diff --git a/lib/Slic3r.pm b/lib/Slic3r.pm
index 410e0b0b..1b4c5706 100644
--- a/lib/Slic3r.pm
+++ b/lib/Slic3r.pm
@@ -60,6 +60,8 @@ use constant SCALING_FACTOR         => 0.000001;
 use constant RESOLUTION             => 0.01;
 use constant OVERLAP_FACTOR         => 0.5;
 use constant SMALL_PERIMETER_LENGTH => (6.5 / SCALING_FACTOR) * 2 * PI;
+use constant LOOP_CLIPPING_LENGTH_OVER_WIDTH        => 0.15;
+use constant PERIMETER_INFILL_OVERLAP_OVER_WIDTH    => 0.4;
 
 # The following variables hold the objects used throughout the slicing
 # process.  They should belong to the Print object, but we are keeping 
diff --git a/lib/Slic3r/Fill/Concentric.pm b/lib/Slic3r/Fill/Concentric.pm
index 2a7c7823..b66f54bb 100644
--- a/lib/Slic3r/Fill/Concentric.pm
+++ b/lib/Slic3r/Fill/Concentric.pm
@@ -63,7 +63,7 @@ sub fill_surface {
         my $path = $loop->split_at_index($index);
         
         # clip the path to avoid the extruder to get exactly on the first point of the loop
-        $path->clip_end(($self->layer ? $self->layer->flow->scaled_width : $Slic3r::flow->scaled_width) * 0.15);
+        $path->clip_end(($self->layer ? $self->layer->flow->scaled_width : $Slic3r::flow->scaled_width) * &Slic3r::LOOP_CLIPPING_LENGTH_OVER_WIDTH);
         
         push @paths, $path->points if @{$path->points};
     }
diff --git a/lib/Slic3r/Fill/Honeycomb.pm b/lib/Slic3r/Fill/Honeycomb.pm
index 66fbd7eb..b635062c 100644
--- a/lib/Slic3r/Fill/Honeycomb.pm
+++ b/lib/Slic3r/Fill/Honeycomb.pm
@@ -21,7 +21,7 @@ sub fill_surface {
     # infill math
     my $min_spacing = scale $params{flow_spacing};
     my $distance = $min_spacing / $params{density};
-    my $overlap_distance = ($self->layer ? $self->layer->flow->scaled_width : $Slic3r::flow->scaled_width) * 0.4;
+    my $overlap_distance = ($self->layer ? $self->layer->flow->scaled_width : $Slic3r::flow->scaled_width) * &Slic3r::PERIMETER_INFILL_OVERLAP_OVER_WIDTH;
     
     my $cache_id = sprintf "d%s_s%s_a%s",
         $params{density}, $params{flow_spacing}, $rotate_vector->[0][0];
diff --git a/lib/Slic3r/Fill/Rectilinear.pm b/lib/Slic3r/Fill/Rectilinear.pm
index 223b8ca4..eceed4ef 100644
--- a/lib/Slic3r/Fill/Rectilinear.pm
+++ b/lib/Slic3r/Fill/Rectilinear.pm
@@ -31,7 +31,7 @@ sub fill_surface {
         $flow_spacing = unscale $distance_between_lines;
     }
     
-    my $overlap_distance = ($self->layer ? $self->layer->flow->scaled_width : $Slic3r::flow->scaled_width) * 0.4;
+    my $overlap_distance = ($self->layer ? $self->layer->flow->scaled_width : $Slic3r::flow->scaled_width) * &Slic3r::PERIMETER_INFILL_OVERLAP_OVER_WIDTH;
     
     my $x = $bounding_box->[X1];
     my $is_line_pattern = $self->isa('Slic3r::Fill::Line');
diff --git a/lib/Slic3r/GCode.pm b/lib/Slic3r/GCode.pm
index dde29a5f..4bea8ddd 100644
--- a/lib/Slic3r/GCode.pm
+++ b/lib/Slic3r/GCode.pm
@@ -112,7 +112,7 @@ sub extrude_loop {
     # clip the path to avoid the extruder to get exactly on the first point of the loop;
     # if polyline was shorter than the clipping distance we'd get a null polyline, so
     # we discard it in that case
-    $extrusion_path->clip_end($self->layer ? $self->layer->flow->scaled_width : $Slic3r::flow->scaled_width * 0.15);
+    $extrusion_path->clip_end($self->layer ? $self->layer->flow->scaled_width : $Slic3r::flow->scaled_width * &Slic3r::LOOP_CLIPPING_LENGTH_OVER_WIDTH);
     return '' if !@{$extrusion_path->polyline};
     
     # extrude along the path