http://lcamtuf.coredump.cx/gcnc/

Guerrilla guide to CNC machining, mold making, and resin casting

Benchtop CNC manufacturing tutorial for robot builders, model makers, and other hobbyists
Copyright (C) 2012 by Michal Zalewski (lcamtuf@coredump.cx)

1. Preface

Hello there, stranger! Let me start by explaining what it's all about - and that should help you decide if this page is what you were looking for.

1.1. The purpose of this guide
I'm a computer geek by day, and a hobbyist robot builder by night. I quickly learned that the craft of robotics - just like many other precision hobbies - requires either remarkably deep pockets, or a combination of outstanding manual skills and easy access to a well-equipped machine shop. Urban dwelling hobbyists who are not blessed with any of these graces tend to give up, resort to expensive and simplistic premade kits, or fall back to junkyard quality engineering.

http://www.robotshop.com/advanced-robot-kits.html

http://ribsngibs.com/images/GDR/Robot_06.jpg

http://robotics.reefat.com/wp-content/uploads/2008/09/my-first-robot-v2.jpg

http://www.hotsolder.com/uploaded_images/robot-partial-796818.jpg

It is amusing that the simplest tasks often prove to be the most challenging: many of us can program a microcontroller without breaking a sweat, but making a simple actuated joint, a gearwheel, or a cover in a desired shape, can beyond the realm of imagination. For the past decade, we were being promised a revolution in desktop manufacturing - but unbeknownst to many, a simple, affordable, and home-workshop-friendly solution is already well within the reach. The only problem with computer numerical control is that the workflows and materials suitable for small scale, hobby engineering are almos completely undocumented, and difficult to discover on your own.

http://en.wikipedia.org/wiki/CNC

Several years ago, I took a huge leap of faith, decided to buy a small CNC mill (Roland MDX-15), set up a resin casting workshop, and invested months of intermittent trial, error, and triumph to understand and befriend both technologies - and document them so that others don't have to go through all the pain. It was well worth it, to be sure: I can now routinely crank out remarkably cool and precise designs in no time, and with only minimal cost. For example, this custom-made subminiature planetary gearbox has a diameter of 12 mm, is about 7 mm tall, and achieves a transmission ratio of 125 to 1; the materials are worth around $1.00:

http://lcamtuf.coredump.cx/rstory/

http://www.rolanddg.com/product/3d/3d/mdx-20_15/mdx-20_15.html

http://lcamtuf.coredump.cx/omni/

[cut - this is a long, detailed article]