Hand-held rotary rock drills used in quarryoperations may be the dry drill, the blower drill, or thewet drill.The dry drill allows very little air to pass throughthe drill steel while drilling; therefore, you should drill30 seconds and blow 60 seconds. When the hammer isnot running, the dry drill allows enough air to passthrough for cuttings to be blown out of the hole. Drillsteels for this drill comes in lengths of 2, 4, and 6 feetwith tips made of carbon inserts, diamond, or star.The blower drill allows a steady supply of air topass through the drill steel to help remove cuttings fromthe hole while the hammer is running. This type alsopermits air to pass through ths drill steel when thehammer is not running.The wet drill provides a constant supply of waterthrough the drill steel while the hammer is running.LubricationMost rock drill failures and complaints result frombad lubrication.Correct lubrication of rock drillsdepends on the following:1. Selection of the proper lubricant2. Application of enough lubricant for all workingpartsThe lubricant must have the correct viscosity for auniform rate of feed under many temperatures. Besidesbeing just viscous (thick) enough, a good rock drill oilmust have the following:1.2.3.4.5.6.High-film strength and the ability to withstandshock loads.Not “blow” readily, or interfere with valveaction.Not fog, or exhaust toxic gases.Not corrode under any operating condition.Lubricate perfectly at maximum drill speed, atboth high and low temperatures.Not form gummy leftovers with either hot orcold air.An in-line oiler must be used with each drill. Drillmanufacturers recommend installing the in-line oilerwithin 10 to 12 feet from the drill. If the oiler is too farfrom the drill, oil droplets tend to gather on the inside ofthe hose. This condition results in sporadic delivery ofoil to the drill and can result in serious damage to thedrill.SafetyBefore operating the drill, ensure the drill steel andbits are in good condition. Drill steel center holes shouldbe clear and the shanks should be flat and square, notchipped or rounded off. Rock bits should be sharp. Dullrock bits are hard on the drill and the operator. To avoidinjury to yourself and fellow workers, operate the drillas follows:. NEVER pound on stuck steel.Nothing isachieved, and you may damage the drill and bit.l NEVER retract the steel at full throttle. This maydamage the front head parts.. NEVER strike the drill with teds. This may dentthe cylinder or cause other damage.l NEVER drag a drill along the ground, becausethe exhaust ports and other openings may scoop up dirtthat will cause trouble and possible failure.. Blow out the air supply hose and flush out thewater hose before connecting it to the drill to rid the lineof dirt.l Ensure the drill is well-lubricated. Adjust thein-line oiler, so the steel shank always shows a film ofoil.l Keep the drill aligned with the drill steel and hole.Hold the drill firmly and apply even pressure with bothhands.. Keep all hands off the trigger or throttle untilready to start drilling operations.l When drilling, keep your balance and NEVERget your face close to the drill.. Wear safety shoes, safety glasses or impactgoggles, gloves, hearing protection, and a hard hat.. NEVER rest an air tool on the toes of your boots.. NEVER point a drill at another person or start anair drill while it is laying on the ground.. Do NOT use your body to control an active drilland never point an air hose at yourself or others.. Always bleed the airline before removing it fromthe drill.14-13
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