poster-tube-lid: inttroduce top_minthick_by_oring

diff --git a/poster-tube-lid.scad b/poster-tube-lid.scad
index c5b1e8fc45e5cf84b2ff21838b97f31f0e873107..68bb15e439c1417e2f2e48b48eec5a357df483a8 100644 (file)
--- a/poster-tube-lid.scad
+++ b/poster-tube-lid.scad
@@ -1,7 +1,8 @@
 // -*- C -*-
 
 main_dia = 71.2 + 0.50 - 2.26;
-top_thick = 4;
+top_minthick_middle = 4;
+top_minthick_by_oring = 2.5;
 
 main_cnr = 4.0;
 
@@ -61,6 +62,9 @@ seal_thick = oring_y_rad * (1 + cos(oring_upper_embed_angle));
 side_height = rivet_posn + bayo_behind + rivet_thick/2;
 side_thick = rivet_tall + over_rivet_wall;
 
+top_thick = max(top_minthick_middle,
+               top_minthick_by_oring + oring_y_rad);
+
 top_z = top_thick + seal_thick;
 
 bayo_entry = bayo_behind / 3.0;