I’ve been preaching the gospel of the tiny forge for years. Nobody wants to use a little one until they try mine.
I make mostly small to medium knives. I can heat treat a 6” blade, which is more knife than most folks will ever need. My primary steel is overhead garage door coil springs. I can get a railroad spike to forging temperature in this little forge, but by the time I spread the blade portion enough to be thin enough, it gets too wide for the opening. I do spikes in the bigger forge.
If you want a spike knife, make sure the letters HC are stamped on the head. It won’t make a great knife, but I can get them hard enough to make a decent knife.
And if you can take a class locally, it is very much worth it for all the learning curve that you can skip over. I took a two hour class, made 3 nails and a hook. It was $160 through the local folk school. Worth every penny. Those 2 hours probably saved me two weeks of figuring it out on my own.
Patrick