Is drawing needed for modeled threads?

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Hello, I have a modeled anti-backlash lead screw shown in the image below:


My question is: when the thread is already modeled in the CAD file, is it still necessary to include a detailed drawing with the thread’s specification (e.g., pitch, diameter, class) for the manufacturing process? I’ll have my parts procured by an external provider.

Solved by Perry Grant
Hi Greg, Got it, thanks for the advice. I’ll include the thread specs in a drawing to ensure proper accuracy.
    • Xometry Engineer

      If the thread is standard, we don’t recommend modeling it in the CAD provided and instead calling it out in a technical drawing. Threads have different sizes and classes, which relate directly to how the thread will be manufactured and inspected. Modeled threads may not fully incorporate the nuances of a manufacturing process; even if we have the right die or tap for the thread, it becomes a mess to chase if already formed.

      In your drawing I see no clearance between male and female thread features. That’s not the reality of good thread design, as clearance is always necessary, and features must have tolerances. Again, this is a good reason to call out the thread requirement on a drawing so there is something to inspect against.

      If this is a 3D print I would recommend modeling coarse threads, especially if they are custom, but also incorporate adequate surface offset to compensate for the selected process.

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        Greg Paulsen

        Hi Greg,

        Got it, thanks for the advice. I’ll include the thread specs in a drawing to ensure proper accuracy.

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Is drawing needed for modeled threads?
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