Modelling complex pieces

[Golem Pens]

So for funsies I want to model these pieces. The nib can probably be modelled flat and then curved (I think?) but the feed is obnoxious (though I really only need the shape, none of the features).

I did find STL files of each but converting those into STP or something else has not gone smoothly.

Just wondering if anyone has thoughts about method, best place to start, etc. I am using FreeCAD.

 

[DavidR8]

STL to STP conversion is fraught with issues. I think there are some online conversion programs

 

[Golem Pens]

I did try that and got massive files and not much success simplifying.

Hence thinking about just starting fresh.

 

[Arbutus]

My $0.02...

In Fusion, I would loft the metal nib shape then wrap it on a cylinder. Then remove the cylinder and extrude the wrapped loft to give it thickness. Fillet the edges as needed.
The finned part looks like a stack of disks fitted onto a cylinder. Design one disk, replicate as a pattern. To get the profile correct, use a 2D sketch to draw the profile over the disk stack, then revolve that profile around the longitudinal axis as a CUT operation to remove the outer diameter.

IMHO fiddling with STL files is a futile exercise.

 

[Golem Pens]

To get the profile correct, use a 2D sketch to draw the profile over the disk stack, then revolve that profile around the longitudinal axis as a CUT operation to remove the outer diameter.

I followed everything but that bit clearly! I'm sure it'll make sense as I go though