Adding ISOThread and UNC Thread

app/models/iso_thread.py

@@ -0,0 +1,13 @@
+from sqlalchemy import Float
+from sqlalchemy.orm import Mapped, mapped_column
+
+from app.core.database import Base
+
+
+class IsoThread(Base):
+    __tablename__ = "iso_threads"
+
+    id: Mapped[int] = mapped_column(primary_key=True)
+    diameter_mm: Mapped[float] = mapped_column(Float, nullable=False)
+    pitch_mm: Mapped[float] = mapped_column(Float, nullable=False)
+    depth_mm: Mapped[float | None] = mapped_column(Float, nullable=True, default=None)