Grease Fittings at G.L. Huyett

G.L. Huyett is a master distributor offering a wide variety of grease fittings for your fastening needs. Contact us to speak with our friendly, experienced Sales team to find just the right part for you!

Click a link below to shop by category or check out our "Additional Resources" to learn more.

Grease Fittings

Grease fittings, also known as zerk fittings or grease nipples, serve as lubrication points on bearing housings or other mechanical components. Their design provides a secure connection to a grease gun coupler for delivering precise amounts of grease into bearings and other moving systems.

• Offered in steel, Monel®, and stainless steel materials
• Available in bright dip, passivated, zinc clear, and zinc yellow finishes
• A wide range of grease fittings is available to fit a variety of applications.

Button Head Fittings

Button head grease fittings are a heavier duty fitting identified by their flat, low profile appearance. They are able to handle large grease volume due to their high flow rate and sturdy construction. They are commonly used on conveyors, mining equipment, agricultural equipment, and other rugged applications.

• Flat head design minimizes damage from debris
• Quickly connect and remove grease gun for faster servicing
• Easily greased using a button head coupler
• Available in Metric and Imperial sizes

Ball Type Fittings

Ball type fittings are a reliable solution for any application requiring frequent lubrication. They are identified by their smooth, dome shaped nipple and feature a ball check valve taht reduces back flow when grease is applied.

• Serviced using push type grease fitting couplers
• Offered in Metric sizes
• Hex wrench holds allow for simple installation

Pin Type Fittings

Pin type grease fittings use a cross pin to create a positive lock with a special coupler to provide a leak‑proof connection during servicing. Pin type grease fittings were one of the first styles of grease zerks manufactured and are still being used for vehicle restorations and other applications where positive lock coupling is desired.

• Available in zinc clear, zinc yellow, or traditional steel
• Original equipment replacement for early model vehicles
• Simple servicing when used with pin type couplers

Leakproof Grease Fittings

Leak‑proof fittings prevent lubricant leakage using a plastic, rubber, or brass seated steel ball check. Intended for light oils and hydraulic fluids, leak‑proof grease zerks are often used in the textile and food processing industries where prevent lubricant leakage is critical.

• Available in zinc clear, zinc yellow, or traditional steel finish
• Designed to provide leak‑proof seals up to 10,000 psi
• Drive in options available for efficient production assembly

Flush Fittings

Flush grease fittings are a low profile zerk fitting that excells in applications where clearance tolerances between moving parts is minimal. Their low profile design makes them a great fit for shafts, pulleys, and other rotating assemblies. Since flush type grease zerks don't protrude from their mating surface like standard grease fittings, they are less susceptible to damage.

• Available in zinc clear trivalent, cadmium green, and zinc yellow
• Easily serviced using a flush type coupler
• Large diameter flush type fittings are ideally suited for high volume applications

Flow Stop Fittings

Flow stop fittings® control how much grease is able to flow out of the fitting. It is designed to positively shut off at a specific pressure, thus preventing over greasing and damage to seals. The fitting reopens once pressure drops within 2 psi of the stated minimum pressure.

• Equipped with a check ball to reduce risk of contamination
• Available in corrosion resistant zinc clear or zinc yellow finish
• Smart technology prevents over lubrication of equipment

Safety Vent Fittings

Safety vent fittings, or safety grease fittings, are externally similar to standard grease zerks. However, they boast the additional feature of a milled vertical slot in the threads. This slot serves as an air vent while grease is being applied to a mechanical component. The slot also serves as a visual aid as grease will flow out when enough has been applied.

• Provides a visual indicator when enough lubricant is in an assembly
• Reduces risk of damage from excessive pressure build up
• Stainless steel variations are ideal for marine environments or other corrosive applications

Hydraulic Shut Off Fittings

Hydraulic shut off fittings control the grease that flows out of a fitting. It closes at a specific pressure to prevent over greasing and damage to seals. The fitting reopens once pressure drops within 2 psi of the stated minimum pressure.

• Equipped with a check ball to reduce risk of contamination
• Available in corrosion resistant zinc clear finish
• Serviced using a standard coupler

Drive Type Fittings

Drive type grease fittings, also called push in grease fittings, are ideal for low or medium pressure applications. They feature serrated or smooth shanks for installation in drilled, untapped holes. Using drive type grease zerks can eliminate tapping costs associated with threaded applications.

• Ideal for automated, high volume, assembly line productions systems
• Low volume installation made simple using a grease fitting driver tool
• Available in a variety of angles allowing easier access in hard to reach areas

Thread Forming Fittings

Thread forming grease fittings, or spin drive fittings, feature hardened threads for installation into thin, unthreaded holes. Using thread forming fittings eliminates costs associated with tapping methods and forms stronger, cold worked threads in the process.

• Ideal for high volume, assembly line applications
• Various available angles allow easier access in hard to reach areas
• Offered in clear and yellow zinc as well as passivated and bright dip finishes

Breather Fittings

Breather fittings, or breather valves, are designed to maintain proper atmospheric pressure in transmissions, differentials, gear boxes, speed reducers, and more. The simple design of these zerk fittings provides a moisture barrier while maintaining air flow efficiency and reducing debris entry. Some grease zerk breather fittings are additionally equipped with a felt filter for increased protection against contamination.

• Offered in corrosion resistant zinc clear and zinc yellow finishes
• Allows unrestricted bi-directional airflow
• Prevents gasket distortion between mating parts by maintaining proper pressure in sealed assemblies

Relief Vent Fittings

Pressure relief valves, or relief vent fittings, release excessive pressure that builds during mechanical operation in bearing housings or gear boxes. As pressure increases, the internal valve opens allowing pressurized air to escape. Once pressure decreases below a minimum threshold, the valve returns to a closed state.

• Upper pressure range indicated on the top or side of the fitting
• For best performance, install above fluid level
• Side vent valves available through special order

Vent Fittings

Vent fittings, also referred to as air vent fittings, control pressure build up in a lubricated assembly by opening and closing in a pre‑determined range. As pressure increases, the spring loaded valve opens, allowing pressure build up to escape. As pressure returns to the desired threshold, the valve closes.

• Equipped with a felt liner for added protection against contamination
• Performs best when placed higher than normal lubrication level
• Available in zinc clear and zinc yellow plating for added corrosion resistance

Oilers

Oilers are a lubrication fitting intended for oil fill points on machinery. They are equiped with a spring hinged lid similar to oil hole covers for self‑closing to keep contaminates out of oil fill holes. They are machined from bar stock with hex wrench holds, making them durable and simple to install.

• Available in Imperial sizes
• Finished in a corrosion resistant zinc clear coating
• Hole covers with 90° elbows provide easy access for lubrication

Oil Reservoirs

Oil reservoirs feature clear plastic bowls brazed to an externally threaded fitting. With increased holding capacity, they are the ideal choice for use as a central dispenser for lubrication systems. Oil reservoirs are available in varying capacities from 1 oz to 128 oz.

• Adjustable flow reservoirs allow oil to be dispensed from a drip to a steady flow
• The clear reservoir makes checking levels fast and simple
• Zinc plated hardware provides enhanced corrosion resistance

Drive Oilers

Drive oilers are often used as oil fill ports for machinery and feature a tapered shank to create a snug, press fit in drilled hole applications. Similar to oil hole covers, they feature a self‑closing lid that prevents contaminates from entering an oil hole.

• Trivalent zinc plated steel for added corrosion resistance
• Integrated shoulder reduces risk of cracking castings during installation
• Does not require threaded holes for installation

Oil Cups

Oil cups are small reservoirs that hold small amounts of oil for machinery and allow for slow, constant lubrication of moving parts. Oil cups are simple, yet reliable components that can be used in a variety of applications.

• Equipped with a self‑closing lid to reduce contamination
• Machined hex holds for simple installation
• Body and shank are brazed together for a secure, leak proof connection

Hole Covers

Oil hole covers, or flip lids, are designed for oil fill points on machinery but do not hold any lubricants like oil cups. They are equipped with a self‑closing, spring hinged lid that minimizes risk of debris entering internal machine components.

• Feature hex holds for simple installation and removal
• Finished in a corrosion resistant zinc clear coating
• Hole covers with 90° elbows provide easy access for lubrication

FREQUENTLY ASKED QUESTIONS

• Where can I buy a zerk grease fitting?
• How do grease fittings work?
• What is the most common standard size grease fitting?
• How much grease should I put on a fitting?
• Can you over‑grease a fitting?
• How to attach a grease gun to a zerk fitting
• How to grease a zerk fitting
• How to remove a grease gun from a zerk fitting
• What size thread is used on a zerk grease fitting?
• How to replace a grease fitting with a grease fitting multi tool

• How to remove a broken grease zerk
• How to remove or free up stuck grease fittings
• How to install a drive type grease fitting
• How to remove a drive type grease fitting
• How to install self-tapping grease fittings
• How to grease a button head fitting
• How to extend grease fittings for hard to reach places
• What if my grease fitting won't take grease?
• How to clean a grease fitting

What is a zerk grease fitting?

A zerk grease fitting (also known as a grease fitting or grease nipple) patented by Oscar Zerk in 1929 is used in mechanical systems to feed lubricants like lubricating grease into a bearing using a grease gun. It was introduced as an improved method of lubricating moving parts. Zerk fittings are permanently installed on bearing housings or mechanical components to serve as a lubrication point to feed precise amounts of grease into bearings and other moving systems. Zerk fittings come in variety of types, such as Drive In, Rivet, and Thread Forming. They can be manufactured using brass, stainless steel, and Monel® materials.

Where can I buy a zerk grease fitting?

G.L. Huyett offers its own complete private line of Heritage Industrial® grease fittings and accessories at the lowest distributor price! We are also a Master Distributor for Alemite®, Alemite Aerospace®, and Lincoln® brands. In addition, we offer a complete line of metric and international grease fittings. If you don’t find what you are looking for, call us today to speak with our friendly, experienced sales team.

How do grease fittings work?

Grease zerk fittings work by acting as a one‑way check valve that allows grease to pass through one way, but not the other. Inside the fitting is a ball check suspended by a spring. As grease is pushed into the fitting, pressure is created against the ball check that compresses the spring allowing grease to pass completely through the fitting. When grease flow stops, the spring pushes the ball check back to its original position, closing the fitting and preventing grease to escape.

What is the most common standard size grease fitting?

The most common standard grease fitting size is 1/4"‑28 SAE‑LT and is often used in automotive applications. They can also be found in agricultural environments as well as other various standard duty applications. For heavy duty applications, larger 1/8"‑27 PTF zerk fittings can be found.

How much grease should I put on a fitting?

The amount of grease put in a fitting depends on the size of the part to which it is attached. As a general rule of thumb, apply grease until you begin to feel resistance while pumping. Do not apply grease until it seeps out of bearing seals or other components.

Can you over‑grease a fitting?

Yes. Only apply grease until you begin to feel resistance while pumping. Do not apply grease until completely full or seeping out of the fitting or other components. Changes in temperature or pressure can cause the grease to expand causing further leaks, which can cause dirt, gravel, or other debris to collect on the exposed grease and work into the moving part, shortening its lifespan.

How to grease a zerk fitting:

While grease fittings themselves do not require grease, the part they are attached to does. To grease the part, attach a grease gun to the end of the zerk fitting and pump until you feel resistance. It is a good idea to refer to your equipment’s service manual for recommended maintenance practices when possible.

What are the different types of grease guns?

There are many different types and designs of grease guns, and we offer lever, pistol, cordless, and pneumatic grease guns. We have a gun for practically any application. G.L. Huyett offers the following on our site.

Lever Gun

Our standard lever gun is not only economical, but also provides the most volume per stroke as compared to other manual guns. A full range of interchangeable / customized features are available to suit your individual needs. ** Lever guns require two hands to operate. **

Pistol-Grip Gun

Pistol-grip grease guns are good for use in close-clearance areas. Using just one hand, grease is pumped via a simple squeeze. Pistol-grip guns typically dispense less grease per stroke than a standard two-handed lever gun.

Cordless Gun

Cordless grease guns use rechargeable Lithium-ion batteries for complete portability and ease of use. Huyett grease guns come equipped with a carrying case and two batteries for extended use. ** Cordless grease guns are trigger operated, portable, and convenient. **

How to attach a grease gun to a zerk fitting

1. First, ensure both the zerk fitting and the grease gun coupler are clean and free of debris and other contaminates. This will help ensure a secure connection between the fitting and the coupler.
2. Next inspect the fitting to ensure there is no damage. If the fitting is damaged, you may want to consider replacing the fitting before continuing.
3. Once everything is clean and inspected, set coupler at an angle to fitting and while firmly pressing down, roll the coupler onto the fitting. You should feel the coupler clamp down on the fitting and click into position.