Is it possible to thread holes from a stl that has been converted into a step?

[sts0]

I am trying to thread the holes with m5 threads. can anyone tell me if this is actually possible? file attached below. 

[jeff_strater]

in short, no.  STL is a triangle mesh format.  So, holes are composed of a series of planar triangles.  Thread needs a true mathematical cylinder to be applied to.  Now, you can get around that with some work, deleting the triangles, and re-adding the hole as an extrude of a circle, or a Hole feature, but that is a more involved process.