Here is some openSCAD code that can be used to create handrails and stanchions.
The code is still underdevelopment.
To use you can either create and 3d model for a single stanchion or the code can be used to create a single modle multiple stanchions and handrails.
Currently limited to a single style of stanchion and cylindrical handrails.
The first image shows what is generated by the default openSCAD code.
No STLs are currently provided as these would depend on usage.
Designs
Design file
File notes
openSCAD code to generate the required stanchions and or handrail.
Reviews/Comments (subject to moderation)