Abstract: A blow plate and blow tube assembly. The blow tube conveys core-making sand from the blow plate to a cavity in a core box for forming a sand core utilized in metal casting. The blow plate has a discharge passage with female threads. The blow tube has a body portion and a tip portion for directing the sand from the blow plate into the core box. The body portion of the blow tube has male threads axially therealong and the blow tube is threaded into the passage in the blow plate and extends from the blow plate for engaging the core box. A nut is threaded onto the male threads of the body portion of the blow tube and is disposed between the blow plate and the core box. The blow tube is made of plastic material and includes a shoulder or sleeve portion between the male threads on the body portion and the conically-shaped tip portion. The conically-shaped tip portion has spaced annular ribs thereabout for forming seals with a conical seat in the core box.