How to tap correctly? Our tips and tricks

# How to tap correctly? Our tips and tricks

Tapping is an essential technique in machining that involves creating internal threads in a pre-drilled hole. This prepares the holes to receive screws or bolts, ensuring a strong and accurate assembly of the components. While it may seem like a simple task, tapping requires careful attention to detail and an understanding of proper techniques to avoid common mistakes and achieve optimal results. This article explores the steps of tapping, the tools needed, and tips and tricks for doing it correctly.

# What is tapping ?

Tapping is a cutting process that creates internal threads in a hole. It requires the use of a specific tool called a tap, which is a cylindrical steel rod with helical splines that cut the threads in the walls of the hole. There are several types of taps, each designed for specific applications, such as hand taps, machine taps, helical taps, and upsetting taps. Before starting tapping, it is crucial to ensure that the hole has been drilled to the correct diameter. A hole that is too small will make tapping difficult and can cause the tap to break, while a hole that is too large will produce poor quality threads. Using a drill bit of the proper diameter is essential to ensure the accuracy of the threads.

# The main stages of tapping

The first step in tapping is to drill a pilot hole of the appropriate size. Choosing the diameter of the drill bit is crucial, as it should match the size of the tap and the type of thread you want to create. To determine the correct size of the pilot hole, it is recommended to refer to the correspondence tables that indicate the drilling diameter as a function of the diameter and thread pitch.

Once the pilot hole is drilled, it's time to prepare the tapping tool. For manual tapping, you will need a tapping wrench to hold and rotate the tap. Insert the tap into the wrench and make sure it is secure. Apply a suitable lubricant to the tap and into the hole to facilitate cutting and reduce friction. Lubricants play a crucial role in reducing tool wear and improving thread quality.

To begin tapping, insert the tap into the hole and gently turn it clockwise. It is important to keep the tap straight to avoid creating uneven threads or breaking the tool. After a few turns, you will feel the tap start to cut the fillets. It is crucial to proceed slowly and not to force the tap. After making a few turns, turn the tap slightly in the opposite direction to break and evacuate the chips, then continue tapping.

When the tapping is complete, remove the tap from the hole by turning it counterclockwise. Clean the fillets with a brush to remove any remaining chips. Check the quality of the threads by inserting a suitable screw or bolt to ensure that they engage properly and smoothly.

# TIVOLY tips and tricks for successful tapping

To achieve optimal results when tapping, it is essential to follow some best practices. First of all, the use of appropriate lubricants is crucial. Lubricants reduce friction, make cutting easier and extend the life of taps. The most commonly used lubricants for tapping are cutting oils, specialty greases, and cutting fluids. Be sure to apply the lubricant liberally to the tap and into the hole before starting the operation.

Next, it is important to maintain a constant and moderate pressure during tapping. Excessive pressure can cause the tap to break, while insufficient pressure can result in poor quality threads. Turn the tap slowly and steadily, pausing frequently to remove the chips. This technique helps prevent chip buildup, which can cause blockages and damage to threads.

Regular sharpening of taps is also crucial to ensure optimal performance. Dull taps require more force to cut, which increases the risk of breakage and reduces the quality of the threads. Use a proper sharpening tool to keep the sharp edges of the taps in good condition. It is also recommended to store taps in a dry and clean place to prevent corrosion and premature wear.

Choosing the right type of tap is also essential for successful tapping. Hand taps are ideal for small batches and fine adjustments, while machine taps are designed for mass production operations. Spiral taps are particularly effective for materials with long chips, as they facilitate chip evacuation. Set taps, on the other hand, are used for malleable materials, as they form the threads by plastic deformation rather than cutting.

# Common mistakes to avoid

Tapping is a delicate operation that requires careful attention to detail. There are several common mistakes that can compromise thread quality and damage taps. One of the most common mistakes is using an incorrect diameter drill bit for the pilot hole. A hole that is too small will make tapping difficult and can cause the tap to break, while a hole that is too large will produce poor quality threads. It is essential to refer to the correspondence tables to choose the right drill diameter.

Another common mistake is applying excessive pressure during tapping. Forcing the tap can cause the tool to break and damage the threads. It is important to maintain a moderate and constant pressure, turning the tap slowly and steadily.

Additionally, not using the proper lubricant can increase friction and wear on the taps, reducing their efficiency and lifespan.
Finally, not flushing chips regularly during tapping can cause blockages and damage to threads. It is recommended to turn the tap slightly in the opposite direction every few rotations to break and evacuate the chips. This technique keeps the sharp edges of the tap in good condition and ensures a clean and precise cut.

# Recent innovations and future trends

Tapping has benefited from several recent innovations that have improved the accuracy and efficiency of this operation. The use of tungsten carbide taps, for example, offers superior hardness and wear resistance, making it possible to make high-quality threads in hard and abrasive materials. In addition, special coatings, such as titanium nitride, reduce friction and extend the life of the taps.

The integration of robotics and CNC (computer numerical control) machines has also revolutionized tapping. CNC machines allow precise control of cutting parameters, ensuring consistent, high-quality results. In addition, automation reduces the need for human intervention, minimizing errors and increasing production efficiency.

Another notable development is the use of simulation software to optimize the tapping process. This software helps model and predict the performance of taps under different conditions, helping manufacturers choose the best tools and parameters for each application. This reduces trial and error, saving time and resources.

Tapping is an essential operation for the creation of internal threads in pre-drilled holes, ensuring a strong and precise assembly of components. By following best practices, using the right tools and applying appropriate techniques, it is possible to make high-quality fillets, reducing errors and increasing production efficiency. With recent innovations and technological advancements, tapping has become more accurate and reliable, allowing industries to produce high-quality parts with tight tolerances.

In summary, for successful tapping, it is crucial to choose the right type of tap for the material and application, ensure that the pilot hole is the right size, use appropriate lubricants, maintain constant and moderate pressure, and regularly discharge chips. By avoiding common mistakes and adopting best practices, thread quality can be improved and tap life can be extended, contributing to more efficient and cost-effective production.