How Grinders Are Made

Grinders are a common part of almost every smoker’s setup—so ubiquitous, in fact, that most people never think about how they’re made. Unlike an impromptu smoking piece, they’re not something you can whip together at home without some specialized equipment, but it turns out that the manufacturing processes used to make grinders are still pretty straightforward.

Here are a couple of examples of ways that different kinds of grinders are made.

What Are Dry Herb Grinders Made Of?

Grinders can be made of any number of materials, from plastic to forged alloys. While plastic grinders and generic metal blends are what make up a large portion of the most affordable grinders, many mid- and upper-range grinders are made of stainless steel or aluminum, like the ones from Santa Cruz Shredder.

Higher-end aluminum and titanium grinders are often anodized, meaning they’re sealed and strengthened in an electric process that makes the piece less likely to chip and crack. This is super important when it comes to metals with relatively low melting points like the aforementioned two, which when not anodized can be prone to chipping and giving off unsafe fumes when you light them in your dry herb bowl.

Smokers who are particularly concerned about this can opt to skip straight to a stronger metal grinder like one made of stainless steel.

What Parts Does a Grinder Have?

Though all grinders are different and new styles emerge every year, basic functionality is constant across most manual hand grinders. The top two chambers each have a set of opposite-facing teeth (styles vary) that break up the dry herb put between them, which in grinders with three or more pieces then falls down into a lower chamber. Four- and five-piece grinders also have an additional, screened-off area or two below for pollen collection, like this one from Sweet Tooth. Four pieces are the ideal number of parts for a productive herb grinder.

These days, grinders at all price points can also feature add-ons like clear lids, removable and replaceable pollen screens, filling funnels, and turning cranks—all of which take their own level of ingenuity in manufacturing to put together.

How a Basic Plastic Grinder Is Made

When it comes to the basics of smoking, nothing is simpler and more ubiquitous than a plastic grinder. Most no-nonsense plastic grinders are made by injection molding melted thermoplastic resin pellets, which are soft and shapeable when heated.

An engineer puts a design for the grinder together in a 3D program known as CAD (computer-aided design) software. After considering grinder dimensions, teeth shape and distance, wall thickness, and if there’s space for any other helpful features, the engineer sends off the design so that a mold can be made out of either steel or cost-effective (but quicker to wear) aluminum.

The finished mold is placed inside of an injection molding machine between clamps and a nozzle dispensing melted plastic. The plastic is fed into the mold cavity at a high speed and then cooled with lines running cold water or oil. The fully cooled part is then ejected from the mold and ready for packaging and shipping off.

How a Precision Machined Grinder Is Made

Some metal grinders are made in a similar process that uses melted material poured into a mold, known as casting. But more and more, high-end metal grinder manufacturers are turning to precision machining processes using CNC mills. Unlike casting, CNC milling is computer-run and offers a high level of precision and accuracy when making multiples of the same part.

The end quality of a CNC milled grinder depends on a number of things, namely the CAD design used to program the mill’s cutting bits, the skill level of the machinist overlooking the process, the software used by the mill, and the quality of the tool bits and base materials.

Once a design is ready, the machinist (who is also occasionally the designer) starts manufacture with a piece of billet metal, a lump of metal that has been extruded into a slab or block shape. The outside of the billet is shaped to form the grinder design (in most cases a cylinder) and clamped onto the mill table for processing.

The CNC mill’s drill-like rotational cutting tool moves in circles to carve away unneeded material, following the programmed CAD design to first create a lip around the edge of the chamber. This part will overlap the edge of the corresponding chamber and allow the two to spin around one another when the herbs are being ground. With lubricant constantly being applied to the work surface to keep the machine running smoothly, a smaller bit works away at the metal around the grinder teeth, revealing a series of rough spikes that are then honed down by increasingly finer bits.

Grinders with more than two chambers require threading to keep the pieces together. Much like with a household screw, this process is completed using cutting tools called taps and dies on each respective chamber.

If necessary, the pieces then go through the anodizing process to allow for coloring in addition to increased corrosion resistance. Titanium grinders, for their part, can be colored through the process of anodization itself and don’t need any additional dyes the way that aluminum does. Sweet Tooth grinders in particular feature multiple vibrant colors to choose from as well as unique designs.

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