An air drill that turns 6000 rpm is very nice for building or making major repairs to a metal airplane such as an RV. The keyless version here was picked up at Boeing surplus and only fits a limited number of sizes. Air drills come with adjustable keyed chucks or keyless chucks (center). You can often get this drill and charger with an extra battery for $99 on sale at your favorite home store. This is the all-purpose cordless drill by DeWalt (left). In this article, we will take a look at a range of drills and accessories that you may want to add to your toolbox. While many maintenance jobs can be done well enough with this drill, many more, mainly if they include installing new equipment or working in tight places, may require something more specialized. I have two myself, but as handy as that drill is, it is not the best tool for many drilling jobs. Many have the popular DeWalt cordless drill/driver that Home Depot and Lowe’s sell by the carload. Pilot and reaming twist drill sizes for Aluminum Rivets.Everyone has a drill in his or her toolbox. For holes that will require reaming for accuracy, and pilot hole should be produced. 375 inches should be 6 to 10% smaller than the intended match drill size. Typical pilot holes when drilling through 2 to 3 plate thicknesses not exceeding. Remove all burrs with a burr remover before riveting. This is especially true when using a hand drill since the drill speed is slow and there is a tendency to apply more pressure per drill revolution. When holes are drilled through sheet metal, small burrs are formed around the edge of the hole. Never tip the drill sideways when drilling or when withdrawing from the material because this causes elongation of the hole. Use an angle drill or drill extensions and adapters when access is difficult with a straight drill. A drill that wobbles or is slightly bent must not be used because it causes enlarged holes.Īlways hold the drill at right angles to the work, regardless of the position of the hole or the curvature of the material. If the drill wobbles, it may be becauSe of burrs on its shank or because the drill is bent or incorrectly chucked. Before beginning to drill, always test the inserted twist drill for trueness and vibration by spinning the hand drill or running the motor freely and watching the drill end. Extend the index and middle fingers of the left hand against the metal to act as a guide in starting a hole, and as a snubber or brake when the drill goes through the material. Hold the power drill firmly with both hands. Hold a hard, smooth, wooden backing block securely in position behind the hole locations when drilling.ĭrilling is usually done with a hand drill or with a light power drill. Make the center punch mark large enough to prevent the drill from slipping out of position, but punch lightly enough not to dent the surrounding material. The center punch mark acts as a guide and lets the drill grip or bite into the metal with greater ease. Thin sheets of aluminum alloy are drilled with greater accuracy by a drill having an included angle of 118° because the large angle of the drill has less tendency to tear or elongate the hole.Ĭenter punch locations for fastener holes before beginning the actual drilling. When drilling hard metals the twist drill should have an included angle of 118 ° and should be operated at low speeds but for soft metals, use a twist drill with an included angle of 90° and it should be operated at higher speeds. General pilot and reaming drill sizes for aluminum rivets are shown in the table below and discussed in the notes. Ream the pilot hole with a twist drill of the correct size to get the required dimension. This is known as predrilling, and the hole is called a pilot hole. To make a fastener hole of the correct size, first drill a hole slightly undersize. Pilot Holes and Field Matching Drilling Aluminum and Steel
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