Pilot hole

A small hole made before inserting a screw, helping to guide it and reduce the risk of splitting the timber.

A small hole drilled into receiving timber to guide a fastener and reduce the risk of splitting.

A pilot hole in the receiving timber is smaller than the screw's outside thread diameter, leaving material for the threads to grip. It reduces driving resistance and the risk of splitting, particularly in hardwood or thin timber. A clearance hole through the first piece lets the screw pass freely, so its head can pull that piece tightly against the receiving timber.

Distinguish a pilot hole, which lets screw threads grip the receiving timber, from a clearance hole, which lets the screw pass freely through the first piece.

Distinguish a pilot hole, which guides a screw, from a clearance hole, which lets its thread pass through freely.

Distinguish a pilot hole, which guides a screw, from a clearance hole, which lets the screw pass through without its thread gripping.

A smaller hole prepared before inserting a screw, helping guide it and reduce the risk of splitting the material.

Preparing a suitable pilot hole reduces the risk of splitting: a hole that is too small can cause cracking, while one that is too large leaves too little material for the thread to grip.

A small-diameter hole that guides a screw and helps prevent timber splitting.

A small-diameter guide hole, used before a subsequent operation such as inserting a screw.

A small-diameter hole that guides a screw and helps prevent the material from splitting.

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Edexcel GCSE Design and Technology · 1DT0

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Eduqas GCSE Design and Technology · C600