diff --git a/public/js/webgl-book-shape-lab.js b/public/js/webgl-book-shape-lab.js
index d778774..2f4867c 100644
--- a/public/js/webgl-book-shape-lab.js
+++ b/public/js/webgl-book-shape-lab.js
@@ -407,7 +407,7 @@ function coverProfilePointsFromFrame(spineHalf, coverOuterX) {
 }
 
 function calculateSpineWidth(bundleCount) {
-    const minimumWidth = 0.16;
+    const minimumWidth = 0.006;
     if (bundleCount <= 1) return minimumWidth;
     const targetArcLength = (bundleCount - 1) * BOOK_PROFILE.bundleSpacing + OPEN_SEAM_GAP;
     let low = minimumWidth;