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Tapped holes are created using the tapping method. But, threaded holes can be created using several methods, including tapping, milling, forming, etc. Besides, a tapping hole is ideal for soft material, whereas a threaded hole compliments best with harder materials.
To explore more differences, keep reading:
What Is a Tapped Hole?
Tapped holes are holes that have internet threads allowing screws and bolts to fit securely. The threads inside the holes are made by using a tool called a tap. This ensures a tight connection of the fasteners.
Tapped holes are of two types; these are:
a. Through Tapped Holes
Through tapped holes, it passes completely through the material, creating an opening on the other side. This allows the screws to insert at the end of the material and emerge from the other end. These categories of tapped holes are ideal for joining multiple parts together.
b. Blind Holes
Blind holes do not go throughout the material. Instead, they pass a specific depth and keep the bottom hole enclosed. These tapped holes are suitable for applications that require a finished and neat surface without letting the tapped hole emerge from the other end of the surface.
Image: Through tapped holes vs blind tapped holes
Characteristics and Features Of Tapped Hole
- Created through the tapping process
- Requires pre-drilled holes
- Suitable for congested space or location that offers access to only one side
- No need for nuts
- Provides a durable and robust connection between parts
Pros Of Tapped Hole
- Suitable for application with space limitation
- Provides a secure and robust connection
- Compatible with a wide range of material
- Customizable thread size, depth, and pitch
Cons Of Tapped Hole
- High precision is needed for accuracy
- Tapping is not suitable for soft and brittle material
- Time-consuming process
- Thread incompatibility affects the stability of the joint
What Is a Threaded Hole?
Threaded holes refer to any holes in general that have internal threading. It doesn’t matter which process is used in creating the threads inside the hole; it can be made using milling, tapping, or forming.
Characteristics and Features Of Threaded Hole
- Created by tapping, milling, or other methods
- The robustness depends on the material, and threads’ depth. Depper thread provides stronger connections.
- Requires high precision for reliable fastening
Pros Of Threaded Hole
- Multiple disassembling and reassembling is possible
- One-side access is enough
- Provides robust connection
- Low tooling cost
Cons Of Threaded Hole
- Not suitable for all types of material
- Thread can wear down over time
- Less post-modification flexibility
Tapped Hole vs Threaded Hole: What Are The Differences?
Tools & Equipments
In tapped holes, threads are created using the tapping method. This involves tools and equipment like a tap tool, tap wrench, or tapping machine.
In contrast, threaded holes are created following different methods, including tapping, milling, and forming. So, different tools can be used here. Besides the use of tools similar to tapping, it can include die or special inserts for specific thread types.
Process Or Method Differences
The process of tapping holes is pretty simple; all you need to do is drill holes of appropriate measurement. Insert tap into the holes and rotate it until it reaches the desired depth and gets secure.
The threaded holes are created by creating a cylindrical surface on the metal, and then threaded patterns are cut internally or externally. This process deals with rolling or cutting threads in the surface mostly by using die tools. The most popular methods for creating threaded holes are as follows:
a. Cut Threading
A cutting tool is used to remove the material from the surface to create threaded patterns of the required design.
b. Roll Threading
In this method, high pressure is applied to the working material creating threads upon deformation. Roll threading is mostly used to enhance strength and is suitable for both internal and external threading holes.
Materials
As tapped holes need to deal with drilling, it is compatible with hard materials that have no risk of deformation upon direct threading. So, you should choose tapped holes for materials that can withstand the cutting or forming action, such as aluminum, brass, mild steel, and similar metals. However, using them on very hard material is also not suggested, as tapping can lead to tool wearing or breakage.
Threaded holes are suitable for varying materials, including steel, titanium, plastic, and more. You can also use tapped holes in softer or brittle materials.
Drilling Requirements
To create tapping holes, you must drill holes. Here you first need to drill holes to the required diameter and next insert taps to create internal threads. These threads facilitate the fasteners to secure within the material.
In threading, drilling is not always mandatory. You can use thread-formed screws or self-tapping screws that cancel the drilling requirement. These screws create threads when driven into the materials.
Quality Control
Quality controlling is essential for both tapped and threaded holes to ensure optimal result. However, threaded holes are a more complex process and need tiger control. This involves high-RPM milling and is used for permanent fasting. So, once fitted, refixing is challenging.
Tapped holes, in this case, require simple quality control. All you need to take care of is maintaining accurate thread depth, pitch, and alignment. Controlling these things is easy if you use precise tools and ensure accurate drilling.
Compatibility with Fasteners
Tapped holes are directly compatible with specific fasteners like screws and bolts. This ensures a secure connection as specific tapped holes are drilled for using specific fasteners.
Threaded holes on the other side are compatible with a wide range of fasteners. You can create threaded holes as per the fastener’s size and thread profile.
Strength and Durability
Threaded holes are widely used in heavy-duty application for its greater strength offering and durability. In contrast, a tapped hole is also reliable but it does not offer as much strength as threaded holes. Therefore, if you need a more robust connection for an industrial setting, threading holes is a better option than tapped holes.
Precision
Tapped holes are created using a specific process: tapping. So, if you can control tapping, you can achieve high precision in tapped holes. It provides tighter tolerance and is suitable for critical applications where accuracy is a priority.
Compared to tapped holes, threaded holes have looser tolerances, especially in harder material. Besides, here, the accuracy also depends on the method you use for creating the threads. Threaded inserts or molded threads may have looser tolerances compared to tapped threads in harder materials. It deals with the die or mold use of thread creating and the precision can vary depending on the use of tools.
Usage/Application
Tapped holes are commonly used in simple and regular applications that don’t need high strength. These are ideal for removable fasteners or applications that offer adjustment facilities. For example- assembling parts of furniture, medical devices, mounting brackets, etc.
The threaded hole is ideal for a complex application that demands permanent fastening of screws or bolts. For instance, you can use it in construction projects for permanent joints. Besides, threaded holes are suitable for machine coupling and offer permanent solutions for high-stress mechanical components.
Speed
Tapping is a straightforward process that drills with simple drilling and tap insertion. This makes the process relatively faster.
On the contrary, the speed of threaded holes depends on the possess used. If you are using a milling process for threaded holes, it will take more time. Besides, maintaining precision is also a fact that relates to its speed. However, for bulk production, you can automate the threading process to boost speed.
Efficiency
Tapping holes with forming taps can increase production efficiency many times. But this is more suitable for soft materials. And if you want maximal scaling, threading holes is definitely the better option.
The automated threading process allows you to create multiple holes of varying sizes using a single tool. You need not change the tool frequently for varying hole sizes. The machine will adjust it by itself. Thus, for industrial applications requiring varying threading types and hole sizes, threading holes are a better option than tapping for high efficiency.
Flexibility
Threading holes offer better flexibility as you can create varying thread sizes and profiles using a single tool. In this aspect, the flexibility in the tapping hole is limited. It is suitable for specific threaded sizes. However, where customization is a priority, threaded holes work best.
Cost
Tools for tapping are designed to create holes of definite hole sizes. That is, using a tool you can’t create a tapping hole of different sizes. For that, you will need different tools. This increases the leading cost for beginning variations in production.
In threading, a single tool can produce threaded holes of different sizes and types. You can also create internal and external threads as per your requirement using a single device. This reduces the initial cost by many times.
Tapped Hole Vs. Threaded Hole: Similarities and Limitations
Similarities
- Both tapped and threaded holes are used to accommodate fasteners like screws or bolts.
- They are widely used for a variety of applications like- manufacturing, assembling, construction, and more.
- Quality control is mandatory for both tapping and threading holes to maintain accuracy and proper connection with fasteners.
Limitations
- The material compatibility of tapped holes depends on their ability to withstand the cutting or drilling.
- Tapped holes are more suited for uniform applications and are limited to specific fastener sizes and holes.
- Threaded tools are more complex and require skill to work with.
- Tapped holes are less durable in soft material than threaded holes.
Tapped Hole Vs. Threaded Hole: Which One To Choose?
Whether to choose tapped holes or threaded holes depends on your application requirements.
When to choose tapped holes?
- For soft materials like aluminum or mild steel
- Simple, small to medium projects
- Low-budget and low-volume applications
- Removable, adjustable, and semi-permanent application
When to choose threaded holes?
- For harder materials like titanium, steel, or plastics
- Requiring a variety of thread types, sizes, or profiles
- Permanent and high-strength application
- Mass production
Conclusion
If you need to deal with a variety of thread types and hole sizes, threading holes is the best option. Using a single threading machine, you can create threaded holes of different sizes. Besides, it provides higher strength for harder material and is suitable for permanent fastening.
However, if you are looking for a simple solution, a tapping hole is good to go. These are ideal for small to medium projects that require part removal or semi-permanent joints. Therefore, consider your application’s demand to pick the right hole type.
FAQs
How to determine screw size from a hole?
To determine the size of a screw from a hole, you can implement either of the three methods- the alginate method, the vernier caliper method, or the size measurement scale method. In the first method, you will need to pour liquid alginate into the hole, and once it solidifies, it will form the shape of the screw. If you follow the Vernier caliper method, use the device to measure the diameter of the hole. Then, insert a stick or straw into the hole, mark the endpoint, and measure the length with the caliper. Or simply use a bolt scale on the hole to take measurements.
Is a tapped hole the same as a threaded hole?
A tapped hole is, in fact, one type of threaded hole. It is a process of creating internal threads using the tapping process. However, threading is a broader term and refers to all types of threaded holes, irrespective of the method used for thread creation.
How long should a threaded hole be?
The length of the threaded hole depends on the material you are working on. For example, in aluminum, the length of the threaded hole should be two times the nominal diameter. And if you are working on steel, it should be one time the nominal diameter.
What materials can you tap?
You can tap a variety of materials, including aluminum, brass, carbon steel, cast iron, copper, stainless steel, titanium, etc.
Can I tap holes using a power drill or drill press?
Yes, using a power drill or drill press you can tap holes with better precision than going freehand.
