symbolic thread use in a part family

[Alfonz]

I'm creating a socket head cap screw part family, pretty straightforward and simple. I am using a symbolic thread parameter in my spreadsheet (minor dia). I'm doing that in order to get the minor diameter to display in the drawing. However, I am getting a verify failure because of the shaft diameter parameter from the symbolic thread interface. No matter what I try I get errors, either "major diameter must be greater than the minor diameter" or "must be between major and minor diameters (this depends on how I define the shaft diameter in my expressions).

Anyone have any suggestions?

Thanks,

Al

 

[JohnRBaker]

Attached is a copy of MY Socket Head Cap Screw 'Family Table' template part. Perhaps it will help you with your design, or if you just want to use my file, feel free. BTW, once you place the screw in an assembly, if you wish to see detailed threads instead of the symbolic ones, just edit the expression 'Threads' from a '0' to a '1'. Just remember that it can't be saved in that state, just that it might useful if you wish to create more life-like images or renderings show actual threads.

John R. Baker, P.E.
Product 'Evangelist'
Product Engineering Software
Siemens PLM Software Inc.
Industry Sector
Cypress, CA
Siemens PLM:
UG/NX Museum:

To an Engineer, the glass is twice as big as it needs to be.

 

[DanielFlora]

I know the error you are talking about, I have gotten the same thing before in the past. The method I have been using that has continued to work well is this:
Define all symbolic thread parameters as expressions in your table (THREAD_MAJOR_DIA, THREAD_MINOR_DIA, THREAD_ANGLE, THREAD_PITCH).On a screw/bolt (with external threading), drive the "Shaft Size" parameter with THREAD_MAJOR_DIA ( OR whatever expression that was used to drive the diameter of the shank in your original sketch). On an internal thread, on the inside cylinder of a nut for instance, do just the opposite. Drive major, minor, pitch, angle accordingly and this time, set the "Tapped Drill Size" parameter equal to THREAD_MINOR_DIA.

Daniel Flora

 

[Alfonz]

n, thanks for the part, that was helpful to see how you did yours.

Daniel,
That worked perfectly, once I matched the major dia of the symbolic thread to the major dia of my sketch everything was fine. I missed that when I was creating the part family, thanks!

Now I didn't add pitch diamter into my spreadsheet because I am using a schematic thread and I don't see anyway to switch it to detailed. Am I correct in assuming that unless you are doing a detailed thread the pitch diameter value doesn't impact the model at all?

Thanks,

Al

Design Drafter
Alliant Techsystems

 

[JohnRBaker]

I suspect that that's the case although I've never messed with the values to see if that had any effect of the presentation of the 'thread' when looking at the model or a Drawing view where the threads were visible either in a hidden-line view or in a section view.

John R. Baker, P.E.
Product 'Evangelist'
Product Engineering Software
Siemens PLM Software Inc.
Industry Sector
Cypress, CA
Siemens PLM:
UG/NX Museum:

To an Engineer, the glass is twice as big as it needs to be.

 

[DanielFlora]

I think you will fine without thread pitch or pitch diameter as expressions in your table, to my knowledge this isn't going to mess anything up. NX is not going to give you a warning for instance when trying to put the screw into a hole saying "Pitch diameters are not compatible" or anything like that, so I don't see it being an issue.

-Daniel