Tapping en3b

B

benrighton85

Plastic

Joined

Sep 1, 2019

• Aug 1, 2021

• #1

Hi. I’m tapping some en3b bar. I’m have trouble with the threads breaking up. I have the pitch correct and drill size is fine. Is there anything special I should be doing? The program is a face off drill then tap. Tapping speed is 100rpm. When I tap with free cutting steel the thread are perfect. Thread size is m16. Thanks


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M

Milland

Diamond

Joined

Jul 6, 2006

Location

Hillsboro, New Hampshire

• Aug 1, 2021

• #2

What brand and type of tap are you using? What coolant or oil in the lathe?

You might try form tapping if you have the right lubricity of coolant/oil and sufficient torque from the lathe.

 

B

benrighton85

Plastic

Joined

Sep 1, 2019

• Aug 1, 2021

• #3

Hi. Not sure on the tap brand. It’s a spiral flute with just soluble cutting fluid. The lathes a mazak qt20 plenty of power.


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plastikdreams

Diamond

Joined

May 31, 2011

Location

upstate nj

• Aug 1, 2021

• #4

It's basically 1018 steel...what's the issue?

 

R

Red James

Stainless

Joined

Jan 26, 2013

Location

Plainfield, Indiana, USA

• Aug 1, 2021

• #5

Double you rpm ... somewhere near 220 RPM should help a bunch.

 

M

Milland

Diamond

Joined

Jul 6, 2006

Location

Hillsboro, New Hampshire

• Aug 1, 2021

• #6

Red James said:

Double you rpm ... somewhere near 220 RPM should help a bunch.

Click to expand...

I've had more trouble with spiral flute taps than any other. It's like the spiral leaves a weaker geometry and gives more opportunity for ship strings to get caught and bind (if they don't fully clear on the way in).

If he can form tap it'll save him a lot of issues - stronger tap, nicer threads, no chips at all.

 

B

benrighton85

Plastic

Joined

Sep 1, 2019

• Aug 3, 2021

• #7

plastikdreams said:

It's basically 1018 steel...what's the issue?

Click to expand...

The threads are breaking up


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M

Milland

Diamond

Joined

Jul 6, 2006

Location

Hillsboro, New Hampshire

• Aug 3, 2021

• #8

Coolant lubricity, tap design, bad stock, bad parameters.

Pick one. Or more...

 

B

benrighton85

Plastic

Joined

Sep 1, 2019

• Aug 3, 2021

• #9

Milland said:

Coolant lubricity, tap design, bad stock, bad parameters.

Pick one. Or more...

Click to expand...

Works fine on free cutting steel. Need a weldable steel hence the en3b. When you say bad parameters?? Any in particular?


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M

Milland

Diamond

Joined

Jul 6, 2006

Location

Hillsboro, New Hampshire

• Aug 3, 2021

• #10

Can you post pics of the tooling you're using? You said spiral flute taps, right? Have you tried form taps? And is the coolant at proper mixture?