The Truth, Bullshit and Urban Legends

           "If you can't dazzle them with brilliance, then baffle them with bullshit".  This is the perfect saying for the following.  For three years I have watched people leave bad info in many Internet conferences. Here are some examples....

Milling a Circuit Board using a Plotter and a Dental Drill

               I know where this Urban Legend came from!  The idea was suggested by Don Lancaster in a Hardware Hacker article. Here is a PDF of the article as proof!  Plotters made in the last few years can barely push a pen on paper, don't even think about mounting something to the pen assembly. Most newer plotters use a wire drive system that can slip and get out of sync.  Now if you found an older belt drive plotter here are your next problems.  Plotters run from the a serial port. You need to load the correct driver for the plotter.  The older belt driven plotters ran under DOS. This in itself will make things difficult. DOS is still around but finding the correct driver will be a nightmare.

               Plotters draw the Pad than the Trace when drawing the circuit board artwork. The ink of the Pad and Trace flow together.  Cutting a Pad and then the Trace will leave you with a pad that is not connected to the Trace.  The Eagle circuit board program can produce an outline of the Pads and Traces and output the file as an PLT. You need to cut the outline of the Pads and Traces not a Pad then a Trace..

               Ok you have a super strong belt driven plotter. You bought a used dental drill along with some carbide dental drills. You found the driver!  You drew your artwork and then it happens! The Pen-Up! and Pen-Down! signal is too fast. The solenoid drops the dental drill onto the circuit board. If the bit does not break another problem shows up. Before the bit cuts through the copper it's moving. The plotter was designed for drawing with ink.  Some plotters allow the speed to be changed, most don't.  This is as far as anybody has gotten!!! Feel free to tinker!  My point is the bullshit artists talk about a Plotter and Dental Drill like people everywhere are using them to make circuit boards. It's an almost and an Urban Legend!

Making Circuit Boards with your Inkjet Printer

               Over a year ago I was hanging out in a Homemade Circuit Board conference.  I came up with an idea I called Scratch and Etch. You coat a circuit board with something and then have a CNC machine Scratch the outlines of Pads and Traces and then put the circuit board in acid. One guy used layout blue and he did some tests. It worked! Since then several people have used the Scratch and Etch method.

                 Enter the bullshit artist!  Why Scratch and Etch when you can add liquid floor wax to your printer cartridge. The printer prints the floor wax pattern onto the circuit board. You then drop the circuit board into the acid. Faster than Scratch and Etch, Right? Wrong!  Nobody has gotten this to work but it has managed to kill off the Scratch and Etch idea! Not even close! Bullshit!

CNC machine made from Drill Press and X-Y Table

                This idea is not Urban Legend or Bullshit it is fact!  The problem is the people who pass this idea around have no idea of the time, tools and expertise required to make this happen!  They have never tried converting an X-Y table to CNC. The $100 X-Y table won't be such a bargain if you buy it without knowing what's envolved to convert it to CNC. Here is a website  of someone who made a CNC machine from a Drill Press and an X-Y table.

CNC machine that uses Draw Slides

             This is a fact!  Dan Mauch had an article in the December 1994 issue of Nuts and Volts. People will tell you to contact the magazine for a reprint. One guy does this all the time even though he knows it's not available. Even the author says he does not have a copy of the article. To see the machine click here  and look for the name "DickyBird"

A CNC machine built from scrapped printers


                 This is a fact!  But the printers must be old dot matrix types. The type that remain intact after the plastic case is taken off.  All parts are mounted on metal frame that can be cut to size.  Printer must be driven with a notched belt.  Ideally you start with three of the same type printers.  Finding the really old ones with six wire steppers will allow you to use any cheap stepper controller. Four wire steppers require a more expensive controller.  Hacking the existing  circuit board is a waste of time unless you really know your circuits. Best example Here.


                                                                                                                         John Conrad Kleinbauer

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