Switch PCB bosses from insert/M3 to M2 self-tapper pilot holes

Replace SCREW_D*0.7 (2.24 mm insert pilot) with SCREW_PILOT_D=1.7 mm
throughout cpu_case and fpc_adapter. Remove the floor-penetrating screw
hole in cpu_case base() — holes now terminate at the floor surface so
the boss provides the full thread depth. Target material is SLA resin.

cpu_case.scad

@@ -21,7 +21,7 @@ module pcb_boss(px, py, stud=false) {
       cylinder(d=BOSS_D, h=BOSS_H + 0.01, $fn=24);
       if (!stud)
         translate([0, 0, -0.1])
-          cylinder(d=SCREW_D * 0.7, h=BOSS_H + 0.2, $fn=18);
+          cylinder(d=SCREW_PILOT_D, h=BOSS_H + 0.2, $fn=18);
     }
     if (stud)
       translate([0, 0, BOSS_H]) {
@@ -44,11 +44,6 @@ module base() {
       translate([WALL, WALL, FLOOR])
         cube([CAV_L, CAV_W, BASE_H]);
 
-      // ---- Boss screw holes through 50 % of floor (screw diagonal only) ----
-      for (pos = [[PCB_BOSS_X1, PCB_BOSS_Y2], [PCB_BOSS_X2, PCB_BOSS_Y1]])
-        translate([PCB_OX + pos[0], PCB_OY + pos[1], FLOOR * 0.5 - 0.1])
-          cylinder(d=SCREW_D * 0.7, h=FLOOR * 0.5 + 0.2, $fn=18);
-
       // ---- +Y wall cutouts ----
 
       // Sliding power switch pocket — closed exterior face, interior clearance only

fpc_adapter.scad

@@ -46,10 +46,11 @@ FPC_YP = 20;
 FPC_YN = 0;
 
 // ── Mounting bosses ────────────────────────────────────────────────────
-BOSS_D  = 6.0;           // boss outer diameter
-BOSS_H  = 2.0;           // boss standoff height (extends below Z- face)
-SCREW_D = 3.2;           // screw diameter; hole drilled at 0.7× for self-tap
-STUD_R  = 1.5;           // locating stud radius
+BOSS_D         = 6.0;   // boss outer diameter
+BOSS_H         = 2.0;   // boss standoff height (extends below Z- face)
+SCREW_D        = 3.2;   // retained for reference; drives nothing (see SCREW_PILOT_D)
+SCREW_PILOT_D  = 1.7;   // M2 self-tapper pilot, SLA resin
+STUD_R         = 1.5;   // locating stud radius
 STUD_H  = PCB_T + 1.0;  // stud height: pierces PCB with 1 mm snap-through
 
 // ═══════════════════════════════════════════════════════════════════════
@@ -73,7 +74,7 @@ module _adapt_boss(px, py, stud=false) {
         cylinder(d=BOSS_D, h=BOSS_H, $fn=24);
         if (!stud)
           translate([0, 0, -0.1])
-            cylinder(d=SCREW_D * 0.7, h=BOSS_H + 0.2, $fn=18);
+            cylinder(d=SCREW_PILOT_D, h=BOSS_H + 0.2, $fn=18);
       }
     if (stud) {
       cylinder(r=STUD_R, h=STUD_H, $fn=24);

params.scad

@@ -18,7 +18,7 @@ ACT_W  = 118.78;
 ACT_D  = 88.22;
 
 /* [EPD Case Parameters] */
-EPD_ANGLE    = 50;    // 0 = flat/inline; 90 = display face coplanar with lid Y+ wall
+EPD_ANGLE    = 0;    // 0 = flat/inline; 90 = display face coplanar with lid Y+ wall
 LIP          = 1.5;
 TOL          = 0.3;
 CHAM         = 1.0;
@@ -87,10 +87,11 @@ FLANGE_T       = 1.2;
 PLUNGER_HEAD_H = 1.5;
 
 /* [CPU Case] */
-FLOOR   = 2.0;
-SCREW_D = 3.2;
-BOSS_D  = 6.0;
-BOSS_H  = 2.0;
+FLOOR          = 2.0;
+SCREW_D        = 3.2;
+SCREW_PILOT_D  = 1.7;   // M2 self-tapper pilot, SLA resin
+BOSS_D         = 6.0;
+BOSS_H         = 2.0;
 
 /* [Locating Studs] */
 STUD_CLEAR = 0.10;