What are the parts of a hand drill?

29th February 2020


What are the parts of a hand drill?


	The latest prices for hand drills and braces




		Main handle
		The main handle is at the end of the drill and is used to hold and position the tool and apply pressure to the drill bit in contact with the workpiece. On some models, the main handle can be unscrewed from the rest of the drill. This allows the user to replace a damaged handle or swap a handle for a breast plate (see bottom of page). Some models have a hollow replaceable handle that can be used to store drill bits in.

		Turning handle
		The turning handle is used to rotate the drive wheel, which turns the pinion and spins the drill bit.

		Drive wheel
		The drive wheel is a large gear on the side of the hand drill. As the drive wheel is rotated by the connected turning handle, it in turn spins the pinion gear.

		Pinion
		The pinion or pinion gear has teeth that interlock with the teeth of the drive wheel. As the drive wheel rotates, the pinion transfers the rotation from one axis (direction) to another. This new rotational direction is passed onto the drill bit.

		Frame
		The frame of a hand drill is simply a means of holding the pinion and drive wheel in the correct position to interlock, allowing the drill to function.

		Idle gear
		The idle gear looks exactly the same as the pinion gear and sits at the opposite end of the drive wheel. Its purpose is to balance out the drill by supporting the drive wheel at the opposing end to the pinion gear. The idle gear rotates freely, and does not contribute towards turning the drill bit.

		Chuck
		The chuck is located at the end of the drill and is used to secure or release the drill bit from the jaws of the chuck. The jaws of the chuck close around the shank of the drill bit and hold it in place. For more information see our page What is a chuck and how does it work?

		Jaws
		Hand drills can have either two, three or four jaws within the chuck. By rotating the chuck, the jaws can be brought together, clamping a drill bit, or moved apart, releasing the drill bit.

		Other possible parts
		Ratchet Some hand drills may feature either a 3 or 5 way ratchet. The ratchet allows the turning handle and drive wheel to be rotated in one direction without it turning the drill bit. This can be very useful when drilling in confined spaces that do not allow a complete turn of the turning handle. Instead of turning the handle in a complete circle, the ratchet enables the handle to be moved back and forth through small arcs and will only turn the drill bit when the handle is rotated in the correct direction.



		Side handle Some hand drills have another handle on the opposite side to the turning handle. This can sometimes give the user more control of the hand drill. These side handles can usually be unscrewed from the drill should they make the drill too big for use in confined spaces.

		Breast plate The breast plate can be used in place of the main handle. It allows the user to press down on the drill with their chest. Models fitted with a breast plate are often labelled ‘heavy duty’, as the extra pressure that can be applied with a breast plate helps when drilling into hard materials such as metal.

		Double pinion Hand drills with a double pinion have a second pinion gear that connects to a second ring of teeth at the centre of the drive wheel. Hand drills with double pinions will rotate more smoothly and make drilling easier.

		Oil holes Some hand drills have dedicated oil holes for lubricating the pinion gears and ratchet mechanism. By applying oil to the oil holes, moisture is kept out, preventing corrosion of the gears. The oil also lubricates the gears, reducing wear between them and so extends the life of the hand drill. For further information see our page: Hand drills and braces maintenance and care

		Speed selector Some hand drills feature a speed selector. This is normally found in one of three places on the hand drill; where the turning handle connects to the drive wheel, just in front of the ratchet mechanism, or just behind the chuck. The speed selector works like the gears on a bike, enabling the user to increase the speed the drill bit turns, for the same input speed of the turning handle and drive wheel.

		The speed selector allows the user to switch between a high speed, low torque setting, and a low speed, high torque setting. High speed, low torque should be used when drilling small diameter holes into hard material, whereas low speed, high torque is better suited to drilling large diameter holes.

		Drill bit The drill bit is the part of the hand drill that makes contact with the workpiece and drills the hole. Drill bits are a removable part of the hand drill that can be changed for another drill bit of a different size in order to drill holes of varying diameters.