Tapering A 3D Spiral/Helix/Screw Thread?

Hi all,
I’m pretty new to the whole modelling curved geometries thing & am currently making a screw thread. I’ve modelled the actual thread now, but am wanting to taper off the ends of the thread as you’d see on a self-threading screw. I’ve tried using ‘solid tools’ to ‘subtract’ a curved object from the thread, but that makes all the geometry go weird & faces disappear for some reason. Any other clue as to how this might be done?
Image of my model in case that helps:
In case it helps, I’ve made my screw thread using the method shown here:

One way to do this is to create a “cutter” to form the end of the screws to whatever run-out you’d like.


You can take the easy way out and use the Draw Whorl plugin/extension … Extension | SketchUp Extension Warehouse


Hi Dave, thanks for the quick reply! Don’t mind too much where the taper occurs, but had intended to taper what I’ve already drawn.

This is the method I tried, using ‘solid tools’ ‘subtract’ function, but the geometry went all whack on me…

OMGGGGGG why hasn’t this extension been brought up in Sketchup posts before?! When I searched how to model screw threads or anything it came up with other extensions & methods which made a basic spiral/whatever, but that extension looks perfect!! Thanks a million!

You bet. Make sure to thank the author!


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