High Torque Drills
High torque drills are basically low-geared rotary drills that are hence capable of producing a large mount of torque. This huge turning force enables them to perform tasks such as mixing paint and plaster, and boring huge holes through wood and thick metal.
For dedicated mixing applications, mixer drills are also available. These drills generally have two handles, two gears, and a threaded connection (typically 5/8” or M14) to attach long specialised mixing paddles.
High torque drills feature many different components, and having a sound understanding of these plays an important part in the purchasing process. Knowledge of these parts also aids in the efficient and effective use of the tool.
The power source is the component that provides the tool with electricity. On high torque drills, this is done through a wired connection to a mains power supply. In Australia, high torque drills operate off mains power (240V) through a 10A socket.
The switch allows the electricity from the power source to flow through the tool. All portable drills are activated by a trigger switch. When this trigger is pressed, the drill will begin to operate.
The most common type is the variable speed trigger. The further you depress this trigger, the faster the drill will rotate.
On some drills, a small dial in the middle of the trigger controls the variable speed. This construction allows for more accurate speed selections.
This button can be pushed while the trigger is depressed and the trigger will lock on to that set speed. To cease this function, simply pull the trigger.
Make sure this button has been released prior to disconnecting the tool. If not, the tool will begin to operate upon reconnection and may result in injury. For more safety recommendations, click here.
With a flick of this switch, the drilling direction changes to allow for forward and reverse motion (right and left motion respectively). This feature is found on most drills, and can be very helpful if you need to remove screws, or if you need to release your drill bit after it has jammed in the hole.
If flicked between forward and reverse in a neutral position, it also locks the switch to prevent accidental operation of the tool.
You should never change the direction of drive whilst the tool is still operating, as it is highly likely you will damage the tool’s gears.
Motors are the main component of all power tools, and are the component that converts the electricity into motion. The power that motors produce is measured in Watts (W). Motors used in portable electric drills are called AC motors (they are also known as universal or series motors).
These drills are quite hefty, weighing in between about 2 and 3 kilograms. This is mainly due to their large motors, some having an input power of up to 1100W.
Many manufacturers will state only the input power of the drill, as this is the larger and more impressive number. This value is actually just an indication of the demand a tool will place on a power outlet under normal operating conditions. The power output at the chuck, though, is significantly less than the input power. This is due to the efficiency of the drill’s internal components, and how power is transferred through the machine. Generally speaking, higher quality tools have greater efficiency and require less input power to produce the same power output. Therefore, although it is uncommon for most manufacturers to include a power output value, it is a much better way of comparing tools.
Also known as a gearbox, transmissions dictate the speed range (revolutions per minute, or rpm) that a drill can operate at, and the corresponding torque (or turning force) that it can produce.
Transmissions can contain single or multiple gears that are driven by the motor. If a small gear is used in the transmission, then rotary speed will be high but torque will be quite low. If a large gear is used, then rotary speed will be quite low, but torque will be high.
Electric drill accessories come in many different sizes, and all have a recommended speed that they have been designed to operate at. To accommodate these requirements, you must have a drill that has both enough torque and enough speed to handle the accessory.
To acknowledge this fact, manufacturers will state the maximum drilling capacities that a drill is capable of drilling into various materials.
Most heavy-duty high torque drills can bore holes of up to 40mm diameter in wood, 20mm diameter in metal, and can operate a mixing bit up to 160mm diameter.
The optimum drilling capacities of drills are where they will deliver their best performance. If you halve the drill’s maximum drilling capacity, it will give you the optimum drilling size, and is the size of hole you should be most frequently drilling with that drill.
As has been mentioned, these drills are geared for torque and not speed. Some have very slow but powerful triple reduction gearboxes that do not surpass 600/min (revolutions per minute, rpm). This must be taken into account when using particular accessories, some of which require a higher speed to perform correctly.
The chuck is the part of the drill that grips drilling accessories. The transmission powers the drive shaft and on the end of this shaft is the chuck. On high torque drills, there are two types of chucks – keyed and keyless.
Keyed chucks have a solid metal construction – which makes them very durable through excessive vibrations and dust – and are operated by a chuck key. When fitted to the chuck, the chuck key fits into the gear notches of the chuck. As you turn it, it either loosens or tightens the chuck (depending on the turning direction).
It is a good idea to use the chuck key on all three notches of the chuck to ensure each jaw is securely tightened.
Keyless chucks are much faster to use, and can be operated completely by hand. Depending on the quality and purpose of the drill, these chucks can be plastic or metal, or a combination of the two, and usually have a front and rear sleeve. To loosen/tighten the chuck manually, place one hand on the rear sleeve of the chuck and turn the front sleeve right/left. To do this with the aid of the drill, hold the front sleeve of the chuck while you apply some reverse/forward acceleration to the drill.
Some higher quality keyless chucks will also have a locking and/or ratcheting feature when you tighten them so the chuck will never come loose during operation.
Depending on the size and model of the high torque drill, they will either have a 13mm (1/2”) keyless or keyed chuck. If the chuck is keyless, it is very common for the chuck to be partly or wholly made up of metal. This makes for a more robust chuck, and one that can deal with the power that these drills exhibit.
The housing of a drill is the casing that protects the internal components.
High torque drills will have either a clamshell housing, or a jampot housing.
A clamshell housing is where the housing is manufactured in two plastic halves, and where these halves are fixed together around the internal components.
A jampot housing is where the internal components of the drill are inserted into the housing and then a lid (usually an alloy casing) is screwed down to seal it. This durable style of housing is generally used on high quality power tools, and is much more effective at keeping the internal components aligned and the power tool structurally sound.
Most of these drills will have an aluminium gearbox housing (as part of a jampot housing), to allow for efficient dispersion of heat from the drill’s internals. This is especially important in high torque drills, as the applications they are made to perform are generally very demanding.
The handle is the component of the drill that you hold with your dominant hand and is what you use to apply pressure to the drill. On high torque drills, the handle is either a spade handle or a pistol-grip handle.
A spade handle is capable of rotating 360° and gives users greater control over a variety of drilling and mixing applications.
A pistol-grip handle is a standard drill handle you hold more-or-less like a pistol. Some models will have a finger mould toward the top of the handle for your thumb and index finger. This feature allows you to apply forward pressure in a more efficient manner, by pushing in line with the drive shaft and chuck. The pistol grip handle is commonly partially covered by rubber for user-comfort too.
This handle is designed to stop rotation and to provide stability for the user. It is secured just behind the chuck and can be positioned at various angles to the body. The angle is generally changed by unscrewing the handle, moving it, and screwing it back up.
When purchasing a high torque drill, decide what features are most important to you (from the features above) and make sure these are included in your final purchase. The main considerations you should make include how much power you require, the size and weight of the tool, and how often you will be using it.
A high torque drill should have a solid, heavy duty construction, and be able to effortlessly power through the largest of drilling tasks.
Manufacturers will either direct their products at the DIY or professional market. DIY tools are designed for home use and generally include plenty of features for a very modest price. They also tend to have very generous warranty periods, including replacement warranties. Professional tools are designed for commercial use and are built for durability, performance, and reliability. Their warranty periods tend to be much shorter than DIY tools, and are exclusively repair warranties. The main advantage of these tools is that they should well outlive their warranty period, and if they require repair and maintenance spare parts are readily available.
The price of any tool will depend on the quality, capabilities, and features of the model. Bear in mind that at least one of these three elements is commonly sacrificed by manufacturers to reduce the tool’s price and increase its sales. After all, price is the most important factor for consumers.
High torque drills can cost anywhere from $75 to $600.
Mixer drills are typically more expensive, ranging in price from $100 to $1500.
It is important to bear in mind that the entire cost of any power tool is not just it’s initial purchase cost. Added costs can include accessories for the tool to function, maintenance, downtime, and replacement costs. Buying according to your requirements will help to keep these costs to a minimum.
The following tips will help to preserve the life of your high torque drill, increase your efficiency, and most importantly, keep you safe.
Personal protective equipment (PPE) must always be worn when operating power tools. For more information on PPE and power tool safety, click here.
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