Designed as an integral part of the fastener testing system, washers provide the interface between the specimen and the bolt holders.
All washers are designed to conform to ASTM F606 standards, in thickness, width, and hardness. Each washer is engineered to fit a specific bolt holder, so they will seat snugly and securely in the recessed portion of the bolt holder. Numerous diameters and thread/pitch sizes are available, and washers can be engineered to meet customer specifications, so an exact fit can be accomplished.
Principle Of Operation
There are several varieties of washers, each designed to fill different testing purposes: flat (for proof testing or axial tensile testing), wedge (used in conjunction with a plain washer for wedge tensile testing), and counter-sunk (for testing fasteners with a vee shoulder head).
For a typical test, the operator would fit an unthreaded washer under the head of a screw or bolt and a threaded washer onto the threaded section of the fastener (when testing studs, two threaded washers will be used, one on each threaded portion). After fitting the specimen with both washers, the operator would place the fastener into the bolt holder, apply a pre-load to ensure correct seating and adjust the alignment, and begin the test.
In addition to the wide range of standard washers currently available, the White-Max adjustable washer provides a more versatile option. This patented design positively locks to either a flat type or wedge type (4, 6, 8, or 10 degrees) washer by simply rotating the washer top. Users can then perform a combination of proof and tensile strength tests on fasteners without dismantling the specimen assembly to change washer types. This also reduces the number of washers that testers must have on hand to perform a range of tests. This adjustable washer reduces testing time and minimizes additional accessory cost.
- Types of Loading: proof tests, axial and wedge tensile tests
- Specimen Material: metal alloys
- Specimen Types: bolts, studs