Used a 3/32" pilot bit and it broke on the 3rd hole. Luckily I had two spare 3/32" titanium coated drill bits to finish the job but one of them broke on the 7th hole. The challenge was to drill 1" to 1/2" cherry and 1/2" soft maple. Two drill bits should never break just to drill 8 holes! The problem I see is that the Drill does not fit snugly in countersink and slightly off-center This causes the drill to oscillate as it rotates so it does not drill a clean hole and when the countersink engages it attempts to correct itself to center which causes the pilot drill will bend in the hole and eventually break.I haven't tried any other sizes yet to see if they have the same faulty design but it wouldn't surprise me.Do yourself a favor and spend the extra money for one Set of Insty or Snappy countersinks, if you decide to buy them make sure you have some spare pilot bits!