Diamond Cup Grinding Wheel

[pattenp]

Which one of these cup grinding wheels is the best style to use to grind down concrete. I'm needing to grind down a high spot (about 4 sqft) on a garage floor about 1/2" to 5/8" down.

 

[mooman]

the first one. I would be helpful if you had someone there with a Shop Vac sucking up the dust as you go. And don't forget to wear a mask.

 

[Packard V8]

Suggest using water when grinding concrete. It's a helluva mess either way, but the water slurry is more easily contained than the airborne grit. It also prevents the worst damage to eyes and lungs

thnx jack vines