I agree with Brian. I used a 1 1/4 forstner bit to drill counter sink holes
in 6X timbers that I used for my shed foundation. Make sure you drill the
counter-sink holes first. If not it is really difficult to keep a large
forstner bit centered with a hand drill. Use flat washers under the screw
head.
I used the same size washer as the hole drilled. Made a nice looking job and
tightened down tight without any crushing of the wood fibers with the large
washers
CC


"Brian V" wrote in message
. ..

"Bob Morrison" wrote in message
k.net...
In a previous post James wrote...
Summary of Questions:

1. Am I planning the correct pilot hole sizes ?


The pilot hole should be no more than 60% of the lag shank.

For 3/8" (0.375") this works out to 0.225", or 7/32".

2. For drilling through 6 inch timbers, what type of drill bits are
better,
the auger type, or spade ?

Either one works, but you will get a cleaner hole with an auger type bit.

3. Is the use of the spade bit the correct type of bit for the
countersinking ?

Again, you can use either one, but the hole will be cleaner with an auger
type bit. You might even consider using a 1-inch hole saw to cut a
groove and then use your spade bit to clean out the hole.

The countersink hole should be just slightly larger in diameter than the
washer under the head of the lag -- you are using washers aren't you?


Make sure you do the counter-sunk holes first. Once you make the pilot
holes it'll be too big for either a spade or auger tip and make a VERY
sloppy hole, of centered as well. If it were me I'd use a forstner (some
call em forsner's) bit for the counter-sunk followed by an auger for the
pilot.