achieving excellent quality of the hole introduced and minimizing the potential for a particular tool to malfunction.
3. Coolant and Lubrication: The use of coolant or lubrication aids in cooling tools and workpieces during the drilling and tapping process while also minimizing the friction that applying force causes. It also aids in removing chips. This also helps in averting tool wear out, thus extending the working life of the tools.
4. Machining Parameters: It is vital to understand that operating parameters should be changed about the flute of the blind holes. The rotation of the spindle, the forwarding speed, and the extent of the portion should be modified to prevent the tool from being stressed while ensuring the proper formation of the chip and its removal.
5. Inspection and Verification: Once the blind hole has been drilled and tapped, it is important to check the workpiece where the hole has been made so as to ensure its conformity with the required standard in relation to quality and accuracy. This is done by using measured instruments like gauges or micrometers to check the drilled hole diameters, depth and the threaded hole requirements.

Considering these aspects and applying appropriate methods, machinists Should be able to deal effectively and reliably with blind holes in CNC environments while creating tapped holes that meet the required standards.

What Drill and Tap Tools Should a Machinist Use?

Essential Tap and Die Sets

Taps and dies are some of the most important tools for machinists since they allow them to cut internal and external threads, respectively. Below are some of the critical tap and die sets that every machinist needs to possess:

1. Metric Tap and Die Set: This set contains tap and dies for metric threads which are widely used across multiple industries. It contains several sizes and thread pitches for different uses.
2. Imperial Tap and Die Set: Whether you are working with imperial threads or inches, the imperial tap and die set is a must. It is quite extensive and comes in a variety of sizes and thread combinations.
3. Combination Tap and Die Set: A combination tap and die set includes both the taps and dies, which means there is no need to buy multiple sets. It is convenient and flexible, enabling users to perform sophisticated threading operations without having to purchase multiple sets.
4. High-Speed Steel (HSS) Tap and Die Set: Due to the demanding nature of high-speed machining, equipment and tools must be high-speed agnostic. They are manufactured from tough materials, which allows them to withstand harsh conditions, such as stainless steel and hardened alloys.
5. Adjustable Tap and Die Set: Finely adjustable tap and die sets come in handy while dealing with larger or unique screw threads. It enables machinists to cut taps and screws of any size by indeed altering the dies and the taps to the required requirements.

A skilled machine buyer will buy a quality tap and die set to thread holes and bolts in the required dimensions. Additionally, it makes it possible to operate effectively in CNC contexts and provide satisfactory outcomes.

The Role of Tap Handles and Drill Bits

In threading operations and various other machining processes, tap handles and drill bits play critical roles in ensuring accuracy and efficiency during the process. I, as a machinist, know for a fact that the outcome of the project highly relies on the tools used. Tap handles can make the process of tapping threads into the material easy by providing the right amount of torque needed to perform the action without wasting a lot of effort; furthermore, they protect the tap from misalignment and damage. Likewise, for the tap to be engaged accurately and centrally into the part, one or even better, two pilot holes might be drilled into the part first; this is where the tap guides come into play. Suppose machinists utilize the correct tap handles and drill bits specifically designed for the task. In that case, it will decrease the probability of wastage of time and preserve the tools during cutting operations.

Let’s explore which option is suitable for your purpose, which is cutting taps or forming taps.

Tapping can be difficult, and the finishing will depend on hand pressure when focusing on forming or cutting taps. Cracks and breaks in taps do happen when very high amounts of pressure are applied, and this is entirely manufactured.

Cutting taps, or thread-cutting taps as they are sometimes called, are equipped with sharp edges to cut and remove material from the inside of a workpiece as they are rotated into the material. These taps are designed to produce internal threads in metals, plastics, and wood. Cutting taps are quite accommodating and can work with almost any material and a variety of threads. They can, however, create chips within the tap, which requires more torque to operate.

On the other hand, there are Forming taps which are also specifically available, they cut the material in order to create threads due to the displacement of the material. They do not have flutes which are as pronounced as those on cutting taps, consequently they produce finer threads with a better finish. Forming taps Are, however, used on hard-to-machine materials such as stainless steel and hardened steel. Did you know they produce some of the best and most robust threads? It is important to note that they do take a lot longer to create them, and the amount of force needed is quite excessive as well.

When selecting either the cutting or forming taps, the machined surface and the wire cut feature of the tap should be the focus point, not the production. Therefore, it all comes down to what the manufacturer recommends and the specific application that was desired for the tapped and threaded holes: a reliable threaded hole made with either the cutting or forming taps.

Frequently Asked Questions (FAQs)

Q: What distinguishes a tapped hole from a threaded hole?

A: While the terms tapped hole and threaded hole are relatable, they can be used in a different context. A tapped hole is formed when a tap is used to cut a thread into an existing smooth hole, as according to a definition. On the other hand, a threaded hole refers to a hole having an internal thread, and it does not matter what type of operation is used to create the internal threads, cutting, tapping, or Thread milling, for example. Both types are classified into holes and are used for fitting bolts or screws into them.

Q: If a certain thread is specified,how do I select the correct tap drill size?

A: The amount of lift required on the tap size for the thread to be created depends on the diameter of the desired thread, as well as its pitch. In this case, use a tap and drill chart specification that relates recommended drill sizes to design threads. Using the correct tap drill size guarantees that enough material is left to be tapped, which prevents the threads from snapping or being too weak for standard use.

Q: What are the steps of the operation regarding drilling of a hole prior to the operation of tapping?

A: For drilling a hole before tapping, the following should be done – First, Take the tap size as a basis and pick the appropriate size drill bit. Second, Identify the approximate center of the hole. Third, Apply a Center Punch to establish a start point. Fourth, Clamp the workpiece to a drill press or vise. Fifth, Using the right method (Hand or machine), make the hole to the desired depth and position in relation to the surface. Lastly, Adjust to the needed thickness the hole to prevent the tap from wandering off center.

Q: What are the normal types of holes required for the tapping process?

A: The common types of holes used in tapping include through holes and blind holes. Through holes go all the way through the entire material while blind holes are tapered and do not cut entirely through the entire workpiece. So in a sense a blind hole gradually ends in depth rather than breaking through the surface of the entire workpiece. Special care needs to be taken in such operations so as to avoid the tap from causing breakage.

Q: How do I prevent breaking the tap during the tapping process?

A: In order to avoid breakage of the tap, consider taking these suggestions:1) Ensure correct size of the hole that the tap will be going into. 2) Cutting fluid should be applied to minimize friction. 3) The inserted tap should first be turned quarter forward, and then half turned back to allow chip breaking. 4) The tap should remain flat against the hole surface (normal position). 5) When working on tough materials, use a softer touch. 6) Remove the chips often. 7) If the part to be threaded is deep, it is best to use the series of taps (taper, plug, and then bottoming) one at a time until the threads are properly cut.

Q: What’s the difference between hand tapping and machine tapping?

A: Hand tapping involves the manual utilization of a tap and wrench in order to trace out threads on a given hole. It provides enhanced control especially when working on softer materials and fragile components. Machine tapping, on the other hand, employs the use of power tools or CNC machines to make threads, which leads to faster threading but, at the same time, less accuracy, especially if the threading needs to be very fine and lots of pre-threaded holes are needed and are made on simple materials.

Q: How do I prevent a tap from breaking when I use it at the bottom of a blind hole?

A: In order to tap the bottom of a blind hole without breaking the tap, follow the instructions below. 1) Measure the appropriate depth of the hole keeping in mind the volume of chips to be left behind at the hole’s bottom. 2) Utilize a bottom tap which has a small angle on the tip of the chamfer. 3) The first tap should be a taper tap to begin cutting the threads, followed by a plug tap. 4) Complete with a bottom tap, taking care not to apply excessive force that would push past the end of the hole. 5) At intervals, undo the tap to move chips and cutting liquid. Managing the blind hole taps appropriately helps avoid excess pour.

Q: What do you think are the notable benefits of a tread mill over tapping?

A: Thread milling, in comparison to tapping, has quite a few advantages, for instance: 1) Easier to tap threads with harder materials. 2) There is less danger of the tool being broken within the hole. 3) It is possible to manufacture drills for both right and left hand threads by using the same cutter. 4) It makes it easier to adjust the thread pitch diameter. 5) The torque applied on the workpiece is lesser. 6) Better for large-diameter holes. But one disadvantage of thread milling is that CNC machine is necessary; and it may seem to take longer than the tapping method when working with micro diameter holes.

Reference Sources

1. Numerical study on behaviour of T‐stubs with bolts in tapped holes
   • Authors: Marko Ptiček et al.
   • Publication Date: 2023-09-01
   • Citation Token: (Ptiček et al., 2023)
   • Summary: This study investigates the behavior of T-stubs connected with bolts in tapped holes, focusing on the influence of thread engagement length on the performance of bolted connections. The research includes analytical and finite element modeling (FEM) to validate the findings against experimental results.
   • Key Findings: The study provides insights into the minimum thread engagement lengths required for effective bolted connections, suggesting that optimizing these lengths can enhance the applicability of bolts in structural steel joints.
2. Experimental Analyses on the Resistance of Tapped Blind Holes
   • Authors: M. Kraus et al.
   • Publication Date: 2021-09-01
   • Citation Token: (Kraus et al., 2021)
   • Summary: This paper presents experimental analyses on the resistance of tapped blind holes used in bolted connections. The study examines how the depth of the tapped hole affects the connection’s load-bearing capacity.
   • Key Findings: The results indicate that the available screw-in depth of the blind hole significantly influences the structural behavior of bolted connections, emphasizing the need for proper design considerations in applications involving tapped holes.
3. High Precision Nut Threading Using Real-Time Tapping Torques Monitoring
   • Authors: Tsung-Chun Lin et al.
   • Publication Date: 2022-11-21
   • Citation Token: (Lin et al., 2022)
   • Summary: This research focuses on the tapping process for high-precision threaded nuts, utilizing real-time monitoring of tapping torques to ensure consistent quality. The study investigates the relationship between tapping parameters and the quality of the formed threads in tapped holes.
   • Key Findings: The findings demonstrate that real-time monitoring can significantly improve the quality assurance of threaded nuts, ensuring compliance with industry standards and reducing inspection times.
4. Finite Element Analysis of Tapped Thread Joints: Setup of a Computationally Efficient Modeling Approach
   • Authors: M. D. Agostinis et al.
   • Publication Date: 2019-11-15
   • Citation Token: (Agostinis et al., 2019)
   • Summary: This paper compares three-dimensional and one-dimensional modeling approaches to the finite element modeling of tapped thread joints. The study aims to optimize contact settings for accurate simulations of threaded connections.
   • Key Findings: The research identifies optimal contact settings that allow simplified models to replicate the results of more complex three-dimensional models, providing a more efficient approach for engineers designing threaded joints.
5. Structural Steel Joints with Bolts in Threaded Holes
   • Authors: Marko Pti et al.
   • Publication Date: 2022-08-15
   • Citation Token: (Pti et al., 2022)
   • Summary: This review paper discusses the application of bolts in threaded holes within structural steel joints, focusing on the advantages and challenges associated with this connection method. The study includes a parametric analysis of beam-to-tubular column joints.
   • Key Findings: The paper highlights the potential of using bolts in threaded holes to simplify construction processes while ensuring structural integrity, and it discusses the implications of thread engagement lengths on joint performance.
6. Tap and die
7. Screw