With round heads

cpu_case.scad

@@ -48,7 +48,8 @@ BOSS_H        =  2.0;   // standoff boss height; PCB bottom sits flush on boss t
 
 /* [Locating Studs] */
 STUD_CLEAR  =  0.10;   // radial clearance per side — close (non-interference) fit in SLA resin
-STUD_H      =  PCB_T + 1.0;   // stud height above boss top: through PCB + 1 mm proud
+STUD_H      =  PCB_T + 1.0;   // stud cylinder height above boss top: through PCB + 1 mm proud
+STUD_R      =  (SCREW_D - 2*STUD_CLEAR) / 2;   // stud pin radius (= cylinder + dome radius)
 
 /* [PCB Standoff Positions — relative to PCB origin] */
 PCB_BOSS_X1   =  2.5;
@@ -107,8 +108,11 @@ module pcb_boss(px, py, stud=false) {
                     cylinder(d=SCREW_D * 0.7, h=BOSS_H + 0.2, $fn=18);
         }
         if (stud)
-            translate([0, 0, BOSS_H])
-                cylinder(d=SCREW_D - 2*STUD_CLEAR, h=STUD_H, $fn=24);
+            translate([0, 0, BOSS_H]) {
+                cylinder(r=STUD_R, h=STUD_H, $fn=24);
+                translate([0, 0, STUD_H])
+                    sphere(r=STUD_R, $fn=24);
+            }
     }
 }