Creating 3D CAD designs in FreeCAD - Revolve tool

The FreeCAD part revolve tool, is as it's name suggests a way of creating a shape by revolving an object around an axis. This is often used with sketches to turn a half profile view into a 3D shape, but can also be used with other input shapes.

Design a model of an air rifle pellet (bullet)

To demonstrate this I've taken a different approach to explaining it, by use the analogy of creating a shape using a metal work machine lathe. This is how I was able to visualise it, and I hope you find it useful as well.

The model I created is a model of an air rifle pellet, but please note this is in no way designed to show you how to create a useable pellet, bullet or any other kind of ammunition for a firearm. This is an important point as this is designed for 3D printing and the material used is completely unsuitable for that purpose. It may result in damage to your gun if you did try and use this.

Instead this is designed to make an approximate scale model at a larger size (eg. 5 x size) which can be used as a useful teaching aid for instructing people how to use a rifle on a shooting range. This is explained in the video below.

electronic digital calipers measuring a bullet / pellet to duplicate in FreeCAD

I first measured the actual air rifle pellet using electronic digital calipers so that I had the measurements for designing a copy.

In the video I explain in terms of how you could picture your 3D designs as 2D cross-section images. I think in terms of using a lathe to remove parts from a cylinder.

I then show how you can use the Polyline tool (along with the M modifier) to create straight lines and curves to represent the shape of the model pellet. I created the model in actual size based on measurements using electronic digital calipers, then scaled it up to 500% original size for printing as a model.