Redundancy is critical to many aspects of survival, and fire-starting is one of the best examples of its value. It only takes one instance of being unable to stay warm, cook food, or boil water because you couldn't start a fire to learn this lesson. Maybe your lighter ran out of fuel, your ferro rod wouldn't ignite damp tinder, your matches fizzled in the wind, or you couldn't find any flint or sparking rocks to strike your fire steel — but if you have several of these options, you'll have much better odds of making one work. Integrating multiple fire-starters into your survival kit is a wise move.
The classic fire steel is one tool that's often overlooked as a relic of the past. It has been used for centuries to generate sparks by striking flint, chert, quartz, agate, or other hard rocks. But even though it's old, it's not irrelevant. The flint and steel method is a great backup to other fire-starting techniques, especially since the necessary rocks are readily available in a variety of environments. For the steel, many bushcraft aficionados will use the spine of a high-carbon knife, or a dedicated striker on a necklace or keychain.
We recently saw a video from YouTuber David West that demonstrates how to make a fire steel from a $1 file from a flea market. West cuts the file to his desired size, grinds down the edges and tang, and drills a hole for a cobra stitch paracord lanyard. He then demonstrates its use with chert and some char cloth made from an old T-shirt.
Since the faces of the file are still abrasive, this tool has a secondary function as a sharpener for knives, axes, and other tools. It's also a cool-looking (and inexpensive) item to add to your EDC gear or gift to a friend. Either way, if you've got access to an angle grinder and power drill, this will make for a fun DIY project.