Zen-Wu 240 Grit XL Diamond Plate and Flattening Stone

Zen-Wu’s stones are the flattest available on the market, with a tolerance of less than a .0005”. The aluminum alloy base is precisely milled with chamfered edges. This 240-grit diamond plate is ideal for quickly removing coarse stock, flattening hand planes, and flattening water stones. You can also use the flat underside as a DIY sandpaper lapping plate or a strop. Plate includes an anti-skid pad.

Dimensions:

• Length: 300mm / 11 ¾”

• Width: 85mm / 3 ⅜”

• Thickness: 20mm / ¾”

Jonathan’s Hot Take:

There’s no way to quantify how much better Zen-Wu’s diamond stones are than other manufactures. Most stones are comically out of true—these are so flat, they have a rainbow iridescence that typically only comes from flatness in aluminum. 

The diamonds are suspended in a brass substrate, which holds the diamonds in place better than steel. This also makes the stone self leveling, ensuring it stays dead flat. 

I love how big and flat this diamond plate is. Most other coarse flattening stones are a cheap skinny taco who's substrate looks like a relief map of uneven diamond aggregate. Flatten your water stones in one or two passes. Take an 80-year-old garage sale Stanley bench plane iron, and reshape it into a flat, chip-free surface in a minute or two. 

Flattening hand planes is a breeze because at almost 4" wide, it’s wider than even a #8 jointer plane. I set up my plane with the blade installed but fully retracted, and I go to town—exactly how I would plane a board with forward strokes. Bonus points for setting up a fence or jig to make sure you stay centered.