A guide to knobs: types, materials and applications

Small plastic knobs. Machine knobs and handles. Plastic threaded knobs. Black metal knobs. Where do you even start when knobs come in different shapes, sizes and materials, for a variety of applications?

Our guide will help you decide which knob is suitable for your application. We've listed solutions by material to help you make the right choice.

What are the type of knobs?
Knobs material: how do they compare?
Common knob applications

What are the types of knobs?

Fluted knobs	The grooves, or fluting, on the side result in a firm grip when turning the knob
Lobe knobs	Ideal for medium- to high-torque requirements Provides exacting control A knob with three to eight lobes is a clamping knob, sometimes called clamp knobs, which provide positive clamping action Four lobes are sometimes called hand knobs
T Handle knobs	Sometimes called a wingnut knob A type of lobe knob with two lobes Easy to grip Ideal for applications requiring high torque
Push Pull knobs	Enlarged head allows for finger clearance and good grip
Grip knobs	Suitable for confined spaces Available with knurled texture for no-slip grip
Ball knobs	Round, as the name implies Usually used as an operational handle Ideal for applications that require up-down and side-to-side movement
Knurled knobs	Small pattern on side provides a non-slip grip Knurled rim helps keep fingers from slipping Ideal for applications where wet or damp surfaces are involved
Wing knobs	Suitable for confined spaces Designed for frequent tightening and loosening Easy to grip Available with quarter-turn latches, which makes an ideal panel latch for a rack mount cabinet, for example
Thumb screw knobs	For use instead of a nut or bolt or press fit onto screws Creates a small knob for clamping or securing Ideal for environments with limited space
Tapered knobs	Acts as a handle grip at the end of an operating lever, gear stick or handwheels Comfortable and secure grip

 

Knobs material: how do they compare?

The environment your application is going in will affect the material you choose. And it’s not just the knob material, but the knob’s insert material that you need to consider. For example, inserts for female threaded knobs are molded into the knob material, such as plastic, at the point of manufacture. It’s the insert that gives your knob the desired strength, which in turn enables the maximum torque.

Additives can be applied to materials at the point of processing to enhance desired characteristics but knowing the material’s original state helps you make an informed decision. With that in mind, let’s start with common knob materials and examples of knobs from our range. Plastic knobs make up the majority of your choices. 

Nylon

Pros: One of the most popular materials across all industries, nylon offers high-impact resistance. It also gives you excellent resistance to most oils, fuels and greases and has good electrical insulating properties. Plastic hand knobs and plastic threaded knobs are often nylon. Nylon is also used as a material for knob inserts.

Cons: Tends to absorb moisture from surroundings, which can have a negative impact on dimensional stability (yet impact resistance increases). While providing good chemical resistance, nylon can be attacked by strong acids, alcohols and alkalis.

Examples of nylon knobs:

• Fluted grip knobs
• Tapered knobs
• Wing knobs
• Thumb screw knob
• T Handle knobs
• Lobe knobs, male – also known as hand knobs with threaded stud

Phenolic

Pros: Cost-effective phenolic is lightweight and resistant to high impact, heat and wear, and also oils, fuels and greases. It provides excellent corrosion, thermal and electrical resistance.

Cons: It’s a thermoset, which despite its many advantages, does have drawbacks, depending on the intended application. Thermosets are hard and rigid, which also means the material could potentially fail in extremely high-vibration applications. In the case of knobs, however, other material are at work. Take for example, knobs with threaded stud. If it’s made of steel, you can offset this problem.

Examples of phenolic knobs:

• Ball knobs

Thermoplastic elastomer (TPE)

Pros: Flexible TPE is often used as an overlay material to provide a soft, comfortable feel for the end user. An excellent base material in these instances is glass-filled polypropylene, which provides stability and strength. These knobs offer high-impact strength, excellent resistance to ozone and weathering, and good tear and abrasion resistance.

Cons: TPEs cost more than other plastics and are vulnerable to heat aging.

Examples of knobs with TPE:

• Lobe knobs, female threaded

Polypropylene (PP)

Pros: PP is semi-rigid. It resists most chemicals and has good heat and fatigue resistance. As a knob, it’s best for light-duty securing and clamping applications. When used as a base material and filled with glass, it becomes extremely strong.

Cons: PP on its own has poor UV resistance and oxidative degradation is accelerated by contact with copper.

Examples of PP knobs:

• Lobe knobs, female

Low Density Polyethylene (LDPE)

Pros: This low-cost material is semi-rigid, very tough and can be formulated to be weather resistant. It provides good resistance to some chemicals and low water absorption. An LDPE knob also has an attractive, ergonomic finish.

Cons: Without additives, LDPE does a poor job resisting the elements and is not resistant to stress.

Example of an LDPE knob:

• Ball knob

Aluminum

Pros: Aluminum is lightweight compared to other metals, which is why it’s popular with construction and automotive industries. It can be made to almost any strength, and in cold weather, it becomes stronger. It provides very good corrosion resistance and thermal and electrical conductivity. Also used as a material for knob inserts.

Cons: Although its corrosion resistance is highly rated, it’s not as good as stainless steel.

Example of a knob with aluminum insert:

• T handle knob

Stainless Steel

Pros: Stainless steel is excellent for corrosion resistance, standing up to wet environments. Stainless steel  also retains its strength in high temperatures. Stainless steel’s hygienic and non-porous, making it ideal in food and medical applications. Stainless steel also provides an aesthetic appearance, and as a metal, can be recycled. Stainless steel and steel are both used a material for knob inserts.

Cons: If electrical conductivity is important, look elsewhere. Stainless steel performs relatively low in that area. Stainless steel also tends to cost more than plastics, but depending on your application, this could be worth it.

Example of a knob with steel insert:

• Tapered knob

Brass

Pros: Brass is a copper-zinc alloy and often used for as a material for knob inserts due to its integral core strength. It’s wear resistant and frequently used when low friction is required, which includes locks, bearings, and gears. Brass is also used to make screws, nuts and bolts. Brass also has excellent thermal conductivity, which is why it’s often used with as heat exchangers, such as radiators. You’ll also find brass in electrical and other plumbing applications.

Cons: Metals oxidize when exposed to the air, and brass is no different. Still, its corrosion resistance is good. It’s worth noting that the higher the zinc content, the higher the corrosion resistance. Brass is also soft compared to other metals, but that has its benefits, namely, it’s easy to machine. Finally, brass can cost more than other materials.

Example of a knob with a brass insert:

• Push pull knobs

Knob material properties

To learn more about the material that interests you, click on that material. Note, some materials resist some chemicals better than others. It’s best to check the compatibility of your desired material with specific chemicals. The materials below are being used for push pull knobs, tapered knobs, ball knobs, lobe knobs, wing knobs, plastic knobs, and many more. 

✔ = poor ✔✔ = good ✔✔✔ = excellent

Material	Impact resistance	Corrosion resistance	Chemical resistance	Electrical insulator	Electrical conductor
Nylon	✔✔✔	✔✔	✔✔✔	✔✔	✔
Phenolic	✔✔✔	✔✔✔	✔✔✔	✔✔✔	✔
TPE	✔✔✔	✔✔✔	✔✔✔	✔✔✔	✔
PP	✔✔	✔✔✔	✔✔✔	✔✔✔	✔
LDPE	✔✔	✔✔	✔✔	✔✔✔	✔
Aluminum	✔✔✔	✔✔✔	✔✔	✔	✔✔✔
Stainless Steel	✔✔✔	✔✔✔	✔✔✔	✔	✔✔
Brass	✔✔	✔✔	✔✔	✔✔	✔✔

Common knob applications

Which knobs are popular according to industries? This table will give you an overview:

Knob	Appliances	Machinery/ machine tools	Commercial vehicles	Hydraulics	Electronics	Electrical & Data cabinets	Furniture	Medical devices
Ball knobs	✔	✔		✔	✔
Control knobs					✔	✔		✔
Fluted knobs		✔			✔
Knurled knobs				✔	✔
Lobe knobs			✔					✔
T Handle knobs	✔
Push pull knobs	✔				✔		✔
Mushroom knobs		✔
Wing knobs	✔					✔		✔
Thumb screw knobs	✔						✔
Grip knobs							✔
Tapered knobs		✔	✔		✔

Download free CADs and try before you buy

Free CADs are available for most solutions, which you can download. You can also request free samples to make sure you’ve chosen exactly what you need. If you’re not quite sure which solution will work best for your application, our experts are always happy to advise you.

Whatever your requirements, you can depend on fast despatch. Request your free samples or download free CADs now.

Questions?

Email us at sales@essentracomponents.com or speak to one of our experts for further information on the ideal solution for your application 800-847-0486.