Atoma #140 Diamond Plate
Atoma plates have long been the standard for stone flattening plates. They have a unique design which leaves uniform channels between diamond clusters, to allow for proper flow of sharpening debris, and so the flattener does not stick to the stone. The Atoma 140# is also standard for heavy duty knife repair.
If you sharpen your own knives on whetstones, you're going to need a diamond plate to keep those stones flat. I haven't tried the $300+ diamond lapping plates made by nanohone or shapton, but I have tried the cheap $30 diamond plates you can purchase on amazon. After the cheap $30 plate lost all of its abrasive after two uses, I bought the Atoma 140 and couldn't be happier. Keeps my whetstones flat and shows very little signs of wearing away after years of mild use.
I haven't needed to use the atoma for major chip repair (knock on wood), but youtube videos show it'll make quick work of steel removal if needed.
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