diff --git a/src/libslic3r/Thread.hpp b/src/libslic3r/Thread.hpp
index f9dc07456c..c407159072 100644
--- a/src/libslic3r/Thread.hpp
+++ b/src/libslic3r/Thread.hpp
@@ -46,11 +46,23 @@ void name_tbb_thread_pool_threads_set_locale();
 template<class Fn>
 inline boost::thread create_thread(boost::thread::attributes &attrs, Fn &&fn)
 {
-    // Duplicating the stack allocation size of Thread Building Block worker
-    // threads of the thread pool: allocate 4MB on a 64bit system, allocate 2MB
-    // on a 32bit system by default.
-    
-    attrs.set_stack_size((sizeof(void*) == 4) ? (2048 * 1024) : (4096 * 1024));
+    // Stack size for our worker threads. Originally duplicated TBB's pool
+    // default (4 MB), but the Emboss text-cut path calls into CGAL's
+    // Polygon_mesh_processing::corefine, which falls back from filtered
+    // interval arithmetic to exact rational arithmetic (mpq_class) on
+    // near-degenerate input, and the constrained 2D triangulation walker
+    // (Triangulation_2::march_locate_2D) can recurse deeply enough to
+    // exceed 4 MB on real models -- producing a SIGBUS at the next thread's
+    // stack guard page on macOS / Linux.
+    //
+    // 16 MB chosen as 4x defensive headroom over the observed crash
+    // threshold (n=1 reproducer at exactly 4 MB on macOS arm64). All three
+    // platforms defer-commit reserved stack pages: macOS / Linux mmap the
+    // stack and only fault in pages on touch; Boost.Thread on Win32 passes
+    // STACK_SIZE_PARAM_IS_A_RESERVATION to _beginthreadex, so the value is
+    // a reserve, not the initial commit. Resident memory therefore stays
+    // proportional to actual stack depth on every target.
+    attrs.set_stack_size(16 * 1024 * 1024);
     return boost::thread{attrs, std::forward<Fn>(fn)};
 }