How to Use a Tap and Die Set

Summary

In this workshop, the host delves into the basics of tap and die sets, essential for creating and repairing threads on bolts and rods. They explain the difference between taps for internal threads and dies for external ones, highlighting the SAE and metric systems. The importance of using lubricants like 'Rapid Tap' is stressed, along with the necessity of knowing the correct hole size for threading. Practical demonstrations include cleaning a 7/16 bolt with a die, cutting new threads on a rod, and the use of a thread gauge and chart for accuracy. Tips for using taps, like starting with a smaller drill bit and the advantage of a one horsepower bench grinder, are shared to ensure success in DIY projects.

Takeaways

• 🔧 The video discusses tap and die sets, essential tools for creating and cleaning internal and external threads.
• 📏 It differentiates between a tap, used for internal threads, and a die, used for external threads.
• 🇺🇸 In the U.S., threads are measured in threads per inch (TPI), with SAE threads being either fine or coarse.
• 📏 A 7/16 inch wide bolt with fine threads has 20 TPI, while a coarse version would have 14 TPI.
• 📏 Metric bolts measure thread size differently, by the distance across the top of the threads.
• 🔩 A thread gauge is a useful tool for confirming the correct thread size, such as ensuring a 7/16 fine bolt has 20 TPI.
• 📊 Thread charts are helpful for determining the correct number of threads per bolt and the appropriate drill size for tapping.
• 🇬🇧 Whitworth or BSF British Standard Fine threads are an older standard still found in some older cars and require special taps and dies.
• 💧 The use of lubricants like 'Rapid Tap' is crucial when using taps and dies to reduce friction and prolong tool life.
• 🛠️ When tapping a hole, it's important to drill to the inside diameter (ID) of the bolt, not the outside diameter (OD).
• ⚙️ The video demonstrates the practical use of taps and dies, including cleaning threads, cutting new threads, and the importance of using the correct hole size.

Q & A

What is the primary purpose of a tap and die set?

A tap and die set is used for creating and repairing threads. A tap is used to create internal threads, while a die is used to create or clean external threads.

What is the difference between SAE and metric threads?

SAE threads are measured by threads per inch, while metric threads are measured by the distance across the top of the threads.

What is a thread gauge used for?

A thread gauge is used to measure the number of threads per inch on a bolt to ensure it matches the standard for that size.

Why is it important to use lubricant when using taps and dies?

Lubricant, such as Rapid Tap, is important to use when working with taps and dies as it reduces friction, prevents tool breakage, and extends the life of the tools.

What is the significance of the beveled edge on a bolt?

The beveled edge on a bolt is designed to make it easier to start the nut, reducing the force needed to initiate threading.

How does one determine the correct hole size for tapping?

The correct hole size for tapping is determined by using a chart that specifies the appropriate drill size for the given tap size, ensuring the internal diameter of the hole matches the bolt's internal thread size.

What is the difference between a standard tap and a bottoming tap?

A standard tap, also known as a plug tap, does not go all the way to the bottom of a hole, whereas a bottoming tap is designed to reach the bottom of a hole, allowing a bolt to be fully inserted into a solid piece of metal.

Why is it recommended to start with a smaller drill bit when drilling for tapping?

Starting with a smaller drill bit and gradually increasing the size is easier on the driller and the equipment, reducing the risk of breakage and ensuring a more precise hole size for the tap.

What is the purpose of a thread chaser?

A thread chaser is used to clean and reform threads, especially useful for minimally damaged bolts or when cleaning up external threads.

Why is it important to back the die or tap out after each turn when threading?

Backing the die or tap out after each turn helps to break and clear away metal chips, reducing resistance and preventing the tool from jamming or breaking.