For the vast majority of my stud / top plate drilling, I use the Irwin Speed-Bor Max bits in a cordless impact driver.


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The bit has the 1/4" hex shank to snap right into the chuck of the driver. Available in sizes to accommodate Romex, MC, 1/2 and 3/4 EMT, it can also be used with an extension. The three-flute design does a fine job of expelling chips from the hole.
The bits make a fast, very clean hole. If you encounter a nail, while the bit will NOT cut it, the bit will typically just skate over the nail, and drill no further, with little actual damage to the bit. Several nail hits are necessary to significantly dull the bit.
Be advised: The bits require more torque than a 14.4v drill can reliably deliver. Nevertheless, I have no problem powering them with a 9.6v impact driver!

Now, for the impact driver ....


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While I am not going to make any claims as to this particular driver being better then others, it has almost completely replaced my drill in daily use. Getting a driver with a larger battery offers very little increase in power - though you can make more holes between charges.

Apart from driving the Irwin bits extremely well, impact drivers have a very short head; this is mainly because they do not use the usual chuck. As a result, the driver and bit will easily fit between 16"OC studs.

Finally ,,,, and I know this is hard to believe ... but an impact driver transmits ZERO twist to your hand. This means no more banged knuckles, sore wrists, or bent bits from striking something with the bit.

For those needing larger holes, Milwaukee has an impact driver designed to accept their "forstener style" bits.