The No-Fail Method For Tapping Holes With A Drill Press

Tapping with a drill press is a crucial skill for precision drilling and thread creation. By leveraging the power and accuracy of a drill press, you can effortlessly create internal threads in various materials, ranging from metals to plastics. This comprehensive guide will provide you with a step-by-step roadmap on how to tap with a drill press, ensuring you achieve optimal results.

Understanding the Process

Tapping involves using a cutting tool called a tap to create internal threads within a pre-drilled hole. The tap has a tapered design with cutting teeth that gradually remove material as it is rotated, forming the thread.

Selecting the Right Tap

The selection of the correct tap is essential for successful tapping. Factors to consider include:

• Material: Choose a tap specifically designed for the material being tapped.
• Thread Type: Determine the type of thread required (e.g., metric, imperial, standard, fine).
• Tap Size: Select a tap that corresponds to the desired thread diameter.

Preparing the Hole

Before tapping, the pre-drilled hole must be appropriately sized. The ideal hole size is slightly smaller than the tap diameter to ensure proper thread engagement. Refer to tap charts or manufacturers’ specifications for the recommended hole size.

Lubrication

Lubrication is crucial for reducing friction and heat during tapping. Apply a suitable cutting fluid or tapping compound to the tap and the hole. This will extend the life of the tap and improve the quality of the threads.

Setting Up the Drill Press

• Speed: Adjust the drill press speed according to the material and tap size.
• Depth: Set the drill press depth stop to prevent over-tapping.
• Chuck: Secure the tap in the drill press chuck using a tap holder or adapter.

Tapping Technique

• Alignment: Hold the tap perpendicular to the workpiece surface.
• Start Slowly: Engage the tap gently and gradually increase the speed.
• Reverse Rotation: Periodically reverse the drill press rotation to clear chips and prevent tap breakage.
• Monitor Progress: Check the thread depth and quality frequently to ensure accuracy.

Post-Tapping Inspection

Once tapping is complete, inspect the threads for any burrs or imperfections. Use a thread gauge to verify the thread pitch and diameter.

Troubleshooting Common Issues

• Tap Breakage: Incorrect speed, misalignment, or excessive force can cause tap breakage.
• Thread Stripping: Over-tapping or using a tap that is too large can strip the threads.
• Thread Binding: Poor lubrication or a damaged tap can cause thread binding.

Tips for Success

• Use a Sharp Tap: A dull tap will produce poor threads and increase the risk of breakage.
• Maintain Proper Speed: Excessive speed can damage the tap and the workpiece.
• Avoid Over-Tapping: Tapping too far can weaken the threads.
• Clean the Tap Regularly: Remove chips from the tap flutes to prevent clogging.
• Practice on Scrap Material: Before tapping on critical workpieces, practice on scrap material to develop your technique.

Answers to Your Most Common Questions

Q1. Can I tap with a regular drill?
A1. While it is possible, using a drill press provides greater control, accuracy, and safety.

Q2. What is the best material for taps?
A2. High-speed steel (HSS) is a common and affordable material for taps, offering a balance of durability and cost.

Q3. How often should I lubricate the tap?
A3. Lubricate the tap frequently, especially when tapping hard materials or deep holes.

Q4. What causes tap breakage?
A4. Incorrect speed, misalignment, excessive force, and dull taps are common causes of tap breakage.

Q5. How do I remove a broken tap?
A5. Use a tap extractor or reverse flute tap to carefully remove a broken tap.