It appears from the lack of information as to size of the turnscrew you require, the task at hand and your apparent lack of knowledge in hardening and tempering steel, you need a set of turnscrews made of the proper steel that you can cut to the shape you need and heat treat easy enough if required. If you search the web you can find the information you need on heat treating steel and specifically turnscrews.
All "spring" steel is not created equally.
These turnscrews are excellent and widely used for the tasks I suspect you are planning to tackle and will last you for your lifetime:
https://www.amazon.com/Crown-185X-Cabinet-Screwdrivers-6-Pack/dp/B00EC99Z2O
