Square and coffin-shaped nails are considered the weakest nail shapes due to their straight edges. These straight edges are more prone to snagging and breaking compared to other shapes. This is corroborated by multiple sources.
Several articles and online discussions highlight the vulnerability of square and coffin nails:
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Straight Edges are the Culprit: The straight edges of square and coffin nails are easily snagged on everyday objects, leading to chipping and breakage. Makeup.com and RedditLaqueristas both cite this as a major factor.
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Lack of Natural Strength: The design of square and coffin nails inherently reduces the nail's natural strength compared to shapes with rounded edges. A pointed shape like stiletto nails is also notably weak due to the extreme concentration of stress at the tip. Mylee.co.uk highlights the stiletto as exceptionally prone to breakage.
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Rounded Shapes are Stronger: In contrast, rounded shapes such as round, oval, and squoval nails are generally stronger because the curved edges distribute stress more evenly across the nail, reducing the likelihood of breakage. TheList.com supports this assertion.
In summary, while various factors influence nail strength, the straight edges of square and coffin shapes make them significantly more susceptible to breakage than other nail shapes.
