This Cowling 1 diagram displays the required parts for the Ew50 2003 5wk1 Holland 1b5wk-300f1 Cowling 1.
The most reasonably priced component used on the Ew50 2003 5wk1 Holland 1b5wk-300f1 Cowling 1 is the Nut, Spring.
In this schematic the "Screw, Tapping" is used most often.