Pipe Threading

A few notes:
- the taper on a pipe is 3/4" per foot. For a 1/2" pipe, that's only about 0.030" in diameter change over about 1/2". So it's really important to be accurate when setting up your lathe, or the thread won't be right. There's an input parameter for Tip Radius. If you're having trouble with loose fits, increase this a bit. It makes a big difference, since it makes the cut 2 x Tip Radius larger.

- I had a lot of trouble with a hesitation between the effective thread and the vanish thread, which could be somewhat compensated for by threading at less than 100 RPM. There's a long thread about the cause of this at

https://forum.linuxcnc.org/20-g-code/-hesitation-between-two-consecutive-g33-codes?limitstart=0

if you're interested. In any case, include this code in your .INI file:

[TRAJ]
   ARC_BLEND_ENABLE=0

The code includes some notes. You may have to change initialization parameters, feeds and speeds starting at line 88 for your lathe. My lathe does not have speed control, but does have a spindle encoder that I use to cut threads. There's also a check to see that you're not using Tool 0 starting at line 21. This is mostly to remind me to set up the correct tool before I start.

File Attachment:

File Name:
File Size:5 KB

File Name: npt_pipe.ngc File Size:5 KB

For more CNC pipe threading machineinformation, please contact us. We will provide professional answers.

Here's a routine for pipe threading. I'm kind of lazy, so I wrote it where ordinarily all you have to input is the nominal pipe size to use it. Everything else should be OK as is. You can also input the actual pipe size and TPI from Machinery's handbook if you want. For instance, 1/2" pipe is 0.840 OD and 14 TPI.A few notes:- the taper on a pipe is 3/4" per foot. For a 1/2" pipe, that's only about 0.030" in diameter change over about 1/2". So it's really important to be accurate when setting up your lathe, or the thread won't be right. There's an input parameter for Tip Radius. If you're having trouble with loose fits, increase this a bit. It makes a big difference, since it makes the cut 2 x Tip Radius larger.- I had a lot of trouble with a hesitation between the effective thread and the vanish thread, which could be somewhat compensated for by threading at less than 100 RPM. There's a long thread about the cause of this atif you're interested. In any case, include this code in your .INI file:The code includes some notes. You may have to change initialization parameters, feeds and speeds starting at line 88 for your lathe. My lathe does not have speed control, but does have a spindle encoder that I use to cut threads. There's also a check to see that you're not using Tool 0 starting at line 21. This is mostly to remind me to set up the correct tool before I start.

Check out the answers to the top 11 questions that we received during a recent Q&A session on thread milling.

Thread milling, a popular feature request from CNC shops, was introduced in BobCAD-CAM V29 and BobCAM for SOLIDWORKS&#; V6. This feature makes machining threads easier than ever &#; allowing you to machine tapered (pipe) threads, supporting thread side roughing and offering machine compensation support.

 

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As a completely new feature, we want to make sure you understand everything you can do with it. So we fielded a bunch of questions about thread milling from CNC machinists and put Al DePoalo, the voice of BobCAD AfterDark videos, on the case to provide the answers.
 

1) What kind of thread milling is supported in BobCAD-CAM?

Inside threads
Outside threads
Straight wall threads
Tapered wall threads
Single start threads
Multi-start threads

 

2) What kind of tools are supported?

Single point
Multi-tooth

 

3) What are the advantages of single point tools?

Tooling is less expensive
One tool can be used for different pitches
They can be used for off-size holes
 

4) What are the advantages of multi-tooth tools?

Faster cycle times
Great for production
Preferred for most applications
 

5) Does BobCAD-CAM have a thread library?

Yes, BobCAD-CAM&#;s thread library comes pre-loaded with 10 thread types and over 200 sizes.

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If you want to learn more, please visit our website CNC pipe threading lathe.

Thread library options include: Thread Type, Major Diameter, Pitch, Minor Diameter, Taper Angle and Thread Angle

Thread types include:
Unified Fine UNF
Unified Coarse UNC
National Pipe Taper NPT
National Pipe Straight NPS
Metric Fine MF
Metric Coarse MC
British Standard Whitworth BSW
British Standard Pipe BSP
British Standard Fine BSF
British Association BA

Don&#;t see a thread size that you work with? No problem, users can edit and add as many thread types as needed.

 

6) Are there options to prep the hole before threading?

Using DMS in combination with our thread milling feature, you have many options to prepare the hole for threads. You can select from 8 machining cycles that include drilling and milling.

 

7) I thread mill regularly, are there any tools that can speed things up for me?

Yes &#; use the save and load feature to build a library of thread milling cycles that are fully defined and ready to use. The tools, speeds and feeds, and how you prep the hole can all be stored with the thread milling feature.
 

8) What about thread milling multiple locations? Is that supported?

Definitely &#; you can pick point locations, or a group of circles that represent your threaded holes / bosses.
 

9) What if they are on a different level of the part? Can you do that too?

Yes &#; using the hole groups, you can program thread mill cycles that start and end at different locations all in one feature.

 

10) My machine uses helical motion. Is that supported?

Yes &#; you can post your thread mill cycle using linear moves or helical moves. It all depends on what your machine supports. You pick the option that works best for you.
 

11) Are there any benefits of thread milling vs. tapping?

Yes &#; there are many, but it really depends on the type of work you do in your shop.

With thread milling, you&#;re able to use the same tool on different diameters &#; which cuts back on tool changes &#; and the number of tools you need to keep in stock.

Thread milling also requires less tool pressure than tapping &#; resulting in less tool breakage. But, let&#;s face it &#; if you overload a thread mill, it&#;ll break too &#; especially when working with small holes. So to help with that, thread milling gives you a side roughing option that lets you &#;walk&#; the tool into the wall.
 

Do you do any thread milling?

Give BobCAD-CAM a try and see how easy thread milling can be.

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