poster-tube-lid: convert to oring: introduce vars, and calculate seal_thick

diff --git a/poster-tube-lid.scad b/poster-tube-lid.scad
index 93577660b677b8ffe7bceb31cd5b94aeb4664cab..4ea02d9fdf16f3d04c91f056906803ac33041fcd 100644 (file)
--- a/poster-tube-lid.scad
+++ b/poster-tube-lid.scad
@@ -18,9 +18,14 @@ bayo_behind = 3.5;
 bayo_interf_width = 2.0;
 bayo_interf_slope = 0.75;
 
-seal_thick = 0.1;
 seal_recess = [ 2.0, 2.0 ]; // recess depth, recess height
 
+oring_thick = 5.0;
+oring_bore = 62.0;
+
+oring_upper_embed_angle = 45;
+oring_compress = 0.1; // proportion
+
 side_taper = 1.0;
 
 bayo_above_gap = 1.0;
@@ -44,6 +49,12 @@ bayo_entry_z = bayo_entry;
 bayo_inramp_x = bayo_entry;
 bayo_inramp_z = bayo_entry;
 
+oring_mid_dia = oring_bore + oring_thick;
+oring_outer_dia = oring_mid_dia + oring_thick;
+
+seal_thick = (1 - oring_compress) * oring_thick/2
+  * (1 + cos(oring_upper_embed_angle));
+
 side_height = rivet_posn + bayo_behind + rivet_thick/2;
 side_thick = rivet_tall + over_rivet_wall;