The cost of operating a hydraulic hammer varies widely depending on tool selection, operating practices and maintenance. Before you even pick up the hammer, make sure you have selected the best work tool for the task at hand.
A variety of tools exist, ranging from the standard chisel to the post driver. “The largest tool range is available for most all 1,000-lb. breakers and down,” says Keith Becker, product development specialist, Atlas Copco. Three types are commonly found on larger breakers: blunt, moil and chisel. “The larger breakers can produce much more power and destroy other types of tools or material that they are being used on. Plus, special designs for the larger breakers could get very expensive.”
Tool choice will be driven by whether your application involves impact breaking or penetration breaking. The difference is how energy is distributed to the material.
Impact breaking is used to break oversize material (boulders) in a quarry or for flatwork (sidewalks, driveways and concrete floors) at demolition sites. “A blunt tool needs to be used because the operator is trying to apply the maximum power onto the material,” notes Becker. “This type of material is usually easy to break. By using the blunt tool, it increases the productivity and makes it easier for the operator to place the tool on the material.”
The bigger surface area of the tool is used to transfer force over a large area of work. “Blunt, super blunt and elephant foot type tools are impact breaking tools,” says Blake Albritton, product support engineer, Brunner & Lay. “Burden is uniformly reduced to smaller fragments. Not precise, it is well suited for large-scale demolition or primary sizing of aggregate.”
With penetration breaking, you want to concentrate the energy on a smaller area. The chisel tool is most commonly used for this process. It penetrates and removes a large piece of material. “The tool is trying to split the material very similar to a hammer and a wood chisel,” says Becker. “It is generally used in trenching. Some quarries use a chisel to make rip rap for erosion applications.”
The small surface of the tool transfers force to a small surface area of the material and breaks with a wedging action. “Point, chisel, pyramid point and square point are penetration breaking tools,” says Albritton. “Large objects are re-sized by breaking off material in chunks. More precise than impact breaking, it is suitable for trenching, selective demolition, utility work and day to day breaking.”
The type of tool required is determined by the material and hardness. “There are some materials that you would assume a chisel would do the best job, but find out that a blunt or moil point will be the most productive,” says Becker. “It is really case by case.”
The moil point is the most common universal tool, and can be used for most jobs. “Blunts are used for breaking slabs and other large-scale demolition work,” says Albritton. “Chisels are used for trenching, mining and slab demolition. Asphalt cutters are used to score tarmac.”
The moil point is designed for demolition of heavily reinforced concrete. “This tool can penetrate through the rebar and wire that is found in concrete buildings, bridges and other structures,” says Becker. “This tool will allow the operator to be very precise in his breaking. The moil point could be used for trenching, as well.”
Prevent common failures
Once you select the right tool, you need to use and maintain it properly.
“When a demolition tool has apparently failed to give satisfactory service, one of the reasons is that typical fractures are caused by blank firing and/or twisting of the tool due to a worn or damaged retainer pin,” says Greg Smith, marketing communications manager, Allied Construction Products. “Other causes could be typical fractures that are caused by excessive bending/leveraging of the demolition tool, or a high stress fracture usually caused by using the tool as an anchor to ‘pull’ the carrier.”