Well, it's been quite a long time since the last post, but finally I got a new project, which has been successful so far. Making lots of errors to get myself familiar again
to that learning curve -thing.
So, this time it's engraving, inspiration came from:
http://bbs.homeshopmachinist.net/threads/46469-Get-a-grip-with-a-3D-pantograph!
I'm not ready (yet) to make a 3D engravings, but who knows, how far this project goes...
First thing was to gather materials to build the thing, didn't have an aluminum, or any other suitable metal stock at hand, so I made mahogany slabs for the arms:

Flanged bushings were made of brass, pins were turned of 8mm stainless steel.
For the pivot, I simplified the design even more; I used a 19mm(0.748") steel ball, from the ancient ball-mouse. Soft steel, easy to drill, and tap.
Enough tech talk for now. Instead some results.
First there was this:

Then some blobby testings on Alu:

When filled with an acrylic paint, looks bit smoother:

Then came this:

Sort of a jigsaw puzzle, a technique, that was easier than cut large pieces at once with a fret saw out of plywood.
And finally, I managed to make smoother mirrored version out of 3mm plastic(details later):
First decent engraving on Alu sheet:

Then brass, from different angles:


Looks a lot more rougher, than it's in real size.