Parametric Hat Blocks

As part of a series of projects for Pork Pie Hatters, I’ve been reviving some old hat making equipment through a combination of laser cutting, CNC milling, and some older tried and true fabrication techniques. My favorite of these projects has been a series of hat blocks designed in SolidWorks and milled in ash.

The five Phrenology hats: Adler, Kinsey, Maslow, Freud, and Briggs.

The goal has been to recreate a number of classic hat styles for a complete production run of custom hats. The hats themselves are being fabricated at the Pork Pie Hatters Williamsbug shop. The major challenge of this project has been to recreate a complete series of hat blocks from a series of reference forms and drawings, keeping in mind the key elements crucial to each particular hat style. It would be simple to make a series of hat blocks fit for a complete set of head sizes by taking a single design and scaling it up or down. But, the crucial gesture of each design would be lost. The features like pinches in the front, the curve of the ridge along the crest of the hat, the indent at the top of a pork pie, all shift and scale independently to work holistically on different sized heads.

The process I finally came to was scanning my references in 123D Catch (see the models here), making CAD models of Sean’s equipment, taking orthographic reference photos, and bringing everything into SolidWorks to make models that took all these factors into account and could scale features parametically. This has been the first major experiment I’ve ever done with surface modeling, and even though the process was very taxing and frustrating to begin with, the resulting models are even better than I’d initially pictured.

The first machined prototype.

The best part of modeling these shapes using surfaces is that I’ve been able to create gesture lines that can each scale independently or remain fixed as the hat size (measured in the circumference of the band) shifts. I can shape surfaces made from these lines with a lot of precision and cut them with other surfaces to get exactly the gesture I’m looking for in the blocks. It also allows me to make the kind of decisions that come naturally when shaping a piece of wood by hand. Controlling the surfaces that make up the blocks with curves means that I can shift splines and control points to take out extrinsic bumps and details that spoil the clean aesthetic without completely reorganizing how the model is made. Often times it was simple to pull a line here or measurement there and test how that change would effect the complete series of hat sizes in one go.

All of the variations laid out in SolidWorks

Of course, there was a lot of keyboard banging and hair pulling when models decided they could no longer find valid solutions or mysteriously stopped rebuilding. I can’t tell you the number of times I’ve stared, flabbergasted, at a sweep that decided to form the most complicated, invalid, twisted surface possible rather than make the short elegant jump between two nearby points. I’ve accidentally made a lot of cronuts.

A Maslow hat block. Photo by Numidas Prasarn.

The prototypes in this series have been fabricated by Gotham Machine, and came out incredibly well. You can see a video of the first prototype getting machined here. You can see the final models over here on SketchFab.