Hi guys, I’m new here and a complete beginner so thanks in advance for your patience and any help you might be able to impart.

So I’m attempting to model a solid part which will eventually be machined on a lathe and mill. It’s fairly small in size (35mm at its largest diameter, and around 100mm long roughly) so firstly I’m not overly sure if I should be modelling a scaled up version of it, if that will help with the face geometry at all?

It’s a pretty simple shape - it has a cylindrical middle section which then conically tapers down at each end to a smaller diameter - around ⅔ the diameter of the original middle section. That part seems pretty straightforward - draw a 2D skyline of sorts and then use the follow me tool around one of the end faces to create the 3D shape.

The problem I’m having is that I then want to make four equal, flat, longitudinal, indexed faces along the length of the shape, which will bisect and subsequently “remove” some the cylindrical AND tapered aspects. Like if I dropped a square-ended rectangular cuboid over the part and “shaved off” what was hanging outside of the cuboid’s faces.

Kind of like if this was a real part the process would be to turn the part on a lathe to make the cylinder with tapered ends, then transfer it over to a mill and machine the flat faces onto it. So the cylindrical middle section would now become a rectangular cuboid with four rounded corners (that are leftover from the original cylinder), but those flat faces would also extend out into the tapered parts also, making them partially flat too.

I haven’t the foggiest idea of how to go about this process. I suspect it might involve perhaps drawing out the rectangular cuboid separately and then moving it into the part so that it intersects with it somehow but at that point I get lost and confused because none of the geometry lines/“faces” of the cylindrical part ever meet up with any of the faces of the rectangular cuboid. So some sort of subtractive process doesn’t seem to want to work. And there doesn’t seem to be any video tutorials I’ve been able to find so far that deal with this in any way.

Apologies for not having any photos but at this point I’m not very far along myself - I’m sitting looking at a cylinder with tapered extremities and have yet to get any further. Accuracy of sizing is currently not critical as the shape itself may change dimensions eventually, it’s more the concept of adding the flat faces I somehow need to get to grips with.

Any help would be greatly appreciated.

Thanks again.

Sam.