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:
- Am I planning the correct pilot hole sizes ?
- For drilling through 6 inch timbers, what type of drill bits are better, the auger type, or spade ?
- 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--