Image source: Jergens, Inc. | Rogan Corporation | Allied Electronics
Industrial knobs are small, usually round, devices that are designed for use on industrial machinery, electronic components, and metal cabinetry.
Industrial Knobs - How They Work
Knobs are projecting parts, of various shapes and sizes, used to facilitate the mechanical operation of levers, instruments, drawers, and other devices. Industrial knobs are manufactured for a variety of applications, including medical handles, construction equipment, instrumentation and control, and food processing.
Industrial knobs are generally designed based on the torque requirements of their intended application. Torque refers to the force required to rotate an object, in this case a lever or other control device, about its axis. Some knobs (such as ball knobs) are manufactured for hand-actuated low torque use, while others (such as t-handle knobs) are designed for accurate control in high torque applications.
The GlobalSpec SpecSearch database contains information about numerous types of industrial knobs.
Ball knobs are spherical in shape and are suitable for low torque directional (up-down or left-right) motion. They are commonly used on levers or shafts in applications such as process control or hydraulic system regulation.
Bar knobs refer to a wide range of products which can be first tightened by hand, then further tightened using a small bar. They are well suited to heavy duty applications and are manufactured in a variety of shapes and designs. The example knob below contains four raised prongs; after the knob is tightened by hand, the bar is inserted horizontally between the prongs and turned for additional tightness.
An example of a bar knob. Image credit: Jergens, Inc.
Torque knobs provide clamping force necessary for adjustable devices and machinery such as camera tripods, lawnmower handle releases, and machine tool adjusting devices. The desired torque of adjustable torque knobs can be set in advance with a wrench. These knobs can turn freely in one direction when the desired torque is reached, but remain locked in the other direction for added security.
Fluted knobs are round knobs with grooves cut into the knob edges. The groove pattern, known as fluting, provides extra grip and stability when turning the knob. Fluted knobs are typically used in a wide range of medium torque applications.
An assortment of fluted knobs. Image credit: Dimco Gray
Control knobs are used for the control or adjustment of electronic or electrical devices, and are often referred to as instrument knobs, electronic knobs, or electrical knobs. Control knobs provide machines or instruments with precise position adjustments and controlled levels of circular motion.
Lever knobs come in a wide variety of shapes and sizes and are used on gearshifts, levers, crank handles, and power tools.
Push/pull knobs are constructed with a tapered shank to provide sufficient grip for pulling, as well as an enlarged head to facilitate easy pushing. They are often used as drawer pulls or lid knobs.
An assortment of push-pull knobs. Image credit: Dimco Gray
Spinner knobs are large, round knobs with flat heads. They are designed to be easily turned with one hand and may include a small handle for additional ease of turning.
Lobed knobs are ideal for applications requiring precise control and high torque. A lobed knob may have anywhere from two to six lobes or arms which protrude from its sides. Lobed knobs are known by a variety of names, depending on the number of lobes.
Two lobes: t-handle knob, wingnut knob
Three lobes: trigon knob
Four lobes: hand knob
Five lobes: star knob
A group of t-handle or wingnut knobs. Image credit: Dimco Gray
Industrial knobs may feature one or more of several different mounting styles.
The knob may include a bushing inserted into the bore to refine the bore size or resist abrasion.
A control knob set featuring a brass bushing. Image credit: RickySounds
A knob with collet mounting consists of an outer body with internal hardware. This internal hardware includes a collet, which is a sleeve with a cylindrical inner surface and a conical outer surface. When the collet is squeezed against a matching tapered stud, it contracts and creates a secure clamping hold on the stud. Collet mount knobs must be installed with a nut driver.
Disassembled knobs with collet mounting. Image credit: Selco
Panel mount knobs are mounted to the flat surface of a panel cutout using screws.
Stud mount knobs use a projecting stud, usually threaded, for mounting.
Threaded hole knobs feature a threaded bore which can be screwed onto a similarly threaded stud. In a thru hole mounted knob, the threaded hole extends through the entire height of the knob and is secured by a counter bore at the top.
An industrial knob may feature a number of enhancements to its basic construction and shape.
Angle mount knobs can be mounted at any fixed angle, typically between 0 and 90°.
Knobs may feature textured grips, typically rubber, for increased handling.
Illuminated knobs are lit for improved visibility in low-light conditions.
Some knobs feature an indicator or pointer, which is a line or dot on the top or side of the knob. Knobs may additionally feature a numerical scale for position indication.
Knobs may be knurled to improve grip and handling. Knurling on a lathe cuts a pattern into the sides of the knob to accomplish this benefit.
Latching knobs have the capability to hold the knob in position.
Locking knobs prevent the knob from being moved without action by the operator. They may be unlocked with a pushbutton or key.
Skirted knobs flare out at the bottom and may be marked with a numerical scale or indicator.
A knurled, skirted control knob featuring a pointer. Image credit: Keystone Electronics Corp.