These screws are decorative screws that are chrome plated? They are hard? They endure the flame of ignition? You drill them with cobalt drills?..........or do they cut with high speed drills?

Currently i am using a vent liner i made from a stainless cap screw. It is wearing well. After well over 100 primers, there is no detectable wear, but the stainless is quite hard on drills.

Today i reread this thread from beginning to end. Much of the information provided by you, Screwbolts was too much for me to understand when i first read it. Wow, what valuable knowledge you shared with the forum; i am glad this thread was brought back.