Whether it’s new construction or maintenance, many jobs require drilling holes in concrete. Selecting the right tool for the job is critical, but making the right choice can be complicated. Types of tools, bit holding systems and drill bit types, as well as nature of the job that needs to be done and availability of electric power – these are some of the variables that need to be taken into consideration. First some definitions:
Rotary hammer: A tool that drills using rotation and a hammering action that breaks up the concrete as the bit rotates. Rotary hammers are designed for day-in/day-out use.
Demolition hammer: Heavy-duty tool designed to chip or break up concrete.
Combination hammer: A dual-mode hammer designed to either drill or break up concrete.
Before selecting a hammer, determine the diameter of the holes you need to drill. The diameter of the holes will dictate the type of hammer and the bit holding system you select.
Every tool has its own optimal drilling range. By identifying tools with optimal ranges correlating with the dimensions of the holes required, you can decide which size tool is required. By selecting the optimum hammer designed to drill the holes required, more efficient performance is guaranteed. Though operating the hammer within these ranges offers best results, each hammer also includes the flexibility to drill larger holes as well. The bit-holding system consists of the tool’s internal components that hold the bit in place and transfer energy from the electric motor and gearing mechanism to the bit. Most hammers utilize one of three systems: SDS-plus, ® SDS-max® or spline. Spline is a popular bit holding system that has been used for many years, but is gradually being replaced by the superior SDS-max system. Like doctors have specialties, each bit-holding system operates most efficiently and accurately within a defined range. For each system those ranges are: SDS-plus: 3/16” – 3/4” SDS-max: 1/2” – 1-3/4” Spline: 3/8” – 1-3/8”
Though intermittent drilling at capacity is possible, it’s always better to opt for the next larger hammer if any drilling series requires larger holes. Like any other tool or machinery, constantly pushing a hammer to its extremes will eventually lead to failure. Investing in the next larger hammer up front will pay off in the long run.