Atoma Diamond Plate - #400

Diamond plates are arguably the most important part of the hand sharpening setup—second only to the sharpening stones themselves. Whether you’re flattening a waterstone or regrinding a blade, a high-quality diamond plate is indispensable.

Atoma Diamond Plates are our go-to for both performance and consistency. Available in #140, #400, #600, and #1200 grits, these plates handle everything from aggressive metal removal to fine scratch refinement. The coarser grits (#140, #400, and #600) are excellent for re-establishing bevels on woodworking tools or flattening dished waterstones, while the #1200 plate bridges beautifully to a #1000 waterstone for further refinement.

Two things matter in a diamond plate: cutting performance and flatness. Atoma excels in both. The diamond abrasive is long-wearing and fast-cutting, and the aluminium substrate is consistently the flattest we’ve found—critical for both accurate bevel work and waterstone flattening. A diamond plate that isn't flat will throw your entire sharpening process out of alignment.

For heavy reshaping or repairing chipped blades, the #140 is an aggressive performer—but caution is needed when using it on delicate high-carbon knife edges. For those wanting more control and less bite, the higher grits provide more subtlety while still removing material efficiently.

Atoma plates are also available as diamond sheets, allowing you to reuse a substrate or mount your own. That flexibility, along with their overall durability, makes them a lasting investment in your sharpening workflow. You can find more information on that here.

If you're looking to elevate your sharpening game—with faster grinding, reliable flattening, and long-term precision—Atoma diamond plates are an essential addition to your kit.

Orders over $200 ship FREE (Aus only).
We dispatch every weekday at 2pm.
Regular Postage: $12.50
Express Postage: $19.00
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Select In-Store Pickup at checkout to collect your order at 29 Production Ave, Kogarah 2217.
Store hours 10am-4pm Tues-Fri.

JTA stands behind the quality of our tools with warranty policies that exceed Australian consumer law. Read about them here.