PORTABLE DRILLS : PURPOSE AND TYPES

The portable drill is a hand-supported, power-driven machine tool that rotates twist drills, reamers, counterbores, and similar cutting tools. The portable drill may be electrically powered by means of an internal electric motor (Figure 1) or may be pneumatically powered (Figure 2). Portable drills are rated by the maximum size hole that can be drilled in steel without overtaxing the motor or drill.

TALADROS PORTÁTILES : PROPÓSITO Y TIPOS

El taladro portátil es una máquina herramienta de soporte manual, accionada por motor que hace girar brocas helicoidales, escariadores, avellanadoras, y herramientas de corte similares. El taladro portátil se puede accionar eléctricamente por medio de un motor eléctrico interno (figura 1) o puede ser accionado neumáticamente (figura-2). Los taladros portátiles son clasificados por el tamaño máximo del agujero que puede ser perforado en el acero sin una exigencia excesiva del motor o de la mecha.

Fig. 1- Portable electric hand drills - Taladros manuales portátiles eléctricos

Fig. 2 - Portable pneumatic hand drills - Taladros manuales portátiles neumáticos

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FREE SHIPPING Powersmith Cordless Compact Drill/Driver Kit 12 Volt, Model# MLDD12K2 $69.99 Fueled by Lithium-Ion batteries for extra power, extra run time, and over a year of storage time on a charge. Part of the Maglithion 12V Lithium-Ion Cordless system. One battery powers all Maglithion tools. Chuck Size (in.): 3/8, Speed (RPM): 0 - 500, Keyless Chuck: Yes, Variable Speed: Yes, Case Included: Yes 3/8in. keyless chuck 23 torque/clutch settings 0-500 RPM variable speed Built-in LED work light Magnesium alloy gear housing Rubberized inserts on control surfaces [Read more] Store: Northern Tool and Equipment Brand: Power Smith FREE SHIPPING Makita Electric Drill 3/8in. Chuck Size, 2500 RPM, 4.9 Amp, Model# 6407 $74.99 This drill boasts a 4.9 Amp motor for excellent performance, coupled with double gear reduction for extra power. It features a low 79db decibel rating for quieter operation. Amps: 4.9, Chuck Size (in.): 3/8, Speed (RPM): 2, 500, Side Handle: No, Keyless Chuck: No, Variable Speed: Yes, Case Included: No Reversible Well balanced, weighs only 3.1 pounds In-line handle for better control Lock-on button Ball and needle bearing construction Belt clip Model 6407 U.S.A. Standard Equipment Chuck key [Read more] Store: Northern Tool and Equipment Brand: Makita FREE SHIPPING Powersmith Cordless Compact Drill/Driver 12 Volt, 0-500 RPM, Model# MLDD12C $29.99 Powered by lithium-ion batteries for extra power, extra run time, and over a year of storage time, this compact drill/driver from Powersmith is every bit as powerful as the batteries that it runs on. Part of the Maglithion 12V lithium-ion cordless system. One battery runs all Maglithion tools. Battery/charger kit sold separately. Speed - No Load (RPM): 0 - 500, Chuck Size (in.): 3/8, Keyless Chuck: Yes, Clutch Settings: 23, Battery Included: No, Charger Included: No, Case Included: No, Tool Weight (lbs.): 3 TOOL ONLY Lithium-ion battery and charger (Item# 399416) sold separately Built-in LED work light Magnesium alloy gear housing Rubberized inserts on control surfaces [Read more] Store: Northern Tool and Equipment Brand: Power Smith FREE SHIPPING Ingersoll Rand IQv Series Cordless Drill/Driver 19.2 Volt, 1/2in., Model D650 $109.99 The Ingersoll Rand 19.2 Volt, 1/2in. IQv Series cordless drill/driver uses IQv technology to deliver maximum performance, durability and battery life and up to 650 in.-lbs. of torque. IQv Series cordless tools combine precision engineering with efficient battery technology to provide the best power per volt available. When compared to leading competitive brands, the IQv Series cordless tools have up to 110% better power-to-weight ratios and provide up to 40% better maximum reverse torque. Max. Torque (in.-lbs.): 650, Volts: 19.2, Speed - No Load (RPM): 0 - 360 / 0 - 1, 300, Chuck Size (in.): 1/2, Keyless Chuck: Yes, Reversible: Yes, Variable Speed: Yes, Side Handle: No, Battery Included: No, Charger Included: No, Case Included: No Provides the most power per pound of any cordless drill/driver in its class Ideal for all drilling, boring, fastening and screwing applications Lightweight composite housing with metal-reinforced subframe Uses 19.2V lithium-ion (#3359104) or Ni-Cd battery (#3359103); sold separately [Read more] Store: Northern Tool and Equipment Brand: Ingersoll Rand Left-Handed Chuck for Drill Doctor Model# DAO2105PF $39.99 This left-handed chuck is designed to work with Drill Doctor Models 500X and 750X. Works with bit size range of 3/32in. to 1/2in. Chuck Key Type: Left Handed Bit size range is 3/32in. to 1/2in. U.S.A. [Read more] Store: Northern Tool and Equipment Brand: Drill Doctor FREE SHIPPING Milwaukee Hole Hawg Electric Drill 1/2in., 1200 RPM, 7.5 Amp, Model# 1676-6 $349.99 Power and torque, thats about all that needs to be said about the Hole Hawg line of drills. The compact design of this drill makes it perfect for drilling between studs and joists. This unit will handle up to a 4 5/8in. Selfeed Bit. An extra-long pipe handle helps you control the power. Features two speed ranges and reverse, 1200 and 300 RPM, this will greatly increase the versatility of this drill. Hi-torque and hi-speed make this the perfect choice for the heavy-duty user. Amps: 7.5, Speed (RPM): 300 and 1, 200, Side Handle: Yes, Keyless Chuck: No, Variable Speed: Yes, Case Included: Yes [Read more] Store: Northern Tool and Equipment Brand: Milwaukee FREE SHIPPING Milwaukee Compact Electric Drill 1/2in., 450 RPM, 7 Amp, Model# 1663-20 $279.99 Big power in a compact drill, the Milwaukee drill is easy to use with its extra long handles. This drill is made for two-handed operation, which is nice for large hole drilling or material mixing, and this drill has the power to handle it. Perfect for dialing in correct speeds in various materials. It also features electronics that enable the tool to maintain speed settings even under changing loads. Hi-torque and versatility make this a premium drill. U.S.A. Amps: 7, Chuck Size (in.): 1/2, Speed (RPM): 115 - 450, Cord Length (ft.): 8, Side Handle: Yes, Variable Speed: Yes Triple gear train for reliable performance 5/8in. spindle and 16 thread Extra long switch and pipe handle for maximum leverage Dial speed control allows user to adjust speed with thumb wheel [Read more] Store: Northern Tool and Equipment Brand: Milwaukee Northern Industrial Tools Drill Bits 1/16in. Dia. to 3/8in. Dia., 20-Pc. Set $7.99 SAE drills range from 1/16 in. to 3/8 in. in 1/64 in. increments. Includes (qty.): 20, Diameter (in.): 1/16 - 3/8 by 64ths, Case Included: Yes [Read more] Store: Northern Tool and Equipment Brand: Northern Tool and Equipment Northern Industrial Cobalt Alloy-Coated Steel Drill Bits 29-Pc. Set $59.99 The Northern Industrial cobalt-coated drill bits are engineered to outlast standard HSS bits up to 6X longer. This set includes an extensive range of sizes for a variety of applications. Includes (qty.): 29, Case Included: Yes, Size: 1/16 - 1/2 by 64ths, Finish Type: Cobalt coated Precision-milled 118 point Metal drill index and storage box [Read more] Store: Northern Tool and Equipment Brand: Northern Tool and Equipment Northern Industrial Air Drill 3/8in. Chuck, 1800 RPM, 4 CFM, Reversible, Keyless $39.99 This air drill features an innovative and ergonomic composite housing that helps reduce vibration. A textured rubber grip insulates against cold temperatures and gives you great comfort and control. 2-gear structure runs smoother and lasts longer than most air tools. Chuck Size (in.): 3/8, Keyless Chuck: Yes, Air Consumption (CFM): 4, CFM at Load: 4, Speed (RPM): 1, 800, Air Inlet Size (in. NPT): 1/4, Min. Hose Size (in.): 3/8, Variable Speed: Yes, Reversible: Yes, Side Handle: No [Read more] Store: Northern Tool and Equipment Brand: Northern Industrial Tools Northern Industrial Air Drill 1/2in. Chuck, 700 RPM, 4 CFM, Reversible, Keyless $69.99 This air drill features an innovative and ergonomic composite housing that helps reduce vibration. A textured rubber grip insulates against cold temperatures and gives you great comfort and control. 2-gear structure runs smoother and lasts longer than most air tools. Chuck Size (in.): 1/2, Keyless Chuck: Yes, Air Consumption (CFM): 4, Speed (RPM): 700, Air Inlet Size (in. NPT): 1/4, Min. Hose Size (in.): 3/8, Reversible: Yes, Side Handle: Yes 2-handed ergonomic cushion grip for comfort and control [Read more] Store: Northern Tool and Equipment Brand: Northern Industrial Tools Milwaukee Electric Tool MLW2601-22 M18 18V Compact Driver Drill $283.49 1/2 in. ratcheting chuck with plastic sleeveheavy-duty 2-speed metal gear box: 0-350/0-1 400 rpmcompact length (7-3/4 in.) fits in tight areascompact motor delivers 400 in.-lbs. of maximum torquebuilt-in led light illuminates work surfacesbelt hook frees up both hands for work positioning before fasteninglightweight 4.0 lbs.includes 2 batteries18v lithium-ion charger [Read more] Store: UnbeatableSale.com Brand: Milwaukee Electric Tool Milwaukee Electric Tool MLW5378-20.5" Hammer-Drill with Dual $195.59 trigger speed control reversible. drill with or without hammering action all ball and roller bearings removable side handle self-stopping brushes double insulatedspecifications:amps - 7.0rpm low - 0-1 350rpm high - 0-2 500blows per minute: low - 0-20 000blows per minute: high - 0-40 000length - 13"net wgt. lbs. - 7ship. wgt. lbs. - 8.25 [Read more] Store: UnbeatableSale.com Brand: Milwaukee Electric Tool Makita MAK6013BR 1/2 Inch Drive Heavy Duty Reversible Electric Drill $300.19 features and benefits: rocker type switch for easy one handed forward or reverse operation d-handle rotates 360 degree for multi-position operation ball and needle bearing construction for long tool life and smooth operation heavy duty industrial 1/2" drill chuck for positive bit retention and accurate drilling handy chuck key is retained in handle to prevent loss550 rpm with double gear reduction for added torque. drill includes: top handle (152492-0) and drill chuck (763047-2a). [Read more] Store: UnbeatableSale.com Brand: Makita - Drill Doctor Drill Bit Sharpener - 3/32in. Dia. to 1/2in. Dia. Bits, Model# DD350X $59.99 The Drill Doctor DD350X is a value-priced and easy-to-use drill bit sharpener, ideal for the shop that uses the most common bit styles and works mainly in wood and light metals. U.S.A. Bit Sizes (SAE): 3/32 to 1/2, Angle Sharpening (deg.): 118, Carbide-Tip Bits: Yes, High Speed Steel Bits: Yes, Masonry Bits: Yes, Titanium-coated Bits: Yes Easy front-loading chuck Simplified alignment and sharpening procedures Replaceable diamond sharpening wheel Model DD350X [Read more] Store: Northern Tool and Equipment Brand: Drill Doctor - Powersmith Cordless Drill Kit - 18 Volt, 3/8in. Size, Model# PS0805K $29.99 Volts: 18, Speed - No Load (RPM): 0 - 550, Chuck Size (in.): 3/8, Keyless Chuck: Yes, Clutch Settings: 20, Reversible: Yes, Variable Speed: Yes, Side Handle: No, Battery Included: Yes, (1) 18V battery, Charger Included: Yes, Case Included: Yes Instant-stop electric brake Soft grip handle for control and comfort Includes 6-pc. drill set and 8-pc. screwdriver bit set [Read more] Store: Northern Tool and Equipment Brand: Power Smith - Drill Doctor Drill Bit Sharpener for Split-Point Bits - 3/32in. Dia. to 1/2in. Dia. Bits, Model# DD500X $99.99 The Drill Doctor DD500X is a professional-level drill bit sharpener that is ideal for sharpening a full range of bits, including split points and the 135 bits used in drilling hardened metals. Sharpens split-point bits and creates split-points from standard bits. U.S.A. Bit Sizes (SAE): 3/32 to 1/2, Angle Sharpening (deg.): 118, 135, Carbide-Tip Bits: Yes, High Speed Steel Bits: Yes, Masonry Bits: Yes, Split Point Bits: Yes, Titanium-coated Bits: Yes, Case Included: No Easy front-loading chuck Features Quick Change diamond sharpening wheel Simplified alignment and sharpening procedures E-Z Align System assures correct sharpening alignment Variable Alignment lets you adjust chisel and relief angles [Read more] Store: Northern Tool and Equipment Brand: Drill Doctor Irwin Unibit #4 High Speed Steel Fractional Self-Starting/Hole Enlarging Step Drill Bit, Model# 10234 $39.99 SpeedPoint tip geometry penetrates stainless steel 6 times faster than before. Single-flute design minimizes vibration and controls progression through the drilling steps. U.S.A. Includes (qty.): 1, Hole Size Range: 3/16 - 7/8, Increments (in.): 1/16, Steps: 12 Ideal for drilling holes into thin materials (3/8in. max.) such as stainless steel, copper, brass, aluminum, plastic and laminates New SpeedPoint tip penetrates faster than previous Unibits and prevents walking Single-flute cutting edge for greater control through steps 3 flatted shank prevents slipping in drill chuck Hole size range: 3/16in. - 7/8in. Increments: 1/16in. Number of holes: 12 steps Model 10234 [Read more] Store: Northern Tool and Equipment Brand: Irwin - Makita Compact 18 Volt Li-Ion Hammer Drill/Driver, Model# BHP452HW $227.99 Makitas Compact 18V Li-Ion Hammer Drill/Driver helps you get the job done quickly thanks to quick-charge batteries that wont leave you waiting. Volts: 18, Rated RPM: 0 - 400 / 0 - 1, 500, Torque (in./lbs.): 450 Powerful 4-pole motor delivers 450 in.-lbs. torque Two speeds: 0-400 or 0-1500 RPM 0-6000 or 0-22, 500 BPM Built-in LED Battery recharges in only 15 minutes Compact design, weighs less than 4 pounds [Read more] Store: Northern Tool and Equipment Brand: Makita - Drill Doctor Drill Bit Sharpener for Split-Point Bits - 3/32in. Dia. to 3/4in. Dia. Bits, Model# DD750X $139.99 The Drill Doctor DD750X is a professional-level drill bit sharpener that is ideal for sharpening a full range of bits, including split points and the 135 bits used in drilling hardened metals. Sharpens split-point bits and creates split-points from standard bits. The included large chuck sharpens 3/4in. bits. U.S.A. Bit Sizes (SAE): 3/32 to 3/4, Angle Sharpening (deg.): 115 to 140, Carbide-Tip Bits: Yes, High Speed Steel Bits: Yes, Masonry Bits: Yes, Split Point Bits: Yes, Titanium-coated Bits: Yes, Case Included: Yes Has the flexibility required to sharpen the largest range of drill or broken bits, including HHS, carbide, cobalt-coated, titanium-coated, split points and masonry bits Easy front-loading chuck Permanent magnet motor produces consistent power, regardless of speed or load Features Quick Change diamond sharpening wheel Adjustable Material Take-Off (MTO) touches up dull bits or deep grinds damaged bits E-Z Align System assures correct sharpening alignment Variable Alignment lets you adjust chisel and relief angles [Read more] Store: Northern Tool and Equipment Brand: Drill Doctor

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Therefore, a 1/4-inch-capacity drill is capable of drilling a 1/4-inch diameter hole or smaller in steel. Portable electric and pneumatic drills rated at 1/4 to 1/2-inch maximum capacities are usually equipped with geared drill chucks for mounting straight, round shank twist drills or other similar tools by using a chuck key (Figure 3). Heavier portable drills (Figure 4) having a 3/4- to 1 1/4-inch capacity use taper shank chucks to mount drills and other similar tools.

Fig. 3 - Geared drill chuck and chuck key. - Cabezal portabroca o mandril dentado y llave de ajuste de mandril.

Portable drills have many different characteristics (Figure 5) depending on how the job is to be done. They may be set for one speed or they maybe variable speed drills. A variable speed drill is an excellent tool for use as a power screwdriver.

Portable drills may be equipped with a reversing switch to allow a screwdriver attachment to reverse bolts and screws out of holes. Special 90° angle portable drills (Figure 8) are available for drilling in confined spaces where a standard size drill will not have sufficient clearance. For corners and tight spots, a 360° angle portable pneumatic drill (Figure 2) is available which can be swiveled to any desired angle and locked into position. Most portable drills have a lock button near the on-off switch which allows for continuous operation without holding the trigger. Side handles and rear spade handles (Figure 5) can be attached to most drills to stabilize drilling and to allow for better control. Special devices, such as a vertical stand (Figure 6) or feed screw (Figure 7), can be used on some of the portable drills to make a job easier or more proficient.

Fig. 5 - Common portable drill - Taladro portátil común

The size, type, and power capacity of portable drills selected depends on the job to be performed. Before attempting a drilling job, check the capabilities of the portable drill with the manufacturer's instruction manual .

Fig. 7 - Operation of the portable drill showing the use of the feed screw - Operación del taladro portátil mostrando el uso del tornillo de accionamiento de avance

Por lo tanto, un taladro ¼ pulgadas de capacidad es capaz de perforar un agujero de ¼ pulgada de diámetro o más pequeño en acero. Los taladros eléctricos y neumáticos portátiles clasificados en ¼ a ½ de pulgada de capacidades máximas son generalmente equipados con manguitos porta broca dentados para el montaje de brocas rectas, de espiga redonda u otras herramientas similares usando una llave de mandril (figura 3). Taladros portátiles más pesados (figura 4) que tienen capacidades de ¾ - a 1 ¼ pulgadas usan espiga de forma cónica para montar las brocas y otras herramientas similares.

Fig. 4 - 1 inch capacity portable electric drill - Taladro eléctrico portátil de 1 pulgada de capacidad.

Los taladros portátiles tienen diversas características (figura 5) dependiendo de cómo debe ser hecho el trabajo. Pueden ser ajustados para una velocidad o pueden ser taladros de velocidad variable. Un taladro de velocidad variable es una herramienta excelente para su uso como destornillador eléctrico.

Los taladros portátiles se pueden equipar con un interruptor de inversión para permitir que un accesorio del destornillador destornille pernos y tornillos de los agujeros. Taladros portátiles especiales de 90° de ángulo (figura 8) están disponibles para perforar dentro de espacios confinados donde un taladro de tamaño estándar no tendrá suficiente espacio. Para las esquinas y puntos con poco margen, un taladro neumático portátil de 360° de ángulo (figura 2) está disponible para que se pueda hacer girar sobre un eje a cualquier ángulo deseado y ser trabado en una posición. La mayoría de los taladros portátiles tienen un botón de traba cerca del interruptor de encendido-apagado que permite una operación continua sin accionar el disparador. Los mangos laterales y mangos posteriores tipo espada (figura 5) se pueden fijar a la mayoría de los taladros para estabilizar la perforación y para disponer de un mejor control. Los dispositivos especiales, tales como el soporte vertical (figura 6) o eje de avance (cuadro 7), se pueden utilizar en algunos de los taladros portátiles para hacer un trabajo más fácil o más eficiente.

Fig. 6 - Portable electric drill with vertical stand - Taladro eléctrico portátil con soporte vertical

El tamaño, el tipo, y la capacidad eléctrica de los taladros portátiles seleccionados dependen del trabajo a ser realizado. Antes de intentar un trabajo de perforación, compruebe las capacidades del taladro portátil con el manual de instrucciones del fabricante.

Fig. - Hand drilling operation in confined space using the 90° angle drill - Operación de taladrado manual en espacios estrechos usando el taladro angular de 90°

DRILLING OPERATIONS

Operation of the portable electric and pneumatic drills differs from recommended operating procedures for the upright drilling machine. The portable drill is hand supported for most operations, and the cutting speed of the drill is fixed or dependent upon the operator to control. When hand supported, the drill must be carefully aligned with the workpiece (Figure 9) and this alignment must be maintained throughout the drilling operation. Care must be taken not to lose control of the portable drill and allow it to be wrenched from the operator's hands. The larger portable drills (Figure 10) can be very dangerous if not held firmly by the operator.

Fig. 9 - Drilling with portable drill - Perforando con taladro portátil

If the cutting speed is fixed, the operator must learn to control the feed of the portable drill by applying sufficient pressure for the drill to cut, but not too much pressure as to cause overheating of the twist drill or stalling of the portable drill motor.

When metal is to be drilled with the portable drill, the workpiece must be prepared by locating the center position of the potential hole and marking the location with a center punch. When a large drill is to be used, it will be necessary first to drill a pilot hole slightly larger in diameter than the thickness of the larger drill's web, which will allow for the drag caused by the larger drill's chisel edge (Figure 11).

Fig. 11 - Drilling a pilot hole for a larger drill - Perforando un agujero piloto para una mecha mas grande.

Portable pneumatic drills require special attention to lubricate their internal moving parts. Each drill may be made slightly different, so refer to the pertinent lubrication order or manufacturer's instruction manual before drilling.

For drilling by hand, the workpiece must be mounted securely. Thin workpieces should be backed up with a thicker piece of wood or metal to prevent the drill from snagging in the workpiece. Do not attempt to hold any workpiece by hand or serious injury could result.

Select a twist drill of the proper size for the hole to be drilled. Ensure that the twist drill selected has the right type of shank for the type of chuck mounted on the portable drill.

Taper shank drills cannot be mounted in a drill with a geared chuck. Check each twist drill for sharp cutting edges prior to use.

After securing the twist drill in the proper chuck, connect the portable drill to its power source. Position the portable drill perpendicular to the workpiece and center the chisel point of the drill in the center-punched hole of the workpiece.

Apply firm but not too heavy pressure upon the portable drill, pull the trigger or throttle button to start the drill.

Apply a few drops of cutting oil to the twist drill and hole (Figure 3-12) to improve the cutting action and prevent overheating of the twist drill. For long drilling operations, stop the drill and allow it to cool; then apply additional cutting oil to the drilling area. The lock button can be engaged for lengthy cutting operations.

Continue drilling the hole while applying enough pressure to produce a clean chip, but not so much pressure as to cause the motor to strain or the drill to bind. The drill must be held firmly at all times to prevent the drill from being wrenched from the hands of the operator if the flutes of the drill should snag on a metal burr in the hole.

As the twist drill nears the back wall of the workpiece, release the lock button so that the drill can be stopped immediately if required. Decrease the feed pressure as the drill breaks through, and cautiously feed the drill through the wall of the workpiece. If the drill should snag on a burr, stop drilling immediately and withdraw from the hole. Carefully feed the drill back into the hole while the drill is turning to cut through the burr.

When a portable drill is mounted to a vertical stand, the operating procedure is identical to that used for the upright drilling machine. Use the lock button while drilling and use the hand lever to drill to the required depth.

Portable drilling operations can be difficult to an inexperienced operator. It is difficult to keep the twist drill perpendicular to the workpiece during drilling, and it is hard to drill to a desired depth accurately. If help is available, use the buddy system to keep the drill aligned while drilling. To drill to depth, mark the twist drill with a light colored marking pen or a strip of tape and keep a close watch on the drill as it cuts. Another way to drill to depth accurately using the portable drill is to use a jig, such as a piece of metal pipe or tubing cut to length, to indicate when the drill has reached the desired depth.

Fig. 12 - Drilling lubrication, correct and incorrect - Lubricación de perforación, correcta e incorrecta.

OPERACIONES DE PERFORACIÓN

La operación de los taladros eléctricos y neumáticos portátiles difiere de los procedimientos de funcionamiento recomendados para una perforadora vertical. El taladro portátil es soportado a mano para la mayoría de las operaciones, y la velocidad de corte del taladro es fija o dependiente del control del operador. Cuando se soporta a mano, el taladro debe alinearse cuidadosamente con la pieza de trabajo (figura 9) y esta alineación debe mantenerse a lo largo de la operación de perforación. Se debe tener cuidado de no perder el control del taladro portátil para no permitir que se tuerza en las manos del operador. Los taladros portátiles más grandes (figra 10) pueden ser muy peligrosos si no se sostienen firmemente por el operador.

Fig. 10 - Drilling with a large portable drill - Perforando con un taladro de gran tamaño

Si la velocidad del corte es fija, el operador debe aprender a controlar la alimentación del taladro portátil aplicando la suficiente presión para que el taladro corte, pero no demasiada presión que cause un recalentamiento del taladro de mecha helicoidal o el atasco del motor portátil del taladro.

Cuando el metal debe ser perforado con el taladro portátil, la pieza de trabajo debe ser preparada ubicando la posición central del agujero en cuestión y marcando la localización con un punzón central. Cuando un taladro grande debe ser utilizado, será necesario primero perforar un agujero piloto levemente más grande en diámetro que el grueso del filo de mecha más grande, que permitirá que se produzca la fricción causada por el borde biselado de la broca más grande (figura 11).

Los taladros neumáticos portátiles requieren especial atención para lubricar sus piezas móviles internas. Cada taladro puede hacerse ligeramente diferente, por lo tanto refiérase a la orden correspondiente de instrucciones o al manual de lubricación del fabricante antes de perforar.

Para perforar a mano, el objeto se debe montar con seguridad. Las piezas de trabajo finas se deben sostener con un pedazo más grueso de madera o de metal para evitar el desrebabado de taladro en el objeto. No intente sostener ningún objeto a mano o una lesión seria podría resultar.

Seleccione un taladro de broca helicoidal del tamaño apropiado para que el agujero sea perforado. Asegúrese de que el taladro seleccionado tenga el tipo correcto de espiga para el tipo de mandril montado en el taladro portátil.

Los taladros de espiga de forma cónica no se pueden montar en un taladro con un mandril de engranajes. Compruebe el filo de cada mecha helicoidal antes de su uso.

Después de asegurar la mecha helicoidal adentro del mandril apropiado, conecte el taladro portátil a su fuente de energía. Coloque el taladro portátil perpendicular al objeto de trabajo y centre el punto biselado de la mecha en el agujero de centrado perforado en el objeto. Aplique una presión firme pero no excesiva sobre el taladro portátil, tire del botón del disparador o del botón de traba para encender el taladro.

Aplique algunas gotas de lubricante para cuchillas a la mecha helicoidal y al agujero (figura 3-12) para mejorar la acción de corte y para prevenir el recalentamiento de la mecha. Para las operaciones largas de perforación, pare el taladro y permita que se enfríe; luego aplique lubricante para cuchillas adicional al área de la perforación. El botón de bloqueo se puede accionar para operaciones muy largas de corte.

Continúe perforando el agujero mientras que aplica bastante presión para producir una viruta limpia, pero no tanta presión para hacer que el motor se sobrecargue o que la mecha se doble. El taladro se debe mantener firmemente siempre, para evitar que el mismo se desprenda de las manos del operador si las ranuras de la mecha se encastraran en las rebabas del metal en el agujero.

A medida que la mecha helicoidal se acerca a la pared trasera del objeto de trabajo, libere el botón de bloqueo para poder parar el taladro inmediatamente si es necesario. Disminuya la presión del proceso de taladrado a medida que la mecha pasa, y accione cautelosamente el taladro a través de la pared del objeto. Si el taladro se encastra en las rebabas, pare el perforar inmediatamente y retírese del agujero. Cuidadosamente inicie el proceso de taladrado nuevamente dentro del agujero mientras que la mecha está girando para cortar a través de las rebabas.

Cuando un taladro portátil se monta sobre un soporte vertical, el procedimiento de funcionamiento es idéntico a aquel usado para la perforadora vertical. Utilice el botón de bloqueo mientras que perfora y utilice la palanca de mano para perforar a la profundidad requerida.

Las operaciones de perforación con taladro portátil pueden ser difíciles para un operador inexperto. Es difícil mantener la mecha helicoidal perpendicular al objeto durante la perforación, y es difícil perforar a una profundidad deseada con precisión. Si la ayuda está disponible, recurra a un ayudante para mantener el taladro alineado mientras se perfora. Para perforar en profundidad, marque la mecha helicoidal con un marcador de color claro o un trozo de cinta y mantenga estrecha vigilancia al taladro a medida que corta. Otra manera de perforar en profundidad con precisión usando un taladro portátil es utilizar una plantilla, tal como un pedazo de cañería o de tubería de metal cortada a medida, para indicar cuando el taladro ha alcanzado la profundidad deseada.