Hat block

A hat block, also known as a hat form or bashing block, is a wooden block carved into the shape of a hat by a craftsman known as a block shaper. It is used by hat makers or milliners to produce a hat. Today there are only a handful of block shapers left. Recent years have seen a resurgence of hat wearing, and with it a corresponding need for new hatblocks as students of millinery hone their skills.

Vintage hat blocks are desirable and sought after by enthusiasts. The beauty of the wooden hat block is that it can be re-carved into a new shape or modified unlike aluminium or poly blocks.

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Wikipedia