wrote in message
ps.com...
How long should my bits to be? 9 inch or 18 inch

is auger bits the best choice (0.5-0.75 diameter)?

Thx!


A standard double top plate is 3-3.25" thick in modern construction and no
more than 4-4.5" if built with rough sawn lumber.

I like the auger bits but a cheap spade bit will make a few holes before you
burn it up and will cost about 1/3 the price. The auger bits take a bigger
drill motor so if you are using a 3/8 use the spade bits.