Acquire a cow horn. Horns are available from some crafts retailers specializing in historic pieces or from local slaughter houses. Look for a light-colored horn for scrimshaw projects.
Design the butt piece for the horn. The horn can be cut with the same power and hand tools used in wood working. Cut the large end square and make a tracing of end of the horn on a piece of pine. Cut out the plug with a band or scroll saw. File or sand the plug to fit into the opening in the butt end of the horn.
Drill a hole through the small end of the horn. This hole will serve to dispense the black powder. A plug for this hole can be turned on a lathe or hand carved. It is usually attached to the horn by a short strap.
Fasten a shoulder strap to the horn. This is usually attached to a staple or decorative wood piece attached to the wooden butt plug and tied to the front portion of the horn.
Sand and polish the horn completely smooth. By definition, scrimshaw involves placing ink in small grooves and scratches on the horn's surface. Any inadvertent scratches or roughness will also hold ink. Sand the horn with 220 grit sandpaper followed by polishing it with fine steel wool.
Draw in the design with a pencil. This usually requires a little artistic skill. Work on the design until you are happy with the images and the message they convey. Some horns only have the owner's name and other information. Other horns include scrimshawed scenes including wildlife and people. The design can be as complex or as simple as desired.
Make cuts and scratches in the horn with a knife point or sharp stylus. Follow the designs drawn in pencil in the previous step.
Apply ink to the cuts. Liquid printers ink or even artist’s markers can be used. Wipe away excess ink with a rag or fine steel wool.