Herb Grinders

Herb Grinders in 40mm, 50mm, 63mm and 100mm

Most smokers underestimate how much their grinder affects the quality of their sessions. A consistent, even grind is the foundation of good airflow through a bowl, a joint, or a vaporizer. When herb is ground unevenly, with chunks mixed in with dust, you get uneven burning, restricted airflow, and wasted material. A quality metal herb grinder with sharp, well-machined teeth produces a uniform grind every time, which translates directly into smoother draws, more even burns, and more from every pack.

The two decisions that actually matter are size and piece count. Everything else is preference. Get those two right and you will not think about your grinder again for years. If you would rather start from a shortlist, our seven ranked picks cover every size and piece count in the range.

What Size Herb Grinder Do You Need?

Size is the single most common thing people get wrong. Buy too small for how you actually smoke and you will regrind three times a session; buy too large for a pocket and it stays on a shelf.

• 40mm herb grinder — Pocket carry, solo sessions, travel. The most compact size we make and the right call if it lives in a bag. From $15.
• 50mm herb grinder — The default. Enough capacity for a full evening, still comfortable in one hand.
• 63mm herb grinder — Group sessions and grinding ahead. The most popular size in the AFM lineup, and the best balance of capacity and leverage.
• 100mm herb grinder — Bulk grinding at just under four inches across. One turn fills a jar. Built for people who prep once and smoke all week.

2-Piece, 3-Piece, 4-Piece or 5-Piece?

A 2-piece grinder is just a top and bottom: herb goes in, ground herb comes out of the same chamber. A 3-piece adds a separate collection chamber underneath, so ground herb falls through and stays uniform instead of getting over-ground. A 4-piece adds a mesh screen and a kief catcher below that, so trichomes separate out as you go. A 5-piece adds a second screen for finer kief separation. If you have never collected kief before, the jump from 2-piece to 4-piece is the one people notice most.

Why Metal Beats Plastic

Plastic teeth round off, and once they do the grinder tears herb instead of cutting it. Plastic also sheds micro-fragments into your herb as it wears. AFM grinders are machined from aircraft-grade aluminum with diamond-cut teeth that hold their edge for years, shredding cleanly without compacting or tearing, which preserves the trichomes and oils that carry potency and flavor. The threading is smooth enough to open one-handed mid-session. We break the full comparison down in why aluminum grinders beat plastic.

Why Smokers Choose AFM Grinders

• Four sizes — 40mm, 50mm, 63mm and 100mm — for pocket carry through bulk grinding
• 2-piece, 3-piece, 4-piece and 5-piece builds for every level of kief collection
• Aircraft-grade aluminum with diamond-cut teeth that stay sharp
• Kief catcher screens on 4-piece and 5-piece models
• Smooth threading for easy one-handed operation, session after session
• Priced from $15, with free US shipping over $75

Browse all 15 herb grinders below, or read our Best Herb Grinders of 2026 for picks by size and use case. For more essential smoking tools, check out our bong parts and accessories, pair your grind with a glass hand pipe or a fresh bong bowl, or find affordable everyday gear in our Under $50 collection.

Herb Grinder FAQs

What size herb grinder should I get?
A 40mm grinder is built for pocket carry and solo sessions. A 50mm is the everyday default, with enough capacity for a full evening in a size you can still hold comfortably. A 63mm suits group sessions and grinding ahead, and gives you more leverage as you turn it. A 100mm grinder, just under four inches across, is for bulk grinding when you want to prep once and not touch it again for a week.

What is the difference between 2-piece, 3-piece, 4-piece and 5-piece grinders?
A 2-piece grinder is just a top and bottom, so ground herb stays in the grinding chamber. A 3-piece adds a separate collection chamber underneath so herb falls through and does not get over-ground. A 4-piece adds a mesh screen and a kief catcher below it, collecting trichome powder as you grind. A 5-piece adds a second screen for finer kief separation.

Are metal grinders better than plastic?
Yes, for two reasons. Metal teeth machined from aluminum hold a sharp edge for years, while plastic teeth dull and snap, and once dull they crush herb instead of shredding it. Plastic grinders also shed micro-fragments into your herb as the teeth wear down. Aluminum resists corrosion and survives being dropped.

What is a kief catcher and do I need one?
A kief catcher is the bottom chamber in a 4-piece or 5-piece grinder that collects the fine, potent trichome powder falling through the screen as you grind. You do not need one, but it builds a reserve of high-potency material you can use to top off a bowl or a joint, so most people find it worth the upgrade.

How do I clean an aluminum grinder?
Tap out loose material, then use a small brush or a toothpick to clear the teeth and screen. For a deeper clean, soak the parts in isopropyl alcohol, scrub, rinse, and let them dry fully before use. Avoid soaking pieces with O-rings for too long. A clean grinder turns more freely and grinds more evenly.