It is a battle in the construction industry decades old. Should I use screws or nails? Hopefully by the end of this article you will have a better idea about which to choose. We will cover both the mechanical differences, cost differences, and practical concerns that would sway a user to go from one to the other.
The first question is what are the mechanical differences between the two choices? There are applications where one is explicitly required, such as to meet building code or an ASTM standard. In many cases, however, it is a judgment call made by the people involved weighing the trade-offs between the two choices. Nails have very high shear strength, but weak pullout resistance. Screws have weak shear strength, but high pullout resistance. This is true for the common screws and nails you will find at a typical big-box retailer.
For many years the decision was that simple. However, this is not an accurate assessment of the state of screw technology. If you are willing to pay for it, engineered screws can replace nails in almost all applications with equal or superior characteristics across the board. Specialty screws from brands like Simpson Strong-Tie and SPAX can have exceptional performance characteristics. The choice between screws and nails today is dependent on a variety of factors, but in general is the aggregate of factors that leads to overall cost effectiveness.
What influences cost effectiveness? There are two factors: the cost of the fasteners and their installation and removal times. Nails are significantly faster for the installation, and are typically cheaper. Nails are faster than all but the fastest at putting in screws, even when nailed by hand. However, the downside of nails is that if something goes wrong they are much slower to remove. If a nail gets bent or is installed crooked, it will take considerable time to remedy the situation. If a screw, by contrast, goes wrong it is a very quick fix. Sometimes a rogue nail causes noticeable damage. In some cases this is unacceptable from an appearance perspective. In general nails are a poor choice when requiring a consistent visual appearance. Fixing these problems can cause a lot of time and so screws should be chosen where such a failure, such as a split or fragmented board, in unacceptable. Nails are in general much cheaper than screws, so you have to weigh the installation, damage likelihood, and damage repair times against the cost of the fasteners.
What about other factors? Quality of life for the workers both on the assembly and the crate opening end. Screws require an impact driver in order to install or remove them in any quantity. Although a hand screwdriver may work for a small number of fasteners, it is going to be very difficult for someone to install or remove any significant quantity. If you have a nailgun, and don’t mind the occasional damage nails can cause, nails are preferred for assembly of crates. However, taking apart a crate put together by nails requires some rough handling. A prybar and hammer is the minimum tooling required, and it typically needs someone who has some construction experience. Screws by contrast are simple and much easier to remove with the right equipment.
Is there a difference in choices depending on the destination audience? In general I would say so. For a crate whose destination is a blue collar or manufacturing site, nails are preferable. They can be easily removed by the people there and they will not care about the cosmetic problems nails can cause. By contrast a destination that is an office or scientific facility should use mechanisms for disassembly that would not require such a heavy hand. Either the use of screws or various tool-less systems should be used.
Although historically nails vs screws was a very simple decision, modern high performance screws have made the decision far more complex. Someone who cares about the cosmetics of the finished product should choose screws. Nails should be chosen for ease of assembly and disassembly by professionals in the blue collar or manufacturing industries. Screws or more complex closure systems should be used for cleaner destinations where the brute force approach is going to not be as welcome.