[sanddrag]

For economy, the Harbor Freight TiN coated big set is hard to beat. I own several, and my personal set at home has served me over a decade, including lathe use. It includes letters, fractions, and numbers up to 1/2 inch. The index case is junk though.

For aluminum, bright finish HSS is preferred. A US-made set from a reputable manufacturer like Hertel will serve you well, but it will cost you. We have sets of screw machine length drills that are really nice. Most times, you are not drilling very deep.

You may want to invest in a set of drill dispenser drawers from Huot. They are available on Amazon Prime or McMaster, and very worth the price.

As a final note, I treat many drills as a consumable. I don't allow dull drills to remain in our shop. For dull drills under 3/8", I throw them away.