Yes, tools like pliers and wrenches, which seem utterly unremarkable to later generations, still have to be custom-made in this era.
Not only are they expensive, but if a technician wants tools that fit his hand precisely, he'll probably have to work alongside the blacksmith during production, which takes at least ten days' effort.
As for why blacksmiths don't produce them in batches?
Because every technician has different preferences, and most batch-produced tools would simply not sell.
Take the simplest wrench, for example. In most countries, each company uses its own screw specifications—so which size wrench do you make? And some screws have hexagonal heads, while others are triangular—completely incompatible.
So, the only solution is to have the technician customize, draw up designs for the wrench, and hand them to the blacksmith before work can begin.
