counter sink

[josephlor]

how do you know how dep you have to drill to just countersink the head of a screw?How can you tell which size to use?.They don't tell what number to use for the screw?

[LCHIEN]

The usual is to drill the countersink deep enough so that the head is level with or just below the surface.

You need a contersink bit with a diameter equal to or larger than the head of the screw.

I usually drill the hole, then run the countersink in until it looks about right. I confirm it by turning the screw headisde down and set it in the countersink hle and see that the edges fit within the hole, deepeneing it slightly if the head does not fit within the hole.

I usually use a drill press so that the hole is not ovaled by drilling at an angle and I set the depth stop when I've determined the depth of the first hole so that the others will be identical.

Only if you deep sink a screw do you need to worry about the diameter of the countersink it; then choose one just oversize or the diameter of the plug you may be using.

[Pappy]

Loring gave you some good pointers. The only thing I do different is the sequence. If I am going to drill the countersink and pilot hole with different bits, I make the countersink first then use a tapered bit for the pilot hole. Doing it the other way I have had the countersink wind up slightly off-center, especially if I am using a hand held drill.

Another thing to remember is that the screw head will compress the fibers of the wood. If you want the head to sit flush, don't drive them all the way home with a power driver (Drill). Take them in close with the driver and them snug them down by hand with a screwdriver.

[crokett]

If you are planning to fill the holes to cover the screw heads, I've found a counterbore with a larger bit to be more effective. A 3/8" bit is the perfect size for 99% of the screws I use.