How to create NPT threads for printing?

douglas_whitted

Although I am a veteran CAD user, I have no access to paid CAD (ex. Solidworks), so I'm new to Onshape CAD and 3d printing. I'm disabled and trying to design and 3d print a adjustable straw for my wheelchair. I've gathered my design knowledge, which will use…

• 1/4PT Flexible Oil Coolant Pipe Hose
• Silicone Tubing

Now, I can design the adaptive part as needed, example my first will be a design to implement the straw by designing/printing a 'cola' cap usage. Below you'll find my Onshape CAD link where I created the custom bottle threads, which are functional with the bottle, but it printed only a hole, not NPT hole.

When using the hole function on Onshape, setting it to 1/4-18 NPT does printer (BambuLab A1 Mini) not print threads?

Thanks for all input

martin_kopplow

Try using the Feature Script "Thread Lab" instead of the hole feature. The built-in hole feature does not model the thread details, even though it has an option to create cosmetic threads for the purpose of visualization.

Derek_Van_Allen_BD

Thread Lab is an awesome feature but doesn't support tapered thread generation or the NPT spec. @EvanReese do you still have that doc handy for Amalgamation? I seem to have lost the link.

EvanReese

Yes it's here! https://cad.onshape.com/documents/b675b9d7712fc8ca1eefa8f6/w/e3f898db2bee36c1a5eaa5e5/e/b27953ec759731d7f0a5e203

Hats off to @rick_randall and @Oliver_Couch who put in a lot of effort and knowhow getting these models built and well configured. We intended to make it into a custom feature, at some point, but lost steam on it. These models can get new life as Amalgamate tools! Use the NPT Tap and NPT Die models.

rick_randall

A word to those interested in using the amalgamate models mentioned in @EvanReese post above - helps to think of the models as the tools that cut the threads, not the threads themselves. They must be subtracted from your model. I hope these tools will help someone. Cheers