Continuing the discussion from Welcome to our forums! Please introduce yourself :
You should be able to import STL files into SketchUp Make 2017–There’s an extension in the Extension Warehouse that you can use. STL files typically need a bunch of cleanup. If I had to choose for a thing like that, I’d be inclined to start with a 2D file and make my own extrusions. I might even just draw them from scratch so as to maintain control over the file size.
Here’s a quick example.
Imported STL file on the left. 5372 entities (edges and faces) It can be cleaned up rather dramatically reducing it to 2290 entities.
In the center is an extrusion from an import of the 2D DXF file. 3838 entities.
On the right is a version I drew from scratch based on the dimensions of the extrusion profile. 1874 entities. It could be reduced more.