A recording of a jackhammer with someone growling. You won't know the difference.
I don't think Anata qualifies, too melodic to be brutal but very technical, yes!
Well, for sampling power tool death metal I would go with dueling chainsaws overlaid on a harley engine sound byte with someone burping and puking up bile rounding out the vocal track. The jackhammer can be mixed in for the drum solo track.