Engineering Tips:

 
Selecting the Correct Knob
 
 
 

No machine component seems more elementary than a knob. But in fact, there are many possible configurations for this simple part, and choosing the right type is key to the optimal function of the machine.

Let's review a dozen or so styles of knobs and their advantages and disadvantages, so you can select the best type for your application.

Ball knobs: Use these for applications that require movement in any and all directions. These types of knobs are comfortable to grip. They are also easy to clean, but don't use them for situations involving moisture or grease; they become too slippery to handle. Shown here is our DIN 319-ST metric size steel ball knob, available in tapped or blind bore types. DIN 319-ST
GN 563.2 T-handle knobs: The design of these knobs gives them strong control, in both in-and-out operations and rotating ones. Likewise, they can achieve strong clamping force. If your application involves a limited space where only one hand can reach, these knobs work well. (However, sometimes a prong knob is preferable, if there is the possibility of the operator being at an awkward angle.) Shown is J.W. Winco's GN 563.2 metric size aluminum T-handle knob, available in tapped or blind bore types.
Mushroom knobs: This style offers a good, comfortable fit in the palm of the hand, and works particularly well in two-finger operations. However, if the operator may be wearing gloves, make sure the configuration of the particular mushroom knob will accommodate. This design, like the ball knob, may not be suitable for wet or greasy situations. Pictured is the EN 597.1 metric size technopolymer plastic revolving mushroom knob with threaded stud. EN 597
MVP Tapered knobs: The length of these knobs makes them great for side-to-side or up/down movements. They are particularly good for applications that operate by grasping and rotating from a 90 degree angle. But bear in mind that unless fluted or knurled, they can be slippery in wet or greasy environments. You see here the MVP metric size PVC cylindrical handle, which has a push-fit mounting.
Push-pull knobs:These simple knobs vary in style but generally speaking are easy to operate and control. Solid push-pull knobs are simple to clean; remember that open-backed styles can collect dirt or other contaminants. If the application will involve lots of use or stress, opt for a type made of metal or with a metal insert. Again, these knobs can get slippery, so you may want to consider a style that is knurled. Shown is the GN 676.1 metric size steel push-pull knob with tapped blind hole, available with plain or knurled rim. GN 676.1
VEG Clamping knobs: This category of knob includes a number of styles--star, scalloped and lobed--designed to work in applications that require turning and clamping. The indentations in the rim allow for the achievement of mild to medium torque. These types of knobs are also easy to grip and work well in slippery environments. (Bear in mind that for higher torque requirements, a pronged knob or even a handwheel may be preferable.) Pictured is our GN 6336.10 metric size, nylon plastic hand knob with stainless steel threaded stud, with brass or nylon tip.
Prong knobs: Speaking of, here's a design of knob perfect for higher torque requirements. The protrusions on a prong knob are longer (certain star knobs may also fall in this category), increasing the leverage of the operator's fingers. In light torque situations, one finger may be all that is required to turn a prong knob. The downside of this style is the increased surface area, which makes it harder to clean. And if steady, unbroken turning is required, go with a crank or handwheel. Shown is our CKS inch size aluminum extruded four-prong clamping knob, which comes in tapped, tapped through hole, blind bore and blank types. CKS
EN 634 Wing nuts/screws: These knobs are basically a two-pronged prong knob. Consequently, they function in applications where the operator needs to apply torque using thumb and finger only. Metal or metal-insert wing nuts can achieve quite good clamping force. Here you see the EN 634 inch size, technopolymer plastic Ergostyle® wing screw with tapped brass insert.
Knurled rim knobs: This group encompasses a variety of knob styles (ball, push-pull, clamping, mushroom, tapered) but utilizes ridges or knurls at the rim to improve grip. The knurled rim is the answer for greasy or wet environments where slipperiness must be reduced. But knurling sacrifices easy of cleaning, so may be a problem in clean room and food applications, etc. Pictured is the KRSK inch size, stainless steel knurled rim knob, available with tapped or blind bore. KRSK
VU Control knobs: Control knobs are used for the fine control or adjustment of devices, and may be referred to as instrument knobs, electronic knobs, or electrical knobs. They come in a variety of styles, and may include a revolving handle and/or scale markings for measurement. Pictured is the VU phenolic plastic five-lobed control knob with steel hub, which can be used interchangeably for inch or metric.
Pointer knobs: This specific type of control knob is designed in a pointer shape. The design makes it easy to operate with thumb and finger. It works well when the application involves a few options (off/on, open/closed, etc.), or when it employs some sort of scale markings. You see here the MRI phenolic plastic pointer knob, blind bore type with set screw, which can be used interchangeably for inch or metric. MRI

We offer a vast array of knobs to meet every application requirement. To explore the selection, visit our Revolving and Operating Handles section, our Clamping Knobs section, and our Control Knobs section. Meanwhile, J.W. Winco offers the following special modifications:

    - plain or tapped bores
    - square broached holes
    - tapped holes
    - cross holes
    - set screw holes
    - threaded studs
    - stud configurations
    - hub lengths

    - keyways
    - colors

    - graduations and markings
    - kitting, packaging and labeling
    - assembly

And if you have special issues or concerns, by all means contact our Technical Sales Associates (800-877-8351) and we'll be glad to assist.

 

 

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