Make professional grade box newel posts using band clamps for corner joints that are stronger than the wood itself. The process shown in this video makes joints invisible and eliminates the need for biscuits, splines, lock miters and, most importantly DOES NOT use nails!
Band clamp design is perfectly suited to providing amazing pressure equally to all 4 corners of these post at the same time. The Merle brand band clamps I use have high-tensile steel bands instead of nylon webbing and non-marring ABS plastic pivoting jaw inserts that quickly conform to sides of the post. These features make clamping a complex assembly like hollow square tubes a breeze when compared to other methods and tools.

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