Trim and join surfaces when one is a set of screw threads

I have downloaded these threads from a parts detail page at McMaster. They are the receiving threads to screw an air nozzle in. The nozzle is oriented correctly, but I cannot get this edge to close so I can make an SLS print. I’ve tried trim, merge, join. The threads can move forward and backward ON AXIS, a little bit (enough to make it work) but how do I get a planar edge on the threads, and get the red surface to meet that non circular edge?


Thread trim.3dm (1.5 MB)

Hi Kenzan - if you UntrimHoles that planar face you can see that the tops of the threads are not cleanly meeting the plane - that has to be fixed first.

Also, you will want to build this at a much tighter tolerance - some of the surfaces in the threads are narrower than the current .01. Use .001 or even .0001 here.


Pascal, Thanks for the quick response. I’ve tried to cap the red object and use that to trim. I’ve trimmed part of it, but part of the threads will not trim for me. I’ve reuploaded the file with a Cplane along the axis of the threads so you can move the threads along the “nozzle” Cplane.
Now you can move the threads along Z to test.

Thread trim.3dm (1.4 MB)

[Uploading: Suck_blower (12 MB) - Rhino 7 Commercial - [Perspective] 5_27_2022 10_46_41 AM.png…]

Hi Kenzan - can you post the original thread part?


Look into Bolt Gen at food for Rhino. I do not know if it will generate tapered threads. If so it is perfect for what you are after.

I realized in asking this, and you asking for information, that this part already has planar edge as manufactured. so I took the original part and oriented. So while I did solve the problem, I still do not know why I could not trim appropriately, and if you could help me understand that, I would be very appreciative.

5340K21_Zinc-Plated Steel Hose Fitting for Hydraulic Fluid.STEP (1.4 MB)

Hi Kenzan - Once the part is in place, you can ExtractSrf and delete all the faces you do not want - just keeping the threads, I guess -

Then Join those to the edge already there in your red part - it seems to match up correctly.


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Thanks so much for your help. As always your support to the community is very appreciated