diff --git a/nuts_bolts.h b/nuts_bolts.h
index b93ffcc..ca4ecf5 100644
--- a/nuts_bolts.h
+++ b/nuts_bolts.h
@@ -22,22 +22,14 @@
 #define nuts_bolts_h
 #include <string.h>
 
-#define ONE_MINUTE_OF_MICROSECONDS 60000000.0
-#define TICKS_PER_MICROSECOND (F_CPU/1000000)
-
-#define max(a,b) (((a) > (b)) ? (a) : (b))
-#define min(a,b) (((a) < (b)) ? (a) : (b))
-
 #define FALSE 0
 #define TRUE 1
 
-// Decide the sign of a value
-#define signof(a) (((a)>0) ? 1 : (((a)<0) ? -1 : 0))
-
-#define clear_vector(a) memset(a, 0, sizeof(a))
-
 #define X_AXIS 0
 #define Y_AXIS 1
 #define Z_AXIS 2
 
+#define clear_vector(a) memset(a, 0, sizeof(a))
+#define max(a,b) (((a) > (b)) ? (a) : (b))
+
 #endif
diff --git a/planner.c b/planner.c
index 4a2011c..8102eec 100644
--- a/planner.c
+++ b/planner.c
@@ -75,6 +75,8 @@ int32_t position[3];
 
 static uint8_t acceleration_manager_enabled;   // Acceleration management active?
 
+#define ONE_MINUTE_OF_MICROSECONDS 60000000.0
+
 // Calculates the distance (not time) it takes to accelerate from initial_rate to target_rate using the 
 // given acceleration:
 inline double estimate_acceleration_distance(double initial_rate, double target_rate, double acceleration) {
diff --git a/stepper.c b/stepper.c
index 92091a5..d0828eb 100644
--- a/stepper.c
+++ b/stepper.c
@@ -39,6 +39,7 @@
 #define STEPPING_MASK (STEP_MASK | DIRECTION_MASK) // All stepping-related bits (step/direction)
 #define LIMIT_MASK ((1<<X_LIMIT_BIT)|(1<<Y_LIMIT_BIT)|(1<<Z_LIMIT_BIT)) // All limit bits
 
+#define TICKS_PER_MICROSECOND (F_CPU/1000000)
 #define CYCLES_PER_ACCELERATION_TICK ((TICKS_PER_MICROSECOND*1000000)/ACCELERATION_TICKS_PER_SECOND)
 
 #define MINIMUM_STEPS_PER_MINUTE 1200 // The stepper subsystem will never run slower than this, exept when sleeping