Do You Need a 2×72? Grinder Sizes Honestly Compared

Fair warning and full disclosure in one breath: we sell 2×72 grinders, so of course we’d love the answer to be yes. But the honest answer is more useful than the convenient one, so here it is: no, you don’t need a 2×72 to make knives — you need one to make knives efficiently. Here’s what each machine size actually does, where the cheap ones genuinely suffice, and where the 2×72 earns its reputation.

The Field, Smallest to Largest

No grinder at all — $100 of hand tools

Real knives get made with files, a jig, and sandpaper — the full method is in our no-grinder guide. Slow, instructive, legitimate. Everything below is about buying back hours.

1×30 — the $50–150 gateway

The hardware-store special, and the honest truth is thousands of first knives get made on these. It sharpens well, profiles adequately, and grinds bevels… eventually. The limits: flexy 1″ belts that round your grind lines, tiny work surface, underpowered motors that bog on hard steel, short belt life (a 30″ belt carries a third the abrasive of a 72″ and runs hotter — belt cost per knife is genuinely higher), and minimal belt selection. Verdict: a fine way to discover whether you love this craft for the price of a nice dinner. Just know you’re renting, not buying.

1×42 — the same idea, slightly better

More belt selection than a 1×30 and a bit more real estate. Same fundamental ceiling.

4×36 — the wrong tool that looks right

Sold as a “belt sander” for woodworking: a wide flat platen, slow single speed, and belts in woodworking grits. The width that helps sand a tabletop actively hurts bevel control, and blade-appropriate belts in 4×36 barely exist. Skip it for knives.

2×42 — the budget middle that makes sense

The genuinely respectable budget tier: the right belt width for blades, decent belt availability, and some models accept upgrades (better platens, VFD conversions). A used or modified 2×42 is the best sub-$500 grinding experience. Ceiling: attachment ecosystems, rigidity, and speed control still trail the standard.

2×72 — the standard, for reasons

Why the entire industry converged here: belt selection (every abrasive in every grit ships in 2×72 first — see the belt guide); belt economics (72″ of abrasive runs cooler and lasts far longer per dollar); power and speed control (real motors with VFDs — slow speed is what makes belt sharpening and handle work possible); the tooling-arm ecosystem (flat platen, slack belt, contact wheels, small wheels — one machine becomes six); and rigidity (crisp plunge lines come from machines that don’t flex). It’s not that a 2×72 does anything a patient maker can’t do elsewhere — it’s that it does all of it, faster, repeatably, on one chassis.

The Honest Decision Tree

• Not sure knifemaking will stick? Hand tools or a 1×30. Risk $150, learn everything that matters (see the full cost picture).
• Hooked, on a tight budget? A good 2×42, used market included — or start saving, because…
• Making knife #4 and already annoyed at your machine? That annoyance is the signal. Every maker who upgrades says the same sentence: “I should have bought the 2×72 first.” The money spent on interim machines rarely comes back.
• Going 2×72? Spec it right the first time — variable speed, tilt if you want it, assembled vs. kit — with the 2×72 buyer’s guide and the honest brand comparison (yes, including brands that aren’t ours).

Sources

• BladeForums — decades of “1×30 vs 2×72” community threads
• KnifeDogs — beginner grinder discussions
• Red Label Abrasives — knifemaking industry survey (equipment usage)