Your aircraft has several different parts that are very difficult to replicate. When you’re repairing or rebuilding an aircraft, you have to make sure you are building something that is lightweight and airworthy. You know that something as little as the screws you choose could greatly impact the way your aircraft flies. For example, if you choose screws that don’t hold very tightly, you could create tiny bits of drag in the sheet metal plates. Those seemingly innocuous bits of drag will make it even more difficult to fly your aircraft, and will cost you serious amounts of time and money. You’ll have to fly slower or spend more money on fuel. Picking quality screws would prevent this situation. The best way to predict which screws will be right for you is to compare two very common materials: steel and aluminum. Each one has advantages and disadvantages.
Steel MS screws are going to be your strongest options. Aircraft-grade steel is incredibly sturdy and lightweight. It is remarkably reliable as a fastening material, but it is still slightly heavier than other materials. If you buy steel screws, you will have the most reliable and durable screws possible, but you’ll also be adding a few pounds to your plane. Those extra pounds could make all the difference in how much fuel you buy regularly.
Aluminum MS screws are a much lighter weight than steel. They are slightly more expensive, but that money can easily be recouped by the resulting lower fuel costs. Aluminum is an incredibly sturdy material, but it’s more ductile than steel. That means it will harden or soften in extreme temperatures. You might have to replace aluminum screws a little more often than steel, but they will be much lighter in weight. You have to decide which is more of a priority for you.
Buying your screws from a reliable manufacturer is even more important than choosing which material to use.