diff --git a/readme.md b/readme.md
index 6a5c2b1..9b0f87a 100644
--- a/readme.md
+++ b/readme.md
@@ -2030,6 +2030,7 @@ A permanent magnet that can be magnatized and de-magnatized electronically.
 | `opengrab_depth()` | Module height |
 | `opengrab_pcb()` | The PCB |
 | `opengrab_pcb_z()` | PCB offset from the front |
+| `opengrab_screw_depth()` | Max screw depth in pillars |
 | `opengrab_target_thickness()` | Target sheet thickness |
 | `opengrab_width()` | Module width |
 
diff --git a/vitamins/opengrab.scad b/vitamins/opengrab.scad
index 7a78e87..ac6dec6 100644
--- a/vitamins/opengrab.scad
+++ b/vitamins/opengrab.scad
@@ -62,6 +62,7 @@ function opengrab_depth() = depth;                               //! Module heig
 function opengrab_target_thickness() = target;                   //! Target sheet thickness
 function opengrab_pcb() = pcb;                                   //! The PCB
 function opengrab_pcb_z() = depth - pillar - pcb_thickness(pcb); //! PCB offset from the front
+function opengrab_screw_depth() = 4;                             //! Max screw depth in pillars
 
 module opengrab() { //! Draw OpenGrab module
     vitamin("opengrab(): OpenGrab V3 electro permanent magnet");