Industrial knobs are small, usually round, devices that are designed for use on industrial machinery, electronic components, and metal cabinetry. They are usually made out of metal, plastic, or rubber and are available in a variety of sizes, colors, and finishes. Some industrial knobs are knurled or included a textured, rubber grip for positive handling. Others include an integral skirt and provide a numerical scale or indicators with dots, lines, or arrows. Illuminated knobs are well-suited for low-light applications. Devices with latches can be secured in position and do not require the use of a key. Knobs with locks are designed to prevent unauthorized use. Industrial knobs that meet U.S. military specifications (MIL-SPEC) are also available.
There are many types of industrial knobs. Adjustable knobs provide positive, repeatable clamping force and lock for positive retraction. Ball knobs are often used with manually-actuated lever and shafts. Bar knobs are turned by hand, manually tightened, and then tightened again by inserting a bar between the prongs. Clamping knobs are used in valve controls and to adjust machine tools. Instrument knobs are designed for electric and electronic equipment. Ergonomic and multi-functional lever knobs are available in a wide variety of shapes and sizes. Push/pull knobs have enlarged heads and tapered shanks for pushing, pulling, or lifting. Spinner knobs have a flat head and handle, or a hole that allow users to spin the knob with one finger. Thumbscrew knobs are tightened by thumb. Industrial knobs with two to six arms and lobes are commonly available. Three-armed or triangular devices are known as trigon knobs. Other types of industrial knobs include pushbutton knobs and mushroom knobs.
Mounting specifications for industrial knobs include bore diameter and mounting style. Bore diameter is the inside diameter (ID) of the insert, or the outside diameter (OD) of the stud. Mounting styles include bushings, collets, molded threads, threaded holes or inserts, push-on or plain holes, and through holes with counter bores. Bushings are inserted into bores to limit the size of the opening, resist abrasion, and serve as a guide. Collets consist of an outer body and internal hardware that grips the shaft 360° to ensure a secure fit. Collets are installed with a nut driver and require a separate top cap. Industrial knobs that contain a threaded insert or have threads molded into the bore opening are also available. Push-on devices feature a plain hole as a bore. With through hole or counter-bore mounting, the hole extends through the height of the handle and is accompanied by a counter bore on top.