The nonmarring brass tip minimizes damage from metal-on-metal contact and is electrically conductive and supple enough to grasp curved and rough surfaces. Alloy steel screws are stronger than Grade 8 steel screws and have a tensile strength of 180,000 psi. In arid conditions, their black-oxide coating offers a moderate level of corrosion protection. All satisfy ASTM A574 and ASME B18.3 for material quality and dimensional requirements.

If you are unsure of the threads per inch, go with screws with coarse threads, which are the industry norm. Close spacing between fine threads keeps them from loosening due to vibration. Coarse threads are incompatible with them.