tappet wrench
Noun: A tappet wrench is a type of hand tool, specifically a wrench, characterized by having two parallel, fixed jaws. The separation between these jaws is set and cannot be adjusted. This design allows it to fit precisely onto nuts or bolt heads of a specific corresponding size. It is common for the tool to have this fixed-jaw design on both ends of the handle, with each end sized for a different fastener.
A tappet wrench is used for turning fasteners (nuts, bolts, screws) of a specific, predetermined size. Its non-adjustable, fixed opening provides a secure, snug fit, which helps prevent rounding off the corners of fasteners. It is often used in mechanical work, particularly in confined spaces where a solid grip is essential.
- The mechanic reached for his tappet wrench to tighten the cylinder head bolt in the narrow space.
- A good set of tappet wrenches is indispensable for working on older engines.
- Because the jaws are fixed, you need a separate tappet wrench for each different nut size you encounter.
- The fixed, parallel jaws of a tappet wrench are designed to contact the flats of a fastener fully, distributing force evenly. This makes it superior to an adjustable wrench for critical applications where overtightening or damaging the fastener is a concern.
- In automotive contexts, "tappet" refers to a component in valve trains, and these wrenches were historically essential for adjusting tappet clearances, hence the name.
- Open-end wrench: A more general term for a wrench with a U-shaped opening at one or both ends. A tappet wrench is a type of open-end wrench with a fixed, non-adjustable opening.
- Combination wrench: A wrench that has an open-end (like a tappet wrench) on one end and a box-end (a closed ring) on the other.
- Spanner: The British English term for .
- Fixed wrench
- Open-end spanner (UK English)
- Set of tappet wrenches: Refers to a collection of these wrenches in graduated, standard sizes (e.g., 8mm, 10mm, 12mm).
- a wrench having parallel jaws at fixed separation (often on both ends of the handle)