diff --git a/metric_bolts.scad b/metric_bolts.scad
index 4137932..d908144 100644
--- a/metric_bolts.scad
+++ b/metric_bolts.scad
@@ -1,17 +1,26 @@
+capSizeMSizeMultiplier = 1.66*1.01;
+printingKerfMM = 0.6;
+circleFacets = 60;
+boltColour = "LightSkyBlue";
+boltClearanceColour = "LightSteelBlue";
+
 module metricBoltHex(mSize, structural=false, recessNut=0, chamfer=false){
     // Hex diameter = mSize * 1.8, (or 2.0 if structural
     // We add 1% to make the hex slip in better
-    hexDiameter = mSize * (structural?2.0:1.8) * 1.01;
+    hexDiameter = (mSize * (structural?2.0:1.8) * 1.01) + printingKerfMM;
 
+    color(boltColour)
     translate([0,0,(mSize*0.7)/2])
     cylinder(d=hexDiameter,h=mSize * 0.7, $fn=6, center=true);
     
     if(recessNut > 0){
+        color(boltClearanceColour)
         translate([0,0,(recessNut/2)*-1])
-        cylinder(d=mSize * (structural?2.0:1.8),h=recessNut, $fn=6, center=true);
+        cylinder(d=hexDiameter,h=recessNut, $fn=6, center=true);
     }
     if(chamfer){
         chamferHeight = mSize*1.5*0.595;
+        color(boltClearanceColour)
         translate([0,0,(mSize * 0.7)+(chamferHeight/2)])
         cylinder(d1=hexDiameter,d2=0,h=chamferHeight, center=true, $fn=6);
     }
@@ -20,23 +29,28 @@ module metricBoltHex(mSize, structural=false, recessNut=0, chamfer=false){
 module metricSocketCap(mSize, length, structural=false,recessCap=0, chamfer=false){
     //cap size = M number * 1.5.
     // We add 1% to make the cap head spin nicely in the hole.
-    capSize = mSize * 1.5 * 1.01;
-
-    translate([0,0,(length + ((mSize*1.25)/2))])
-    cylinder(d=capSize,h=mSize*1.25, center=true, $fn=360);
+    capSize = (mSize * capSizeMSizeMultiplier) + printingKerfMM;
+    
+    color(boltColour)
+        translate([0,0,(length + ((mSize*1.25)/2))])
+            cylinder(d=capSize,h=mSize*1.25, center=true, $fn=circleFacets);
+    echo (str("cap size is ", capSize));
     if(recessCap > 0){
+        color(boltClearanceColour)
         translate([0,0,(length + ((recessCap/2)+(mSize*1.25)))])
-        cylinder(d=mSize*1.5,h=recessCap, center=true, $fn=360);
+        cylinder(d=capSize,h=recessCap, center=true, $fn=circleFacets);
     }
     if(chamfer){
+        color(boltClearanceColour)
         translate([0,0,(length-((mSize*1.5*0.595)/2))])
-        cylinder(d2=mSize*1.5,d1=0,h=mSize*1.5*0.595, center=true, $fn=360);
+        cylinder(d2=capSize,d1=0,h=mSize*1.5*0.595, center=true, $fn=circleFacets);
     }
 }
 
 module metricShaft(mSize, length, structural=false){
-    translate([0,0,(length/2)])
-    cylinder(d=mSize, h=length+0.01, center=true, $fn=360);
+    color(boltColour)
+        translate([0,0,(length/2)])
+            cylinder(d=mSize+printingKerfMM, h=length+0.01, center=true, $fn=circleFacets);
 }
 
 module metricSocketScrew(mSize, length, structural=false, recessCap=0, chamfer=false){
@@ -45,23 +59,30 @@ module metricSocketScrew(mSize, length, structural=false, recessCap=0, chamfer=f
 }
 
 module metricCapheadAndBolt(mSize, length=40, structural=false, recessCap=0, recessNut=0, chamfer=false){
-    echo (str("Creating a M",mSize, " size, ", length, "mm long caphead and bolt ", chamfer?"with":"without", " chamfering."));
+    capSize = (mSize * capSizeMSizeMultiplier) + printingKerfMM;
+
+    echo (str("Creating a M",mSize, " size, ", length, "mm long bolt with a ", capSize, "mm wide caphead and bolt ", chamfer?"with":"without", " chamfering."));
     if(recessCap){
         echo (str("It has a ", recessCap, "mm recessed cap"));
     }
     if(recessNut){
         echo (str("It has a ", recessCap, "mm recessed nut"));
     }
-    translate([0, 0, 0])
-    metricSocketScrew(mSize, length, structural=structural, recessCap=recessCap, chamfer=chamfer);
-    metricBoltHex(mSize,structural, recessNut=recessNut, chamfer=chamfer);
+    translate([0,0,((length/2)+((mSize*1.25)/2))*-1])
+    union(){
+        translate([0, 0, 0])
+        metricSocketScrew(mSize, length, structural=structural, recessCap=recessCap, chamfer=chamfer);
+        metricBoltHex(mSize,structural, recessNut=recessNut, chamfer=chamfer);
+    }
 }
 
+/**/
+translate([0,10,0])
+metricCapheadAndBolt(6, 40);
 
-translate([0,0,0])
-metricCapheadAndBolt(8, 40);
-translate([10,0,0])
-cylinder(h=40,d=1);
+translate([20,10,0])
+metricCapheadAndBolt(6, 40, recessNut=1, recessCap=1, chamfer=true);
+/**/
 /*
 translate([0,10,0])
 metricCapheadAndBolt(6, 20, recessNut=10, recessCap=10);