diff --git a/readme.md b/readme.md
index 5385fc5..aaa293f 100644
--- a/readme.md
+++ b/readme.md
@@ -5554,9 +5554,10 @@ The module provides `poly_circle()`, `poly_cylinder()` and `poly_ring()` that is
 ### Modules
 | Module | Description |
 |:--- |:--- |
-| ```drill(r, h = 100)``` | Make a cylinder for drilling holes suitable for CNC routing, set h = 0 for circle |
+| ```drill(r, h = 100, center = true)``` | Make a cylinder for drilling holes suitable for CNC routing, set h = 0 for circle |
 | ```poly_circle(r, sides = 0)``` | Make a circle adjusted to print the correct size |
 | ```poly_cylinder(r, h, center = false, sides = 0)``` | Make a cylinder adjusted to print the correct size |
+| ```poly_drill(r, h = 100, center = true)``` | Make a cylinder for drilling holes suitable for CNC routing if cnc_bit_r is non zero, otherwise a poly_cylinder. |
 | ```poly_ring(or, ir, sides = 0)``` | Make a 2D ring adjusted to have the correct internal radius |
 | ```poly_tube(or, ir, h, center = false)``` | Make a tube adjusted to have the correct internal radius |
 | ```slot(r, l, h = 100)``` | Make a horizontal slot suitable for CNC routing, set h = 0 for 2D version |
diff --git a/utils/core/polyholes.scad b/utils/core/polyholes.scad
index a115cb9..dcf5d53 100644
--- a/utils/core/polyholes.scad
+++ b/utils/core/polyholes.scad
@@ -66,9 +66,16 @@ module poly_tube(or, ir, h, center = false) //! Make a tube adjusted to have the
     extrude_if(h, center)
         poly_ring(or, ir);
 
-module drill(r, h = 100) //! Make a cylinder for drilling holes suitable for CNC routing, set h = 0 for circle
-    extrude_if(h)
+module drill(r, h = 100, center = true) //! Make a cylinder for drilling holes suitable for CNC routing, set h = 0 for circle
+    extrude_if(h, center)
         circle(r = corrected_radius(r, r2sides(r)));
+
+module poly_drill(r, h = 100, center = true) //! Make a cylinder for drilling holes suitable for CNC routing if cnc_bit_r is non zero, otherwise a poly_cylinder.
+    if(cnc_bit_r)
+        drill(r, h, center = true);
+    else
+        poly_cylinder(r, h, center);
+
 //
 // Horizontal slot
 //
diff --git a/vitamins/pcb.scad b/vitamins/pcb.scad
index 53020ec..1aac27c 100644
--- a/vitamins/pcb.scad
+++ b/vitamins/pcb.scad
@@ -841,7 +841,7 @@ module trimpot10(vertical, cutout = false) { //! Draw a ten turn trimpot
         rotate([vertical ? -90 : 0, 0, 0]) {
             if(cutout)
                 screw_pos()
-                    cylinder(d = screw_d + 1, h = 100);
+                    poly_drill(r = (screw_d + 1) / 2, h = 100, center = false);
             else
                 color("#2CA1FD") {
                     translate([0, -foot_h / 2, foot_h / 2 + h / 2])
diff --git a/vitamins/smd.scad b/vitamins/smd.scad
index 4a7299c..3a73ae7 100644
--- a/vitamins/smd.scad
+++ b/vitamins/smd.scad
@@ -45,7 +45,7 @@ module smd_led(type, colour, cutout) { //! Draw an SMD LED with specified ```col
     $fn = 32;
 
     if(cutout)
-        cylinder(d = 2.85, h = 100); // For lightguide made from transparent PLA filament
+        poly_drill(r = 2.85 / 2, h = 100, center = false); // For lightguide made from transparent PLA filament
     else {
         color("white")
             linear_extrude(size.z)