Vermeer's new Hole Hammer pneumatic piercing tool can operate in a full range of soil conditions and applications, plus offers innovative features that provide optimal control and easy start-up. It is available in 2-, 2 1/2- and 3-in. sizes.
The tool's design enables contractors to purchase one tool and change from a standard replaceable head to a moving-head assembly as they move between varying ground conditions.
"With other designs, contractors have been forced to buy two tools – one moving head tool where the head is independent, and one fixed or replaceable head tool – and have to carry two assets," says Vermeer's Jeff Wage. "With this design, you can change the tool by simply unthreading the nose and putting either nose in the tool… It cuts down on your investment and the quantity of tools you need to own and maintain for working in different conditions."
The standard replaceable head is used in conditions where production of 1 fpm is required. In rocky soil conditions or when production appears to be diminishing, you can install the moving head assembly to achieve better production and improved accuracy.
The moving-head design provides full striking force of the piston to the head of the tool at 400 bpm, pulverizing stones into the surrounding soil. The residual energy generated is used to help the tool body travel through the compacted bore path. This results in greater accuracy in tough soil conditions and reduced tool deflection.
The moving head also incorporates a mechanical reset for the head assembly, helping ensure each blow delivered compacts soil in front of the tool to increase production and accuracy. Because Hole Hammer tools feature a mechanical spring reset design, the head fits tightly to the body of the tool, resulting in easy, smooth starting.
A ribbed tool body provides additional tool grip for traction in loose soils, helping achieve forward impact on each blow. "In looser soil conditions, there is a tendency as the piston comes backward to drag that whole tool assembly backward (known as swimming," Wage notes. "The ribbed feature on the outside actually gives you more ground engagement and more grip on the outside of the tool body."
This enables maximum tool power, strong forward thrust and reduced tool swimming for more accurate bores. Inside the body tube are precision-fitted components that reduce seal wear, overall tool maintenance and operating costs.
The Hole Hammer tool also incorporates an air-on quarter-turn reverse function, allowing the operator to reverse the tool quickly — even with the air on. This feature eliminates the need to shut the tool down to reverse direction, helping to reduce time spent on underground restarts, which can be challenging in wet soil conditions.
Although Wage describes the new tool as a premium product, it doesn't come at a premium cost. Vermeer has chosen to offer the Hole Hammer at the same price as its standard piercing tool lineup.