Yet another Thread thread - UTS Implementation

[TomD.inPDX]

I just wanted to post a a little helper file for creating internal and external threads based on the Unified Thread Standard (UTS) which covers both English and Metric.

I must give high kudos' to Wikipedia.  I borrowed their images and tables for the attached Creo 2.0 full version parametric file.  You will also find a linked link in the site if you turn on annotation.

See the relations to drive the pitch and diameter you are interested in.  The file is set up for English but you can change it to metric units, if that is your primary usage.  Most everything that can be driven by relations has been.  Only 3 variables are needed... and TPI (thread per inch) is set to zero if you want to define the pitch directly for metric threads.  See the "IF" statement in Relations.

I did have some troubles along the way.  I split up the helical sweep because it -did- fail if I did it in one go although it did not overlap anywhere.  This was customer support's "works as expected" Pro|WorkAround© for helical sweeps that fail otherwise.  This made the file more robust for changing threads on the fly through relations.

Of course, I suggest you make a library part of the two sketches in the file and use them liberally.  Otherwise, the file is a nice quick reference for many thread features.  And if you link into Wikipedia, you will find even more excellent information about this standard.

http://en.wikipedia.org/wiki/Unified_Thread_Standard

http://en.wikipedia.org/wiki/ISO_metric_screw_thread

Here are some of the highlight images from the file... turn off planes and CS' and turn on Annotation, Axes, and Points. 

The images should be saved in the file so no external reference issues should exist.

These are the actual "thread cutters"...

This is the structure of the file...

And I love intelligent parametric sketches...  yes, I have the rounding turned off on purpose.

If you find a serious bug, let me know.  Otherwise, enjoy!

[TomD.inPDX]

I had another occasion to model the threads in a set of models.

I created a new pair or thread sections attached to the original post.

They are universal, but I opted for  a default size of 1/4-20 UNC for both.

Note that these are primarily for on-the-fly thread cutting using the UNS standard applicable to both metric and imperial threads.  There are reference dimensions in both for driving other features to make the model easy to change if a thread change is required.

The nice thing about this process is that you can rough in all the features and once the helical thread is defined, go back and drive everything from a single sketch including lead-in chamfer, internal thread hole ID or external thread boss OD; even cosmetic threads as a backup if needed.

This also becomes useful in 3D printing.  Since the standard is line-2-line, consider fudging the major diameter to gain clearance.

Here is a video on their use.

[rubenvillarreal]

Antonius,

Hello there! I saw that you answered such a beautiful question, could you please upload these files using the Student Version of Creo? I'm using that version and I can't open the files attached to this document.

Thank you in advanced.

[TomD.inPDX]

I wish I could.  I do not have access to the academic version.

[rubenvillarreal]

Don't worry then!

I saw the video but the problem with the academic version is that the palette doesn't include the internal thread section that you copied.

Thanks anyway.

[TomD.inPDX]

True, I created and added the sections to the palette.

[ChrisPLM]

Hello Antonius,

thank you for taking time for sharing such useful tutorial.

Best regards

[rubenvillarreal]

This is great, years and I will keep returning here. One of the most helpful post for Creo. I even remembered the name! Another thread threads!

[RL_9388010]

Hi! This looks awesome. Could this easily be modified for NPT?