3D Model of Mechanical Part for Printing

I need a simple mechanical part modeled for 3D printing.

Requirements:
- Create a 3D model based on my hand sketches with measurements
- Must adhere to exact dimensions and tolerances I provide
- I need to have a model which I can tweak in Blender

Ideal Skills and Experience:
- Proficiency in 3D modeling software
- Experience with designing for 3D printing
- Attention to detail and accuracy