Screw Assistant not keeping its round references

[lennart_mueller-wirts]

I like using the screw assistant to create multiple screws and their corresponding threaded mount holes.

First thing that bugs me, is that I can only use multiple locations at once in the mode "Concentric", but most of the time this is a proper mode for me. 

The major flaw is the following:

Often we do not use cylindric bores but slots instead for some adjustability in certain directions. In these I place a working axis marks where the screw should go (mostly centered).

- when I then make a single screw conection choosing the axis as round reference, everything works fine

- when I choose multiple axes as round references the screws are not inserted properly (they drop at the origin) and also the primary screw looses its constraints and becomes red in the model tree with a warning sign :warning: next to it

- when I use cylindric bores as round reference instead, everything works just as it should (single and multiple)

[kacper.suchomski]

Hi

Check the behavior in these cases:

1. Create construction points instead of axes
2. Create a sketch (in part) with center points instead of axes
3. Create a sketch (in assembly) with center points instead of axes

[lennart_mueller-wirts]

Thanks for that quick response.

I've tested what you proposed, but I can not select the points as references at all.

- neither sketch points nor 3D-points

- neither for screw assistant mode "concentric" nor "on point"

Maybe this is due to the points being part of a part in a sub-assembly, but at the same point lie the axes, which I could still select as references

[kacper.suchomski]

Are you sure you have selected the correct settings in the dialog box? 

[ldutkaTUZ58]

Where does one find this "Screw Assistant" feature being mentioned? Thanks

[kacper.suchomski]

https://help.autodesk.com/view/INVNTOR/2025/ENU/?guid=GUID-6E1D4624-B605-4AB1-9DBA-E981495B4933

[lennart_mueller-wirts]

Yes, I am pretty sure. Tested several alternative options. I am quite convinced that - with regards to the axes at least - this is a bug on Inventor's side.

[lennart_mueller-wirts]

Just watch the video. It's in the "Konstruktion" Tab (in English this should be Construction or Assembly). The Assistant is for creating Bolted/Screw Connections.

[kacper.suchomski · Accepted solution]

I think a big problem for the algorithm might be the separate subasemblies used as references for screw positioning.

[lennart_mueller-wirts]

Yeah, but regardless of having Sub-Asm activated or not, I can not select those 3D-points, but Work Axes from the exact same file work - with the issue that screws are placed at the origin (though holes are created correctly).

As a workaround for now I put another volume body filling the hole, that leaves a regular cylindrical hole in the center and use this as reference. Even though is is a bit tedious, it works at least... 🙂

[lennart_mueller-wirts]

Yeah probably, that causes the issue.
I also did some tests on a simple test assembly with just two parts. Because here the axis as reference works as it should (but not if the part is inside a sub-asm) and as everything works properly with a cylindrical hole - also in the sub-asm - this must be a problem with inventor, that needs to be fixed please! 🙂