acorn: only render threads if thread_height is nonzero

diff --git a/acorn/acorn-threads.scad b/acorn/acorn-threads.scad
index 7173ae5..d5e7fe2 100644 (file)
--- a/acorn/acorn-threads.scad
+++ b/acorn/acorn-threads.scad
@@ -120,7 +120,9 @@ module acorn (thread_pitch = 3.0,
               }
 
 
-              translate ([0, 0, -0.01]) acorn_thread (internal = true, ring = false);
+              if (thread_height != 0) {
+                   translate ([0, 0, -0.01]) acorn_thread (internal = true, ring = false);
+              }
          }
      }