Simple hand tools made from steel are found in private residences, manufacturing facilities, construction sites and service garages around the world. Many of these tools, such as chisels and pin punches, are purposefully designed to be impacted. Others, including screwdrivers and wrenches, have a different purpose but are quite often impacted when used in ways other then what they were intended.
Tools that are improperly designed or used can bend or crack when being struck with a hammer. The resulting debris or hammer rebound can injure the user or cause damage to surrounding objects. While the effects of the impact failure are rarely severe, a manufacturer can earn a reputation for poor quality that is difficult to overcome. To avoid this problem, tool designers should verify the mechanical design of steel shafts and integrated plastic handle within a controlled test environment, using an appropriate impact system.
To answer this test situation we configured a CEAST 9350 with High Energy option test instrument with a 50,000 lb (222 kN) tup to capture the high-impact loads expected during tool strikes. A standard 2-inch spherical insert (to simulate the head of a hammer) was used to strike the various products, which were all mounted in a custom fixture to ensure direct axial loading. A anti-rebound device prevented second strikes on the specimen.
The DAS (Data Acquisition System) with Visual Impact software provided a wealth of performance data previously not available using a more basic free-fall test technique. Analysis software was used to develop a thorough database of impact energies required to initiate damage in several hand tool designs. Use of the CEAST 9350 also enabled repeat testing at defined energy levels to quantify the service life of tools.