choose drill bit to match arduino

diff --git a/curriculum/challenge-bot.scm b/curriculum/challenge-bot.scm
index 2284e0e24a4be0b49c809d3ee24b41fe42b1bbc3..933c0fa080c8e7150f82b11019ddb8be349c0352 100644 (file)
--- a/curriculum/challenge-bot.scm
+++ b/curriculum/challenge-bot.scm
@@ -31,8 +31,12 @@
                   this means the hole needs to be big enough for the
                   screw body to fit through.
                   we want the screw to stay put once it's in place.
                   this means the hole needs to be big enough for the
                   screw body to fit through.
                   we want the screw to stay put once it's in place.

-                  the threads of the screw will grip the edges of the
-                  hole it's going through.])
+                  we also want the drill bit to be smaller than the
+                  diameter of the thread.
+                  the screw was chosen so that the hole on the arduino
+                  was bigger than the body and smaller than the thread.
+                  we will choose the biggest drill bit that fits through
+                  the hole on the arduino.])

      (p [here's a diagram of a screw]
         (figure :legend "screw" (image :file "arduino-to-deck/screw.png"))))
     (subsubsection
      (p [here's a diagram of a screw]
         (figure :legend "screw" (image :file "arduino-to-deck/screw.png"))))
     (subsubsection