Modeling internal threads

[RustyG]

Does anyone have an easy way to model internal threads on solids?  External as well? Trying the sweep around a helix and it seems very finnicky. Any help appreciated. Thank you 

[crazy^millman]

It was answered on the official forum. Here is the response over there.

Quote

Making that way to hard.

Draw Helix. Make Triangle of Thread at Start of Helix normal to the start of the helix. Solid Sweep using The triangle at the sweep item and the helix as the sweep chain. Can remove when created as sweep from a solid and done. I like using a Center line for this since the 2019 release when this process changed.

Here is a 2024 file with 1″-8 thread removed from a simple solid block different threads. I put several different helixes on level one to learn from. Do not make the triangle bigger than the minor diameter. Notice my triangle is .001 small than what would be perfect overlap. Also don’t make the leg at the minor the same as a minor diameter of a thread you will get face errors when trying to remove. You can make the solid thread that way, but in a remove operation you need something not matching exactly.

Solid ID example

[JParis]

and as I Have said at least 100's of times......don't...

It uses copious amounts of system resources to visualize a thread.

When I import tooling that has threads, the very first thing I do is get rid of the thread.

File under, Just because you can doesn't mean you should.

JM2C YMMV

[crazy^millman]

I have made parts that have had specific features timed to threaded features like spray nozzles and other things. I agree with JParis 95% of the time I strip out all the threads to make the file lightweight. The 5% of the time I leave it for those picky customers that will refuse to run job if they don't see the threads in the setup sheets and Mastercam file. Yes they are some of the shops that have union employees. They can refuse to run a job if there is a spelling mistake or other things that have no bearing on setting up and running the job, but because they are looking for ways to not work and get paid no matter what they are looking for these things to justify their $65 to $70 hour pay.

[CEMENTHEAD]

18 hours ago, RustyG said:

Does anyone have an easy way to model internal threads on solids?  External as well? Trying the sweep around a helix and it seems very finnicky. Any help appreciated. Thank you 

Import a Cap Screw matching your thread size from McMaster-Carr, Place it, Boolean remove it. Easiest way IMHO. 

[Newbeeee™]

4 minutes ago, CEMENTHEAD said:

Import a Cap Screw matching your thread size from McMaster-Carr, Place it, Boolean remove it. Easiest way IMHO. 

Don't forget to scale the screw to get the pitch diameter correct, and then add the appropriate root radius to the thread

 

[cruzila]

7 hours ago, Newbeeee™ said:

Don't forget to scale the screw to get the pitch diameter correct, and then add the appropriate root radius to the thread

 

"It's just a guideline"

[Newbeeee™]

11 minutes ago, cruzila said:

"It's just a guideline"

"Oh, Yeh, but print is king anyway"....

 

[cncappsjames]

On 10/19/2023 at 10:30 AM, RustyG said:

Does anyone have an easy way to model internal threads on solids?  External as well? Trying the sweep around a helix and it seems very finnicky. Any help appreciated. Thank you 

Unless ABSOLUTELY POSITIVELY NECESSARY, that juice just isn't worth the squeeze. Like @JParissaid, the amount of headroom (read computational horsepower) that feature/those features will consume truly makes it not worthwhile. @crazy^millman says he doesn't use it 95%.... personally, I don't do it like 99% of the time. I only time I ever model threads is when thread timing is critical.

[jpatry]

18 hours ago, cncappsjames said:

Unless ABSOLUTELY POSITIVELY NECESSARY, that juice just isn't worth the squeeze. Like @JParissaid, the amount of headroom (read computational horsepower) that feature/those features will consume truly makes it not worthwhile. @crazy^millman says he doesn't use it 95%.... personally, I don't do it like 99% of the time. I only time I ever model threads is when thread timing is critical.

The last time I was handed modeled threads, they weren't even modeled to the right pitch.

On 10/20/2023 at 3:26 PM, Newbeeee™ said:

"Oh, Yeh, but print is king anyway"....

 

And the print says "see CAD model for dimensions not given"

[crazy^millman]

On 10/21/2023 at 4:03 PM, jpatry said:

The last time I was handed modeled threads, they weren't even modeled to the right pitch.

And the print says "see CAD model for dimensions not given"

Dealing wit that now. Rivets for nut plates called out, but not dimensioned or modeled. Follow the model, but not modeled. Not dimensioned, but have to be added to the CNC program. I have history with the customer and found older parts with the same nut plates that were dimensioned so I used those dimensions as my supporting documentation to use with inspection so they can sale the parts to the Rocket Company the parts are for.

[JoshC]

3 hours ago, crazy^millman said:

Dealing wit that now. Rivets for nut plates called out, but not dimensioned or modeled. Follow the model, but not modeled. Not dimensioned, but have to be added to the CNC program. I have history with the customer and found older parts with the same nut plates that were dimensioned so I used those dimensions as my supporting documentation to use with inspection so they can sale the parts to the Rocket Company the parts are for.

are you guys saying someone left some dimensions off a blueprint, that's unheard of!

[crazy^millman]

4 minutes ago, JoshC said:

are you guys saying someone left some dimensions off a blueprint, that's unheard of!

Companies are putting people into space doing this. You cannot make this stuff up which is the scary part about all of this.

[JoshC]

I know what you mean, back when i learned GD&T they taught what is considered industry standards, now everyone makes up their own standards 

[Jobnt]

3 hours ago, crazy^millman said:

Rivets for nut plates called out, but not dimensioned or modeled. Follow the model, but not modeled. Not dimensioned, but have to be added to the CNC program.

xxxx that! Put those holes in a bag and ship 'em separately.