These fly cutters are fine. They left a reasonably good finish on aluminum, 6061, 015β³ DOC, 1700 rpm. My cutting grind wasn't the best but it still came out ok. --------- UPDATE 05/04/2017 The bits that come with it don't cut it for steel, they really don't hold up to a 1018. I took out the HSS bit and put Harbor Freight's Cheapo Grande Milled Carbide Beer in it. It worked great and cut very well on some 1018s. I had no other use for these carbide bits so I figured why not? I resharpened them really quickly to give them the right angles.