I have too many to choose a solid EDC. Usually depends on what I want to carry. Usually tactical folders since that is most of what my collection is. For a while it was a Cold Steel Recon 1 tanto, the a CRKT M16-14M, then a M16-01T, then a Benchmade Mini-Grip, and right now a Gerber mini Applegate-Fairbairn. If I'm going out to my favorite haunts I usually take the Emerson Commander BTS or a Microtech SOCOM elite auto.
Cut up a piece off of a lawnmower blade. Medium carbon steel usually (if not a high carbon in some cases) and generally about 1/8 inch thick. HRC in the low 40's initially so there is still room for some heat treatment.
Years ago my now ex-wife gave me a Cold "detective special" pocket knife. It was kind of a joke. When she first started to shoot with me we found a Colt DS snubby in .38 special. You had a 50% chance of missing anything you shot at while holding the barrel against it. Needless the say the knife has been more dependable than the gun. It even rode on the front of the car for about 2 months. It is the first thing I put on in the morning.