Maybe you could use a mold instead of forming them by extrusion. Square leads were common in the past: http://www.officemuseum.com/pencil_history.htm http://w

Maybe you could use a mold instead of forming them by extrusion. Square leads were common in the past: http://www.officemuseum.com/pencil_history.htm http://www.officemuseum.com/pencil_history.htm This website reminds me of "slate pencils" (soft slate wrapped in paper). I remember my parents having some of these for a message board in our house. You can still get them: http://www.amazon.com/Slate-and-Pencil-by-KCFT/dp/B017N0U4CS/ref=sr_1_6?ie=UTF8&qid=1448597986&sr=8-6&keywords=slate+pencil http://www.amazon.com/Slate-and-Pencil-by-KCFT/dp/B017N0U4CS...