diff --git a/resources/views/rd/fire-shutter-drawing/index.blade.php b/resources/views/rd/fire-shutter-drawing/index.blade.php
index 787664ec..d490ead0 100644
--- a/resources/views/rd/fire-shutter-drawing/index.blade.php
+++ b/resources/views/rd/fire-shutter-drawing/index.blade.php
@@ -1378,8 +1378,8 @@ function renderSbSide() {
 
             <!-- ━━━━━ 레일 홀 (밑면 전면측 고정부 내) ━━━━━ -->
             ${(() => {
-                const rhX = ox + vt + 30*sc; // 전면에서 약간 안쪽
-                const rhW = Math.min(railHoleW, sbFrontW - vt - 30*sc);
+                const rhX = ox + f50; // 전면판 Seg3 끝 = 레일 개구 시작
+                const rhW = railHoleW; // 70mm (레일 폭)
                 return rhW > 0 ? `
                     <rect x="${rhX}" y="${oy+sH-vt}" width="${rhW}" height="${vt}" fill="rgba(100,116,139,0.2)" stroke="#64748b" stroke-width="1" stroke-dasharray="3 2" rx="1"/>
                     <rect x="${rhX}" y="${oy+sH-railUp}" width="${rhW}" height="${railUp-vt}" fill="rgba(100,116,139,0.08)" stroke="#64748b" stroke-width="0.8" stroke-dasharray="4 2" rx="1"/>
@@ -1414,7 +1414,7 @@ function renderSbSide() {
 
             <!-- ━━━━━ 슬랫 경로 (레일홀 → 상부 → 샤프트 시계방향 감김) ━━━━━ -->
             ${(() => {
-                const railCx = ox + vt + 30*sc + Math.min(railHoleW, sbFrontW-vt-30*sc)/2;
+                const railCx = ox + f50 + railHoleW / 2; // 레일 개구 중앙
                 const rollTopY = shaftCy - rollR;
                 return `
                     <!-- 케이스 외부: 슬랫 하강 -->