All About Tapping in Machining

What is Tapping?

Tapping is a way to make threads in holes. Threads help bolts and screws fit in holes. You need threads to put parts together.

Tapping is used in many jobs:

• Cars
• Planes
• Medical tools

The main tools you need for tapping are:

• Taps (the tool that cuts threads)
• Drill bits (to make the first hole)
• Holders (to keep the tap straight)

Types of Taps

There are many kinds of taps. You must pick the right one for your job.

Hand Taps

Hand taps are good because they:

• Don’t cost a lot
• Work for many jobs

But they can be bad because:

• You must line them up by hand
• This can make the tap break

Spiral Flute Taps

These are best for blind holes. Blind holes don’t go all the way through.

The spiral shape helps chips (tiny bits of metal) come out of the hole.

Thread-Forming Taps

These don’t cut the metal. They push the metal into a thread shape.

They work best with soft metals like:

• Aluminum
• Copper

The best part? They don’t make chips!

Pipe Taps

These make special threads for pipes. The threads get smaller at the end. This helps pipes not leak.

How to Tap: Step by Step

Before You Tap

1. Drill the right size hole
   • It should be about 85% of the thread size
   • Too big = weak threads
   • Too small = tap might break
2. Make sure the tap is lined up straight
   • If it’s not, it can break
   • Use a holder to help

While You Tap

1. Use the right oil or fluid
   • For steel: Use oil
   • For aluminum: Use a mix of water and oil
   • For cast iron: No oil needed
2. Turn at the right speed
   • Big taps = slow speed
   • Small taps = faster speed

After You Tap

1. Check if the threads are good
   • Use a tool called a thread gauge
   • It will tell you if your threads are right
2. Clean out all chips
   • Chips can make the bolt not fit right
   • They can also make the threads wear out fast

Top 5 Tapping Mistakes

Mistake 1: Wrong Tap Type

Problem: Using a machine tap by hand. Fix: Pick the right tap for your job.

Mistake 2: Chips Get Stuck

Problem: Chips fill up the hole and break the tap. Fix: Use spiral taps and pull out often to clear chips.

Mistake 3: Wrong Hole Size

Problem: Hole too small makes the tap break. Fix: Check a drill chart for the right size.

Mistake 4: Too Hot

Problem: Not enough oil makes the tap get too hot. Fix: Use more oil or special taps with oil holes.

Mistake 5: Old Taps

Problem: Old taps make rough threads. Fix: Check taps often and get new ones when needed.

Tapping vs. Thread Milling

How to pick:

• Lots of same holes? Use tapping.
• Hard metal? Use thread milling.
• Need to change thread size often? Use thread milling.

Tips for Tough Materials

Hard Steel

• Use taps made of carbide (very hard metal)
• Go slow
• Use lots of oil

Stainless Steel

• Use taps with special coatings
• These coatings help the tap slide better
• This means less heat and wear

Carbon Fiber and Other Mixes

• Use taps with diamond coating
• This stops the material from fraying
• It also makes the tap last longer

What The Numbers Show

Look at these facts about tapping:

• 60-75% of broken taps happen because the hole is the wrong size
• Using the right holder can cut breaks by 70%
• Good oil can make taps last 3 times longer
• Thread-forming taps can save $12,000 each year by not making chips

Real Stories

Plane Parts Company

Problem: Taps kept breaking in tough metal (Inconel 718).

Fix: Changed to carbide taps and cut speed in half.

Result: Taps lasted 3 times longer and no bad parts for 6 months.

Medical Tool Maker

Problem: Threads in titanium were getting stuck.

Fix: Used special oil and changed to thread milling.

Result: Made parts 80% faster and fixed less mistakes.

Car Factory

Problem: Threads were crossing in blind holes.

Fix: Started pulling the tap out often to clear chips.

Result: 95% fewer bad parts.

Common Questions

Tips For Success

1. Match the tap to your job
   • Think about the metal type
   • Think about how deep the hole is
   • Think about if it’s by hand or machine
2. Focus on these three things
   • Keep the tap straight
   • Use the right oil
   • Clear out chips often
3. Get training for hard jobs
   • Some materials are very hard to tap
   • Learning from others can save you time and money
   • Check out our guides on CNC threading for more help

Best Tools For The Job

When you need to tap threads in metal parts, pick the right tap:

• Aluminum: spiral point tap with oil
• Steel: TiN coated tap with lots of oil
• Stainless: Special coated tap with even more oil
• Plastic: Form tap with light oil

Remember that precision machining starts with good tools. The right tap can make your job much easier.

Final Thoughts

Tapping is a key skill in making parts that fit together. By picking the right tap, drilling the right size hole, and using the right oil, you can make perfect threads every time.

If you need help with complex threading jobs, check out our CNC thread milling services. Our team can help with hard materials and tight specs.

Remember: Good threads make good parts!