DM8761 wrote:
http://www.locostusa.com/forums/viewtopic.php?f=15&t=15005
The above is the friction drilling thread. I was very impressed by the technology and investigated it after reading the thread. I had a great conversation with an engineer from a company down in Texas that makes equipment to perform friction drilling on a number of materials with hand-held and gang mounted drills. These drills are fairly large and not your typical hand-held, consumer-level units with plastic bodies.
It turns out that to get
reliable results the drills need an electronic controller that gets to a certain speed quickly, holds it for a specific period of time to penetrate and then slows down to form the threads. The controller does get feedback from the drill itself. The controller has to know which particular fastener type you're installing and into which material it is drilling. The Texas company uses fasteners from a German firm and their controllers are programmed for those from the factory, otherwise you need to develop your own programming. He told me they experimented with techniques to do it without a controller, but the failure rate is unacceptable. Failure in his context doesn't mean you don't get a hole with threads, it means the result does not reliably meet engineering requirements and specifications, so is not commercially viable as a manufacturing process.
The all-up price for a basic drill and controller was in the $15,000 to $20,000 range, I believe. The fasteners were also expensive, but I don't recall what they cost. It's a fantastic idea, but not for a Locost build IMHO, at least not at this time.
Cheers,