Pilot hole
Encyclopedia
A pilot hole is a smaller hole drilled into a material prior to a larger hole being drilled, widening the hole to the desired width. Drilling a pilot hole prevents a larger drill bit from slipping on the material - a potential safety hazard, as well as an increased likelihood of the work being damaged. Normally, a center punch is used before drilling the pilot hole to ensure that the smaller pilot drill bit does not slip.
Pilot holes may also be used when driving a screw
. When a screw is driven into a material, it can act as a wedge, generating outward pressure which can cause many materials (such as wood
or plastic
) to split. By drilling a small pilot hole into the material, into which a screw is then driven, less 'wedging' takes place, thereby reducing the likelihood of the material being split.
Pilot holes are used on a variety of materials including wood
and plastic
s, though their use is especially essential when drilling into polished or smooth metal, as larger drill bits are very likely to slip on such materials.
Pilot holes may also be used when driving a screw
Screw
A screw, or bolt, is a type of fastener characterized by a helical ridge, known as an external thread or just thread, wrapped around a cylinder. Some screw threads are designed to mate with a complementary thread, known as an internal thread, often in the form of a nut or an object that has the...
. When a screw is driven into a material, it can act as a wedge, generating outward pressure which can cause many materials (such as wood
Wood
Wood is a hard, fibrous tissue found in many trees. It has been used for hundreds of thousands of years for both fuel and as a construction material. It is an organic material, a natural composite of cellulose fibers embedded in a matrix of lignin which resists compression...
or plastic
Plastic
A plastic material is any of a wide range of synthetic or semi-synthetic organic solids used in the manufacture of industrial products. Plastics are typically polymers of high molecular mass, and may contain other substances to improve performance and/or reduce production costs...
) to split. By drilling a small pilot hole into the material, into which a screw is then driven, less 'wedging' takes place, thereby reducing the likelihood of the material being split.
Pilot holes are used on a variety of materials including wood
Wood
Wood is a hard, fibrous tissue found in many trees. It has been used for hundreds of thousands of years for both fuel and as a construction material. It is an organic material, a natural composite of cellulose fibers embedded in a matrix of lignin which resists compression...
and plastic
Plastic
A plastic material is any of a wide range of synthetic or semi-synthetic organic solids used in the manufacture of industrial products. Plastics are typically polymers of high molecular mass, and may contain other substances to improve performance and/or reduce production costs...
s, though their use is especially essential when drilling into polished or smooth metal, as larger drill bits are very likely to slip on such materials.