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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Powersmith Cordless Drill Kit - 18 Volt, 3/8in. Size, Model# PS0805K $29.98 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] Brand: Power Smith Tanaka Gas-Powered Drill - 1.3 HP, 1/2in. Chuck, Locking, Model# TED-262L $469.98 HP: 1.3, Engine Displacement (cu. in. (cc)): 26, Rated RPM: 0 - 450, Chuck Size (in.): 1/2, Gear Ratio: 20:1 2-cycle engine (50:1 gas/oil ratio) Features a locking mechanism for manually backing out a bit Recoil start; electronic ignition Chrome-plated cylinder Forged steel connecting rod Walbro diaphragm carburetor with primer Heavy-duty centrifugal clutch system CARB Tier II and EPA Phase 2 compliant [Read more] Brand: Tanaka Milwaukee M12 Cordless Right Angle Drill/Driver Kit - Tool Only, 3/8in, Model# 2415-20 $99.98 The Milwaukee M12 Cordless Right Angle Drill/Driver features a head size of only 3 3/4in. yet delivers 100 in-lbs. of torque in a compact lightweight design. The first sub-compact right angle drill driver with a spindle lock chuck, the 2415-20 is the most versatile right angle drill/driver in the industry. Built-in electronics include an electronic clutch, fuel gauge, variable speed control and overload protection. Item is on backorder until early May. Max. Torque (in-lbs.): 100, Volts: 12, Speed - No Load (RPM): 0-800, Chuck Size (in.): 3/8, Keyless Chuck: Yes, Clutch Settings: 11, Reversible: Yes, Variable Speed: Yes, Side Handle: No, Battery Included: No, Case Included: No, Tool Length (in.): 11.5, Tool Weight (lbs.): 2.03 Tool only; battery sold separately 3/8in. single-sleeve ratcheting chuck for maximum versatility and grip 3 3/4in. head length is ideal for working in tight spaces Extended paddle switch provides convenience and comfort Electronic clutch features 11 settings plus drill mode for complete control Built-in LEDs illuminate work surface and indicates clutch out Battery fuel gauge displays remaining run time [Read more] Brand: Milwaukee DEWALT Heavy-Duty Cordless Right Angle Drill/Driver Kit - 12 Volt, 3/8in, Model# DW965K-2 $199.99 The DEWALT Cordless Right Angle Drill/Driver offers two speed ranges (0-400/0-1,200 RPM) for increased user flexibility and a wider range of applications. 180 in-lbs. of maximum torque gets heavy-duty jobs such as turning large bits and fasteners completed fast. Multi-grip trigger provides comfort and convenience for use in tight spaces. Durable, right angle transmission with sealed ball bearing provides a longer tool life. Max. Torque (in-lbs.): 180, Volts: 12, Speed - No Load (RPM): 0 - 400 / 0 - 1,200, Chuck Size (in.): 3/8, Keyless Chuck: Yes, Reversible: Yes, Variable Speed: Yes, Side Handle: No, Battery Included: Yes (2), Charger Included: Yes, Case Included: Yes, Tool Weight (lbs.): 4.1 Plastic, 2-sleeve chuck 65 Unit Watts of maximum power for heavy-duty applications such as turning large bits and fasteners Variable speed and reversing gives the user the ability to control speed for greater accuracy, and the convenience of reverse [Read more] Brand: Dewalt Milwaukee Reconditioned Drill - 3/8in, 8 Amp, Model# 0240-80 $49.99 The Milwaukee corded drill features a powerful 8.0 Amp motor and 0-2800 RPM, giving you the power to perform even the toughest applications. Durability standard with an all metal gear case that protects the gears and provides superior support in high torque applications. Perfect for metal drilling, wood drilling and fastening applications. This Drill is factory reconditioned to perform like new. NorthernTool. com offers reconditioned tools and equipment that are equal to the standards and quality of new products, yet give you the same features at considerable savings. This model is warranted for 12 months parts and labor; Service Protection Plan available. Amps: 8.0, Chuck Size (in.): 3/8, Speed (RPM): 0-2,800, Cord Length (ft.): 8, Side Handle: Yes, Keyless Chuck: Yes, Variable Speed: Yes, Case Included: No Soft-grip handle and 2-finger trigger for added comfort [Read more] Brand: Milwaukee Chicago Pneumatic Air Drill - 3/8in, 2400 RPM, 4 CFM, Model# CP785 $149.99 This Chicago Pneumatic 3/8in. air drill features a powerful energy-efficient air motor to resist stalls. Ideal for accessory and air conditioner installation, engine work and auto body repair. Chuck Size (in.): 3/8, Keyless Chuck: No, Air Consumption (CFM): 4, Speed (RPM): 2,400, Air Inlet Size (in. NPT): 1/4, Min. Hose Size (in.): 3/8, Variable Speed: Yes, Reversible: No, Side Handle: 2 1/4, Tool Weight (lbs.): 7 Versatile drill for a variety of automotive service and body shop applications Triple Idler Planetary Gearing for smooth operation and long life Rugged 1/2 HP motor Handle exhaust directs air away from operator Ergonomically designed handle for operator comfort [Read more] Brand: Chicago Pneumatic Milwaukee Magnum Electric Drill - 1/2in. Chuck Size, 850 RPM, 5.5 Amp, Model# 0234-6 $144.99 This heavy duty Magnum drill is built for industrial/construction applications. It features raw power with a Milwaukee built 5.5 amp motor, and a Quik-Lok cord that can be quickly removed from the drill for storage or service replacement. Another exclusive feature is the brush cartridge system, with a set of spare brushes, that allows you to change brushes in less than one minute. Use this tool with a variety of accessories to drill into wood, metal, plastics and composites. U.S.A. Amps: 5.5, Chuck Size (in.): 1/2, Speed (RPM): 850, Cord Length (ft.): 8, Side Handle: Yes, Keyless Chuck: No, Variable Speed: Yes, Case Included: No Trigger speed control with reverse Magnum system gives you the power you need Model 0234-6 [Read more] Brand: Milwaukee Northern Industrial Floor Drill Press - 16-Speed, 3/4 HP $229.99 Power, accuracy and versatility, this floor drill press has it all. HP: 3/4, Volts: 120, Speed (RPM): 250-3100, Speeds (qty.): 16, Vertical Stroke: 3 11/64in, Swing: 13in, Drilling Capacity (in.): 5/8, Chuck Size (in.): 5/8, Worktable L x W (in.): 10 x 10, Dimensions L x W x H (in.): 9 x 22 13/16 x 63 1/3 Depth lock Spindle taper: MT-2 Screwdriver handle 17 15/16in. x 10 5/8in. base [Read more] Brand: Northern Industrial Tools 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] Brand: Makita Milwaukee M12 Cordless Drill/Driver - 12 Volt, 3/8in, Model# 2410-22 $159.99 The Milwaukee M12 Drill/Driver has the power to drive the majority of common small fasteners, and the run time of full day screw driving without recharging. The compact size allows the users to work in tight places for increased convenience. Max. Torque (in-lbs.): 250, Volts: 12, Speed - No Load (RPM): 0 - 400 / 0 - 1,500, Chuck Size (in.): 3/8, Keyless Chuck: Yes, Clutch Settings: Yes, Reversible: Yes, Variable Speed: Yes, Battery Amp/Hour: 1.4, Battery Included: Yes (2), Charger Included: Yes, Case Included: Yes, Tool Length (in.): 7 3/8, Tool Weight (lbs.): 2.5 Heavy-duty 2-speed metal gearbox Single-sleeve metal chuck Li-Ion batteries for extended run time Built-in LED worklight Battery fuel gauge [Read more] Brand: Milwaukee DEWALT Cordless Drill/Driver - 18 Volt XRP, 1/2in. Chuck, Model# DCD940KX $279.98 The DEWALT cordless 18V 1/2in. drill / driver is designed to handle all your drilling and fastening tasks. Powerful drill features 3 speed ranges, a built-in LED light and heavy-duty ratcheting chuck. Operates on XRP batteries for extended run times. Volts: 18, Speed - No Load (RPM): 0 - 500 / 0 - 1,250 / 0 - 2,000, Chuck Size (in.): 1/2, Keyless Chuck: No, Clutch Settings: 22, Reversible: Yes, Variable Speed: Yes, Side Handle: Yes, Battery Included: Yes, (2) 18V XRP batteries, Charger Included: Yes, 1 Hour, Case Included: Yes, Tool Weight (lbs.): 6.25 Patented 3-speed all-metal transmission matches the tool to task for fastest application speed and improved run time Heavy-duty 1/2in. ratcheting chuck helps prevent bits from slipping and falling out LED worklight provides increased visibility in confined spaces High power, high efficiency motor delivers 450 watts of max power for superior performance in all drilling and fastening applications XRP extended run-time batteries provide long run-time & battery life [Read more] Brand: Dewalt Northern Industrial Mini Drill Press - 5-Speed, 1/3 HP $84.98 Mini drill press lets you drill with accuracy. HP: 1/3, Volts: 120, Speed (RPM): 620-3100, Speeds (qty.): 5, Vertical Stroke: 2in, Swing: 8in, Drilling Capacity (in.): 1/2, Chuck Size (in.): 1/2, Worktable L x W (in.): 6 5/8 x 6 9/16, Dimensions L x W x H (in.): 7 x 16 15/16 x 22 1/2 Threaded depth lock Screwdriver handle 11 5/8in. x 7 1/3in. base [Read more] Brand: Northern Industrial Tools DEWALT Compact Cordless Drill/Driver Kit - 18 Volt, 1/2in, Model# DCD760KL $219.99 The DEWALT Compact Cordless Drill/Driver has a lightweight design to minimize user fatigue, as well as a compact size to allow users to fit into tight spaces. Dual speed range delivers optimal performance. LED work light provides increased visibility in confined spaces. Max. Torque (in-lbs.): 350 UWO, Volts: 18, Speed - No Load (RPM): 0 - 500 / 0 - 1,700, Chuck Size (in.): 1/2, Keyless Chuck: Yes, Clutch Settings: 17, Reversible: Yes, Variable Speed: Yes, Battery Included: Yes (2), Charger Included: Yes, Case Included: Yes, Tool Weight (lbs.): 4 [Read more] Brand: Dewalt Tanaka Gas-Powered Drill - 1.3 HP, 1/2in. Chuck, Reverse Lever, Model# TED-270PFR $549.98 HP: 1.3, Engine Displacement (cu. in. (cc)): 26, Rated RPM: 0 - 450, Chuck Size (in.): 1/2, Gear Ratio: 20:1 2-cycle engine (50:1 gas/oil ratio) Reverse lever Recoil start; electronic ignition Chrome-plated cylinder Forged steel connecting rod Walbro diaphragm carburetor with primer Heavy-duty centrifugal clutch system CARB Tier II and EPA Phase 2 compliant [Read more] Brand: Tanaka Makita Reconditioned Cordless Drill/Driver - Tool Only, 14.4-Volt, 1/2in. Chuck $39.99 The Makita Reconditioned 14.4V Cordless Drill/Driver delivers 450 ft-lbs. of max. torque for heavy-duty drilling and fastening applications. Works with either Ni-MH or Ni-Cd 14.4V Makita batteries. Tool only; battery, charger and case not included. This cordless drill/driver is factory reconditioned to perform like new. NorthernTool. com offers reconditioned tools and equipment that are equal to the standards and quality of new products, yet give you the same features at considerable savings. Volts: 14.4, Speed - No Load (RPM): 0-300, 0-600, 0-1,700, Chuck Size (in.): 1/2, Keyless Chuck: Yes, Clutch Settings: 16, Reversible: Yes, Variable Speed: Yes, Side Handle: No, Battery Included: No, Charger Included: No, Case Included: No 450 ft-lbs. of max. torque 3 speed ranges: 0-300, 0-600, 0-1700 RPM 2-pc. motor with dual ball bearings for longer motor life 16 torque settings plus drill mode Ergonomic design Works with either Ni-MH or Ni-Cd 14.4V Makita batteries Tool only; battery, charger and case not included Factory reconditioned to perform like new [Read more] Brand: Makita Kawasaki 20-Pc. Cordless Drill Kit - 19.2 Volt, 3/8in. Chuck, Model# 840110 $59.99 Powerful 19.2 volt cordless drill includes an assortment of drill bits, drive bits and a couple of batteries to keep you working while one battery is charging. Volts: 19.2, Speed - No Load (RPM): 400 / 1,100, Chuck Size (in.): 3/8, Keyless Chuck: Yes, Clutch Settings: 25, Reversible: Yes, Variable Speed: Yes, Side Handle: No, Battery Amp/Hour: 1.3, Battery Included: Yes, (2) 1.3Ah batteries, Charger Included: Yes, Case Included: Yes ABS body Aluminum gear housing Electric brake Bubble level on drill Ergonomic anti-slip soft grip handle Includes 6 high speed drill bits (3/32in, 1/8in, 5/32in, 3/16in, 7/32in, 1/4in.), 8 drive bits (Phillips #1-3; slotted 1/4in, 3/16in, 1/8in.), and bit holder [Read more] Brand: Kawasaki

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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.