Everyone knows that preventing unnecessary wear allows equipment to achieve its full service life as well as reduces the risk of downtime. Of the different kinds of unnecessary wear, dry firing is one of the most destructive for pneumatic dowel drills. That’s why successful contractors do what they can to minimize it from occurring.
Here are three points to understand about dry-firing to avoid costly downtime and to get the most value from your equipment.
What is dry-firing, exactly?
Dry-firing occurs when the pneumatic drill is operating but there’s no pressure on the bit. It’s usually caused by improperly setting up equipment prior to drilling or a delay in turning off the drill motor after reaching the required depth. Imagine holding a chisel in one hand and a hammer in the other. Hit the chisel with all the strength you can muster. If the chisel isn’t pressed against a
Dry firing can cause mushrooming of the drill bit collar, as well as wear to the drill bit latch.
surface, all the energy from your epic hammer blow will travel from the hammer through your fingers and up your arm. The first few swings might not hurt, but you’ll feel the effects after a dozen more swings. Now picture hitting the same chisel with an 14-pound sledgehammer more than 2,000 times a minute, and you’ll have a better idea of how much kinetic energy transfers through dry-firing pneumatic equipment, including dowel drills.
How does it affect equipment?
Like the hammer-and-chisel example, dry-firing sends vibrations through the equipment instead of the concrete surface. It won’t damage equipment right away because most pneumatic equipment can withstand a few blows. However, it will take its toll on the pneumatic piston, bushing and trunnion bolt over time. For example, the stress created by dry-firing can break a
At around $80 each, a broken trunnion bolt on a concrete drill motor can add up to costly repairs.
trunnion bolt, which secures the latch that holds the drill bit. This one part costs about $80, which makes it a fairly costly repair that, if the dry-firing habit continues, will add up to hundreds of dollars and hours of downtime.
What can be done to minimize it?
Training is the best defense against dry-firing. Ensure that operators know how to position the drill along the slab so that drill bits make initial contact with the concrete before drilling, and know when to shut it off after the drill bit achieves the required depth.
