Face it, filing plastic models is a fact of life when you work with a 3D printer. This is tedious work, which can leave your hand but a withered claw!
This object is an ergonomic handle for small "hobby" or needle files which are commonly used to finish 3D-printed models. The cross section is a Relaux triangle, which is slightly sculpted in order to provide a pencil-style grip which enables fine control and reduces fatigue. .
These handles are designed to fit needle files with a cylindrical shank 3mm in diamter. Examples include http://www.homedepot.com/p/Nicholson-5-1-2-in-Assorted-Hobby-Craft-Mini-File-Set-6-Piece-42030L/203336567 and http://www.amazon.com/Nicholson-Piece-Hobby-Carded-Length/dp/B00002N5JT. Additionally, the handles may be scaled in order to fit other sizes and types of files.
In addition to the file handles, a matching stand is also provided. It holds the files securely and arranges them for easy access. A center cavity in the stand can be used to store another tool which you are always reaching for, such as a pair of tweezers.
I hope someone will find these useful, print them out, and upload a few photos. I'm not a very good hand model, I'm afraid.
Both the file handles and the stands should be printed in the given orientations. The file handle model features a thin disk which promotes better adhesion to the build surface; it should be easy to remove with a knife, machete, or oxygen torch. No supports should be used to print either the file handle or base.
The handles are assembled onto the files by a press fit. I have hand the best results by clamping the cutting surface of the file vertically between two pieces of wood in a bench vise, and hammering the handle down onto the file. If you have a propane torch, assembly can be greatly eased by heating the file shank (but be careful not to anneal the cutting edges!)