I am building an outside shed, using large timbers and lag screws of two
sizes, 3/8 inch and some 1/2 inch. In some places, I want to
counter-sink the lag screws. I want to see if I am on the right track.

For the 3/8 inch lag screws, I plan to use a 1/4 auger drill bit for a
pilot hole. Would that be the right size ? To countersink the head of
the screw, I plan to use a 1 inch spade drill bit.


For the 1/2 inch screws, I plan to use a 3/8 auger drill bit for the pilot
hole. Again, is this the ideal size ? To countersink the screw head, I
would use a 1 1/2 inch spade drill bit.

I will be using washers, so the countersunk holes must accomodate the size
of the washers.



Summary of Questions:

1. Am I planning the correct pilot hole sizes ?

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

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



I know these are rather "green" questions, but I learn from this group.

Thanks !!

--James--