No, you shouldn't have to drill it out. The special tap that comes with the kit (if you bought the kit) is also a reemer. And yes, that's the correct thread pitch. The inserts come in different lengths. Make sure you have the right length. I would recommend using a good 6 point socket to drive the tap with, so that the tap stays straight as possible when you're starting it. I usually use a deep socket and shimm it so that the hex part of the tap is completely supported by the walls of the socket...makes it more stable. I was an aircraft mechanic in the Navy for 9 years...one of my specialties was fixing damaged threads and broken fasteners that morons created. I just loved those left-handed mechanics that the Navy "made"...they were usually the guys that screwed fasteners that were TOO long into blind holes....and torqued em down till the broke off...thinkin they could make em fit. Sorry...I'm rambling now. LOL.