An adjustable hook spanner union wrench is a versatile tool designed for turning nuts, bolts, or fittings with slotted or notched surfaces, commonly used in industrial, automotive, and construction applications. It features a movable jaw or hook, allowing it to fit various sizes of fasteners, typically ranging from small diameters (e.g., 20-42mm) to larger ones (e.g., 3/4" to 12-3/4" O.D.). The adjustable design makes it ideal for tasks like adjusting collars, locknut rings, bearings, or pipe unions, offering precise torque and a secure grip to prevent slipping.
 
Key Features:
Materials: Often made of high-strength alloys, carbon steel, or stainless steel (e.g., SS304) for durability and corrosion resistance. Some models, like the GEARWRENCH 81856, feature a black oxide finish for added protection.
Adjustability: Jaws or hooks adjust to multiple positions (e.g., 11 positions in OTC Tools’ model) to accommodate a wide range of fastener sizes.
Applications: Used in heavy-duty tasks such as servicing industrial tractors, automotive repairs, or installing metal structures like bridges and beams.
Design: Many include ergonomic handles or bi-material anti-slip grips for comfort during prolonged use. Some models, like those from HansTool, are chrome-plated for longevity.
Sizes: Available in various sizes, with handle lengths typically from 6" to 24" and jaw capacities from 3/4" to 12-3/4". Common hook thicknesses include 11/32", 13/32", and 15/32".
 
Examples:
GEARWRENCH 81856: 2" to 4-3/4" capacity, black oxide finish, alloy steel body.
OTC Tools 7307: 4-3/4" to 12-3/4" O.D., 24" handle, drop-forged jaws.
Williams WS-474 Set: 4-piece set, 3/4" to 6-1/4" span, industrial black finish, made in the USA.
ShallTools SS304: Chrome-plated, extra-wide jaws, available in 6" and 8" sizes.
 
Safety Notes:
Avoid using damaged or bent wrenches to prevent slipping or injury.
Some models carry Prop 65 warnings for chemicals like titanium dioxide, which may pose health risks.
Do not use as a hammer or for improper tasks to avoid damaging the tool or equipment.