This machine can engrave wood and cut paper. I haven't tried other materials yet because there is no fume extraction capability - plastics generally create toxic gases when burnt.
SAFETY WARNING - Please be safe when using lasers. The laser used in this machine can cause permanent eyesight damage, and probably even blindness. When working with powerful lasers (>5mW), always wear a pair of laser safety glasses designed to block your laser's wavelength.
For a quick overview of the guts of the machine, have a look at the video below
(Note: The machine runs slightly faster now, and also has a different laser heatsink to the one in the video)
For pictures of engravings, skip to the end, or visit my website's gallery:
A spreadsheet containing the parts list is below.
Also, for any Aussies unsure about the laser import laws, I've attached the current rules (at Dec 2013) below. Laser diodes and laser modules (such as the one in this machine) are legal, however laser pointers are prohibited.
This is a pdf version of the following webpage: http://www.customs.gov.au/site/page4372.asp
Step 1: Frame Design
The y-axis is on the bottom of the machine, and provides a moving base for the engraved piece. The x-axis is on the top, and moves the laser assembly (the laser isn't shown in the model).