‰  NOW 40 WPM  ‰  
SHAPED STRUCTURE.  THE MODELING PROCESS IS VERY STRAIGHTFORWARD, COMBINING
BASIC GEOMETRIC SHAPES INTO THE DESIRED SHAPE OF YOUR OBJECT, WHILE
SUBTRACTING AREAS THAT YOU EITHER DO NOT NEED, OR THAT ARE NOT PART OF YOUR
DESIGN.  I STARTED WITH TWO RECTANGLES JOINED BY A HALF CIRCLE TO ACT AS MY
HINGE.  IT WAS NOTHING FANCY AND HARDLY RESEMBLED A STRAIGHT KEY, BUT I
NEEDED A TEST PRINT TO DETERMINE IF THE PLASTIC WOULD GIVE ME ENOUGH
SPRING.  AN HOUR LATER, I WAS HOLDING TH

USES A TECHNIQUE CALLED FUSED DEPOSITION MODELING, OR FDM, A VERY SIMPLE
ADDITIVE PRINTING PROCESS THAT HAS BEEN AROUND SINCE THE 1980S.  A STRAND
OF PLASTIC IS FED INTO AN EXTRUDER THAT HEATS UP TO ROUGHLY 212 C.  I USED
ABS PLASTIC, THE SAME PLASTIC THATS USED FOR JUST ABOUT EVERY PIECE OF
CONSUMER ELECTRONICS IN YOUR HOUSEHOLD.  THERE ARE MANY OTHER KINDS OF
PLASTICS TO CHOOSE FROM, RANGING FROM SOME MADE FROM RECYCLED MILK
CONTAINERS TO PLASTIC COMPOSITES COMBINED WITH WOOD OR COPPER THAT CAN BE
SANDED OR EVEN BUFFED TO A SHINE.  THE PLASTIC IS FED THROUGH THE EXTRUDER
BY A SMALL GEAR DRIVEN BY A STEPPER MOTOR ONE OF MANY IN THE PRINTER.  THE
MELTED PLASTIC IS EXTRUDED THROUGH A VERY SMALL HOLE ONTO A GLASS BED THAT
IS HEATED TO 90 C.  THE HEATED BED PREVENTS THE PLASTIC FROM COOLING TOO
QUICKLY AND POSSIBLY SHRINKING, ULTIMATELY WARPING AND RUINING YOUR PRINT.
THE PLASTIC HARDENS ALMOST IMMEDIATELY AND THE FIRST LAYER OF THE PRINT IS
FORMED.  THE EXTRUDER MOVES ON THE X AND Y AXES, AND THE HEATED GLASS BED
MOVES ON THE Z AXIS.  AS EACH LAYER IS EXTRUDED, THE Z AXIS MOVES DOWN,
ANYWHERE BETWEEN 100 400 MICRONS IN THE CASE OF MY PRINTER, WHICH YOU

A 3D PRINTED KEY FOR STRAIGHT KEY NIGHT EVERYTHING OLD IS NEW AGAIN WHEN
USING A CUTTING EDGE TECHNOLOGY TO MAKE A TRIED AND TRUE TOOL.  MATTHEW
WILLIAMS, W2MDW  I HAVE BEEN FOLLOWING THE PROGRESS OF 3D PRINTING
TECHNOLOGY FOR THE BETTER PART OF A DECADE, AND AFTER WATCHING PRINTERS
GEARED TOWARD THE MAKER AND DIY CROWD BECOME MORE AFFORDABLE, I WAS
THRILLED WHEN MY AMAZING WIFE BOUGHT ME ONE FOR MY BIRTHDAY.  I HAD BEEN
THINKING FOR QUITE SOME TIME ABOUT HOW I COULD APPLY 3D PRINTING TO AMATEUR
RADIO.  BETWEEN CUSTOM ANTENNA INSULATORS, PROJECT ENCLOSURES, RADIO
MOUNTS, REPLACEMENT KNOBS, AND A HUGE VARIETY OF OTHER ITEMS I COULD PRINT,
A STRAIGHT KEY SEEMED LIKE THE MOST OBVIOUS CHOICE FOR THE FIRST ITEM TO
TACKLE.  DESIGNING A STRAIGHT KEY TURNED OUT TO BE A MUCH MORE INTERESTING
AND DAUNTING TASK THAN I HAD FIRST ENVISIONED.  IN THE PAST, I HAVE WRITTEN
SOFTWARE, CONSTRUCTED TRIVIAL CIRCUITS FOLLOWING A SCHEMATIC, AND PLAYED
WITH A VARIETY OF PHYSICAL COMPUTING PLATFORMS LIKE THE ARDUINO.  BUT
MODELING WHAT WOULD ULTIMATELY BE A PHYSICAL OBJECT WAS ALL NEW TERRITORY.
LUCKY FOR ME, THE 3D PRINTING WORLD IS FULL OF MATURE TOOLS AND GUIDELINES
FOR ACCOMPLISHING SUCH A TASK.  THE COOLEST NEW TOOL FIRST, LET ME DESCRIBE
WHAT A 3D PRINTER IS AND HOW IT WORKS.  MY PARTICULAR PRINTER XYZPRINTING
DA VINCI 1R0, CAN PRINT AN OBJECT ROUGHLY 8 X 8 X 8 INCHES IN SIZE.  IT
‰  END OF 40 WPM TEXT  ‰  QST DE W1AW  ƒ