show how to twist tighten drill bit

[challenge-bot] / curriculum / challenge-bot.scm

diff --git a/curriculum/challenge-bot.scm b/curriculum/challenge-bot.scm
index 2284e0e24a4be0b49c809d3ee24b41fe42b1bbc3..bcfc7b209decdadf102035f23a835d9cd26c06cd 100644 (file)
--- a/curriculum/challenge-bot.scm
+++ b/curriculum/challenge-bot.scm
@@ -31,12 +31,28 @@
                   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
-     :title [inserting drill bit])
+     :title [inserting drill bit]
+     (p (figure :legend "arduino to deck / insert bit"
+                (image :file "arduino-to-deck/1-insert-bit.png"))
+        [insert the drill bit into the teeth of the drill.
+                insert it far enough that the teeth will clamp on the
+                smooth part of the bit when they are tightened.])
+     (p (figure
+         :legend "arduino to deck / twist tighten drill teeth"
+         (image :file "arduino-to-deck/2-twist-tighten-drill-teeth.png"))
+        [while holding the drill bit, twist end of the drill to tighten
+               the teeth.
+               make sure that the teeth end up gripping the flat part of
+               the drill bit.]))
     (subsubsection
      :title [holding drill])
     (subsubsection