I’ve been attending the CNC Workshop since the very first one (circa 2004 or so). The event’s host and organizer, Roland Freistadt, passed the reins over to Village Press after the 2008 event, and we finally had another workshop this year.
As always, Rick Chownyk had presentations on getting started in CNC. Although I’m past the point of ‘getting started’, Rick is such an entertaining person that I just had to sit in on a session.
Rick also does a demonstration of backyard aluminum casting. While I’ve never tried it myself (and don’t currently have a need for it), I’d be quite confident in the procedure after seeing Rick explain and illustrate the process.
The two neatest new things at the workshop were Carmen Gianforte’s miniature firearms and Helmut’s (whose last name I didn’t catch) homebuilt wire EDM machine.
Despite having an interest in firearms, I know almost nothing about the field of miniature firearms. Carmen explained that they are not models, but are sub-scale replicas, and as such are fully functional.
When I say ‘fully functional’, yes, that means they actually shoot (they even have rifling in the barrel bores). Carmen actually manufactures his own ammunition – I forgot to ask what caliber, but they looked to be around .125″, perhaps less. Making the cartridges is fairly standard (if eye-crossingly tiny) lathe work. But they also need primers, and Carmen makes his own – anvils and all. It took him an immense amount of trial-and-error work to draw the tiny copper discs into cups with a set of progressive dies and punches. For the mercury fulminate, he takes shotshell primers and adds a few drops of water to desensitize the compound, and is then able to smear a bit of the resulting paste into his own primer cups. After pressing these primers into the cartridges with anvil in place, and allowing them to dry, the cartridges are live and can be fired. I have no idea how he adds powder and seats the bullet – I had so many questions for him that I could have quizzed him for a week, yet he very graciously answered all my questions and happily explained his techniques.
Helmut’s wire EDM was a fantastic little machine:
A wire EDM machine uses a copper wire as an electrode to cut a 2D shape in a plate of metal, just like if you took a hot wire to cut a shape in a stick of butter (just much more slowly). Generally wire EDM machines are very large, expensive machines – this is the only homebuilt one I’ve even seen in person, and it’s a clever little contraption. Helmut is able to pull the whole machine up out of the tank (which is filled with distilled water) to inspect progress and make adjustments. The pencil on the back side traces out the pattern being cut (stars in this case).