# HG changeset patch
# User Paul Boddie <paul@boddie.org.uk>
# Date 1439475025 -7200
# Node ID 010f3e69531a0f765b217e32dc39bd4b1f2ffc2e
# Parent  5005760fd9fd734227fb2d0e751e74ac625593c9
Increased the back payload depth, making the back wall thinner.
Increased the PCB lug depths to overlap more substantially.
Increased the groove depth around the inside of the cartridge.

diff -r 5005760fd9fd -r 010f3e69531a cartridge.scad
--- a/cartridge.scad	Tue Aug 04 01:35:03 2015 +0200
+++ b/cartridge.scad	Thu Aug 13 16:10:25 2015 +0200
@@ -162,7 +162,7 @@
 			ROM_CARTRIDGE_int_payload_width;
 
 	int_connector_width = 86.0;	/* limited to the Plus 1 socket dimensions */
-	int_payload_depth = 12.5;	/* maximum depth in the payload section */
+	int_payload_depth = 13.5;	/* maximum depth in the payload section */
 	int_connector_depth = 11.0;	/* maximum depth in the connector section */
 	int_payload_height = 50.8;	/* space between the top and the floor */
 	int_connector_height = 13.5; 	/* vertical offset of bottom/floor of payload area */
@@ -170,7 +170,7 @@
 	/* Side thicknesses. */
 
 	front = 2;
-	payload_back = 2;		/* in the payload area the thickness is reduced */
+	payload_back = 1;		/* in the payload area the thickness is reduced */
 	connector_back = 3.5;		/* the back cavity requires a thicker back wall */
 	top = 3;
 	side = 2; 			/* increased from 1.5 for 3D printing reliability */
@@ -178,7 +178,7 @@
 
 	/* How much extra depth the back provides for mating with the front. */
 
-	groove_width_extra = 1.0;
+	groove_width_extra = 2.0;	/* the depth of the groove accommodating the front rim */
 	front_back_overlap = 1.0;
 	groove_width_overlap = front_back_overlap + groove_width_extra;
 
@@ -283,10 +283,9 @@
 	back_cavity_depth = 1.5;
 
 	/*
-	The effect of the cavity on the inside of the case. The most important
-	measurement is the maximum offset since it defines the width of the
-	internal space that should accommodate the plastic guides of the Plus 1
-	socket.
+	The effect of the cavity on the inside of the case. In principle, the
+	interior of the case could be straight since the plastic guides of the
+	Plus 1 socket are outside the case.
 	*/
 
 	inner_back_slope_depth = 2.5;
@@ -359,19 +358,34 @@
 	pcb_support_offset_from_centre = edge_connector_cutout_back_width / 2
 		- pcb_support_margin;
 
+	/*
+	The PCB lugs protrude through the holes in the PCB. By extending both
+	the front and back lugs by the depth of the back support bump, they
+	overlap by that amount. The "mating" depth is defined as that amount
+	plus an additional amount for adhesion.
+	*/
+
+	pcb_lug_mating_depth = pcb_back_support_bump_depth + 1.0;
+
 	pcb_lug_depth = pcb_back_support_depth +
-		pcb_back_support_bump_depth;
+		pcb_lug_mating_depth;
 	pcb_lug_inner_radius = 1.0;
 	pcb_lug_outer_radius = 5.5 / 2;
 	pcb_lug_offset_from_bottom = 14.35;
 	pcb_lug_offset_from_inside = 5.55;
 
+	/*
+	The cross detail on the back lug is intended to resist the front lug,
+	and thus starts at the point that the front lug ends.
+	*/
+
 	pcb_lug_cross_width = 6.7;
-	pcb_lug_cross_depth = pcb_back_support_depth;
+	pcb_lug_cross_depth = pcb_back_support_depth + pcb_back_support_bump_depth -
+		pcb_lug_mating_depth;
 	pcb_lug_cross_height = 1.4;
 
-	pcb_front_lug_depth = pcb_back_support_bump_depth +
-		pcb_front_support_depth;
+	pcb_front_lug_depth = pcb_front_support_depth +
+		pcb_lug_mating_depth;
 	pcb_front_lug_inner_radius = pcb_lug_outer_radius;
 	pcb_front_lug_outer_radius = pow(
 		pow(pcb_lug_cross_width / 2, 2) +