One small correction, crucible steel doesn't really require a large furnace, only the right materials. Specifically refractory clay or fire clay.

This type of clay can be used to build a simple closed furnace and crucible. The crucible is loaded with iron, carbon (charcoal) and glass then sealed and placed in the furnace which is then filled with Charcoal and closed. It is vented lower on the sides which allows for airflow while preventing heat loss. This was the method used in the Middle East between the 9th and 11th centuries and as early as 300 BC in India. This is the whole process from the History Channel's "Secrets of the Viking Sword". As you can see the Furnace is not terribly large and rather simple.

In the case of Primitive Technology, I don't know anything about the area he is in, but from the videos he seems to be in a clay heavy region so finding or creating suitable clay seems possible. He has already shown the ability to form and fire clay objects so bricks shouldn't be difficult. It would take a great deal of work, hours of manning the blower to keep the temperature within the furnace high enough to fully melt the steel. Not to mention he would need to produce a small amount of glass, a great deal of charcoal, and would need to pre-smelt the iron source in a bloomery. But I think it is totally within his means to accomplish this.

The end result steel would be nearly identical to modern tool steel.