diff --git a/resources/views/rd/fire-shutter-drawing/index.blade.php b/resources/views/rd/fire-shutter-drawing/index.blade.php
index 07bd01f2..32f677d2 100644
--- a/resources/views/rd/fire-shutter-drawing/index.blade.php
+++ b/resources/views/rd/fire-shutter-drawing/index.blade.php
@@ -1065,7 +1065,8 @@ function fs3dBuild() {
         const stubPinVisible = 200; // 밖에서 보이는 길이 (플랜지 밖)
         const stubPinInside = stubPinTotal - stubPinVisible; // 플랜지 안쪽 (100mm)
         const shaftR = b.shaftDia / 2;
-        const flangeR = shaftR; // 플랜지 외경 = 샤프트 외경 (끝에 딱 들어가는 형태)
+        const shaftWallThick = 4; // 샤프트 관 두께 (4mm)
+        const flangeR = shaftR - shaftWallThick - 0.5; // 플랜지 외경 = 샤프트 내경 - 1mm 공차
         const flangeThick = 10; // 플랜지 두께
         const flangeMat = new THREE.MeshStandardMaterial({ color: 0x78716c, metalness: 0.5, roughness: 0.35 });
         const stubPinMat = new THREE.MeshStandardMaterial({ color: 0x9ca3af, metalness: 0.7, roughness: 0.25 });