So far I've used 3 bits. The 1/8" cartridge worked as expected, although I haven't used it since my first small test piece. The 1/4" round head cleans up after 26 uses to make rough cuts flush with the template. Eventually the pilot drill dulled immediately after the first cut, leaving burn marks with each additional cut. Instead, buy nicer and more expensive beats. Although it may be more expensive at first, you'll never have to buy them again. Otherwise, expect to use each of these tips for a Use project and end up buying a more expensive replacement tip anyway.On the same day the head of the 3/16 straight bit was completely unscrewed.