Wood screw sizes and thread dimensions are shown in the
following charts according to ANSI B18.6.1-1981 standard. Wood screw sizes of
#0, #1, #2, #3, #4, #5, #6, #7, #8, #9, #10, #12, #14, #16, #18, #20 and #24 are
ANSI B18.6.1 wood screw standard covers the sizes
and dimensions for the various types of
slotted and recessed (Phillips, Frearson, Pozidriv) head wood screws.
The wood screw head types are flat head,
pan head .
The designation of wood screws shall be in following format: Nominal size;
product name, including head style and driving provision; material; and finish.
Ex: 6 x 5/8 Slotted Flat Countersunk Head Wood
Some important notes from the ASME B18.6.1-1981:
- The threads of wood screws are coarse pitch threads and may be either cut or
- Wood screws shall have a gimlet point.
- For cut thread screws, the length of the thread shall be approximately 2/3 of
the nominal length of the screw.
- For rolled thread screws, the length of the thread shall be at least 4 x basic
screw diameter or 2/3 of the nominal screw length, whichever is larger. Screws
with too short nominal lengths shall have threads extending as close to the
underside of the head as possible.
- Material: Wood.screws shall be made from steel, stainless steel, brass, aluminum alloy, or other
materials as designated by the purchaser.
- Standard lengths of wood screws are given below.
- Cut thread type screws are usually supplied with single lead threads for all screw lengths.
- Rolled thread type screws may be supplied with either single lead or double
lead threads. Single lead threads are preferred where the nominal length of the
screw is shorter than 4 times the basic screw diameter.