grease fitting

A-Z guide to grease fitting types, sizes and thread identification

Most of the time, finding the ideal grease fittings for your use is easier said than done. The reason is that they come in many different types, sizes, and distinctive functions.

Although grease fittings are fundamental to proper machine lubrication, harm and damage could ensue if they are misused. Spotting the most suitable grease fitting may seem like a challenging task but take it easy! 

With this article, you will learn how to identify grease fittings and navigate your grease fittings selection properly. So, let’s dive in and find the right parts for you! 

Grease fitting basics

Functions 

A grease fitting, sometimes called a Zerk fitting, grease nipple, or Alemite fitting is a small metal fixture used on mechanical assemblies. It provides lubrication to internal parts without leaks or overspill. Adding lubricants to mechanical systems helps improve their efficiency.

The grease fittings remain closed until the pressure from the grease gun opens them to dispense grease into the system’s moving parts, greatly reducing the possibilities of machinery failure. 

Design

Grease fittings are set in place by a threaded connection. Inside the fitting, a small captive bearing ball is pushed against a retaining spring by the grease gun’s pressure.

The setup operates as a pathway that allows the grease to flow to the bearing. When the pressure releases, the bearing ball returns to the tip. 

The bearing ball blocks dirt and other wastes from entering the bearing. It also acts as a check valve that creates a seal, obstructing the grease from flowing back out of the fitting. 

Grease fittings are attached to a grease gun to administer a pressure-resistant connection. Also, they have a channel behind the opening that runs straight to the area where you need to grease.

Material

Most grease fittings are made of zinc-plated steel, stainless steel, carbon steel, mild steel, or brass. Some variations also have a supplemental coating of chromate to limit corrosion and improve durability.

Grease fitting thread identification

Types of grease fitting threads

There are many types of grease fitting threads available for use. But how can you be certain about the functionality of your grease fitting thread assembly? Let’s learn how to identify common thread types and how to choose the best for your application!

Threads are the ridges that wrap around the cylinder or cone and form a coil. There are six common different types of threads:

+ BSPP (British Standard Pipe Parallel)

+ BSPT (British Standard Pipe Taper)

+ Metric parallel

+ Metric tapered

+ NPT/NPTF (National Pipe Thread/National Pipe Thread Fuel)

+ UN/UNF (United/United Fine)

How to identify grease fitting thread

Keeping track of the six commonly used types of threads is not a simple task. It’s easy to select an incorrect part accidentally, but the following text offers a few ways to get to the correct choice. Here are some ways to identify the threads on your grease fittings:

With a grease fitting gauge

Using a specific tool called grease fitting thread gauge is the easiest method to determine the thread on a grease fitting. 

grease fitting gauge
Grease fitting gauge – the easiest method to determine the thread on a grease fitting

This special tool helps save time and grants a simple way to distinguish one grease fitting thread from another. It includes the standard metric sizes such as the UNF, the American standard, the British standard, and many more. 

Without a grease fitting gauge

Although having a grease fitting thread gauge is convenient, you can still identify the correct grease fitting thread through various ways without needing this tool.

Parallel vs. Tapered 

To determine if the thread is parallel or tapered, focus on its diameter. If the thread’s diameter runs straight from top to bottom, the thread is parallel. But if the thread’s diameter gets narrower towards the bottom, the thread is tapered. 

straight thread vs tapered thread
Straight thread (left) vs. tapered thread (straight)
Parallel ThreadsTapered Threads
BSPPBSPP
Metric parallelMetric parallel
UN/UNFNPT/NPTF

Thread pitch 

 pitch gauge
The optimal way to compare the numerous threads is to use a pitch gauge

The thread pitch is the number of threads per inch. A pitch gauge measures the distance between the individual crests or the pitch of a thread, and it is the optimal way to compare the numerous threads. 

Thread TypePitch Size
BSPP
11, 14, 19, 28
BSPT
11, 14, 19, 28
Metric parallel1.0, 1.5, 2.0
Metric tapered
1.0, 1.5, 2.0
NPT/NPTF11½, 14, 18, 27
UN/UNF
12, 14, 16, 18, 20, 24

Thread diameter

A caliper tool is handy for measuring the thread diameter of your grease fitting. In addition, it is a simple two-part tool that can measure the internal and external diameters of objects.

caliper
Measure the internal and external diameters of grease fittings with a caliper

Use the lower jaw of your caliper to measure the external diameter of your grease fitting. The diameter of your grease fitting would be the point where the 0 (zero) mark of your caliper’s slider is pointed at.

Types and sizes of grease fittings

Learning the different types and sizes of grease fittings is an important step, but it will be a little confusing. In this breakdown, we will introduce you to various grease fittings that provide the world with a quick and functional greasing procedure. Let’s explore some of the grease fitting assortments. 

1/4”- 28 taper thread fittings

¼”-28 taper thread fittings are usually zinc-plated. They are suitable for use in automobiles and other kinds of commercial machinery. Some of its features include a dirt-repellent ball check and a maximum pressure range of 10,000 psi.

taper thread fittings
Alemite #
Lincoln #
SAE
#

Descriptions
Type
Thread
FIG.Overall
Length
(A)

Shank
Length
(S)

Hex
Size
(H)

1637-B1
5210
H-145
1/4"-28 SAE 45 degree
45°
1/4"-28 Taper (SAE-LT)
227/32"
7/32"
3/8"
1641-B
5010H-1001/4"-28 SAE straightStraight
1/4"-28 Taper (SAE-LT)
135/64"
3/16"
5/16"
1652-B
5013
H-100-RLA
1/4"-28 SAE long thread
Straight
1/4"-28 Taper (SAE-LT)
411/16"
23/64"
5/16"
1680-B
5014
H-100-LMA
1/4"-28 SAE medium long
Straight
1/4"-28 Taper (SAE-LT)
431/32"
5/8"
5/16"
1698-B
5017
H-100-LA
1/4"-28 SAE long
Straight
1/4"-28 Taper (SAE-LT)
41-1/8"
25/32"
5/16"
1911-B1
5410
H-190-A
1/4"-28 SAE 90 degree
90°
1/4"-28 Taper (SAE-LT)
33/4"
7/32"
3/8"
3010-B1
700396
H-165-RL
1/4"-28 65° long thread
65°
1/4"-28 Taper (SAE-LT)
213/16"
19/64"
3/8"
3014-B
N/A
H-100-LLA
1/4"-28 straight very longStraight
1/4"-28 Taper (SAE-LT)
41-5/8"
1"5/16"
N/A5311
H-165
1/4"-28 SAE 65 degree
60°
1/4"-28 Taper (SAE-LT)
23/4"
7/32"
3/8"

1/4”- 28 straight thread fittings

¼”-28 straight thread fittings are zinc-plated fittings frequently used in cars and a range of industrial equipment.

straight thread fittings
Alemite #Lincoln #
SAE #


Descriptions
Type
Thread
FIG.Overall
Length
(O)

Shank
Length
(S)

Hex
Size
(H)

333330
N/A
H-100-28-LA
1/4"-28 UNF-2A straight

Straight
1/4"-28 UNF-2A
117/32"
3/16"
17/32"
369609
N/A
H-100-28-C
1/4"-28 UNF-2A straight

Straight
1/4"-28 UNF-2A
17/16"
1/8"
5/16"
1770-B1
N/A
H-145-CU
1/4"-28 UNF-2A 45 degree
45°
1/4"-28 UNF-2A
241/64"
1/8"
3/8"
1792-B
5527
H-100-28
1/4"-28 UNF-2A straight
Straight
1/4"-28 UNF-2A
133/64"
5/32"
9/32"

Metric grease fittings

Metric grease fittings sometimes called metric hydraulic fittings and metric zerks can take the pressure up to 10,000 psi. Their material is often regular and stainless steel. You can find this type of fitting in industrial machinery, rugged automotive, and agricultural applications.

metric grease fittings
Alemite #
Lincoln #
SAE
#

Descriptions
Type 
Thread
FIG.Overall
Length
(O)

Shank
Length
(S)

Hex
Size
(H)

2109
5181
M10-1-AM
10mm x 1mm / straight
Straight
10mm x 1mm115.2mm
5.9mm
11mm
2110
5182
M10-45-AM
10mm x 1mm / 45 degree45°
10mm x 1mm223.5mm
5.5mm
11mm
2111
5183
M10-90-AM

10mm x 1mm / 90 degree

90°
10mm x 1mm319.0mm
5.5mm
11mm
2106
5175
M6-1-AM
6mm x 1mm / straight
Straight
6mm x 1mm
113.5mm
4.6mm
7mm
2107
5176
M6-45-AM
6mm x 1mm / 45 degree45°
6mm x 1mm
222.6mm
5.5mm
9mm
2108
5177
M6-90-AM
6mm x 1mm / 90 degree
90°
6mm x 1mm
318.0mm
5.5mm
9mm
2103
5178
M8-1-AM
8mm x 1mm / straight
Straight
8mm x 1mm
114.7mm
5.6mm
9mm
2104
5179
M8-45-AM
8mm x 1mm / 45 degreeStraight
8mm x 1mm
214.9mm
5.8mm
9mm
2105
5180
M8-90-AM
8mm x 1mm / 90 degree
90°
8mm x 1mm
317.8mm
5.5mm
9mm

Flush type grease fittings

Flush type grease fittings are suited for machines where protruding fittings cannot be equipped, such as pulleys, shafts, and other rotating bearings. Flush fittings are not susceptible to erosion since they don’t protrude from the surface like other fittings.

flush type grease fittings
Alemite #Lincoln #SAE
#
DescriptionsTypeThreadFIG.Overall
length
(O)
Shank
length
(S)
1452N/AAH-18FLMA1/8"-NPTF Slotted ThreadSlotted1/8"-NPTF217/32"N/A
1814N/AAK-516F5/16" Drive, no threadStraightDrive (No Thread)721/64"9/32"
1815N/AAH-18F1/8"-NPTF Slotted ThreadSlotted1/8" NPTF123/64"19/64"
1851700392AH-1428FJ1/4"-28 U.N.F1/4"-28 U.N.F10-32 U.N.F413/32"19/64"
1877700397AK-18FC1/8" Drive, Slotted ThreadStraightDrive (No Thread)611/64"1/8"
1885700502AK-14-FJ-11/4" Drive, Slotted ThreadStraightDrive (No Thread)79/32"15/64"
3036N/AAH-316F3/16"-DriveStraightDrive63/8"5/16"
N/A700502AAH-1032FJ10-32 U.N.F Slotted ThreadStraight10-32 U.N.FN/A11/32"15/64"
Z741-AN/AAH-14F1/4"-NPTF Slotted ThreadSlotted1/4"-NPTF39/16"N/A

Button head grease fittings

Button head grease fittings can be for strenuous applications such as heavy machinery and high-powered equipment. They are appropriate for delivering high amounts of lubrication for smooth and fluid work.

button head grease fittings
Alemite
#

Lincoln
#

SAE
#

Descriptions
Type
Thread
FIG.Overall
Length
(O)

Shank
Length
(S)

Hex
Size
(H)

1823
N/A
H-300-CBG
1/4"-NPTF
Straight (Giant)
1/4"-NPTF
11-9/32"
35/64"
7/8"
1831
N/AH-200-CBG
1/8"-NPTFStraight (Giant)
1/8"-NPTF
11-3/16"
29/64"
7/8"
1820-1
N/AH-500-CBG-SS
1/2"-NPTF (STAINLESS)
Straight (Giant)
1/2"-NPTF
11-1/16"
1/2"
7/8"
1822-A1
N/AH-400-CBG
3/8"-18 NPTF
Straight (Giant)
3/8"-18 NPTF
11-5/16"
9/16"
7/8"
A1184
5700/5701
H-200-CB
1/8"-NPTF
Straight

1/8"-NPTF
13/4"
23/64"
5/8"
A1186
5706
H-300-CB
1/4"-NPTF
Straight

1/4"-NPTF
127/32"
7/16"
5/8"
A1188
5711
H-400-CB
3/8"-NPTF
Straight

3/8"-NPTF
11-1/16"
37/64"
3/4"
A1190
N/A
H-500-CB
1/2"-NPTF
Straight
1/2"-NPTF
11-1/16"
35/64"
7/8"
C-69
N/A
H-200-CBRI
1/8"-NPTF FEMALE
Straight
1/8"-NPTF
131/32"
13/32"
5/8"
M1184
N/A
H-200-CB-MON.
1/8"-PTF (MONEL)
Straight
1/8"-PTF
13/4"
11/32"
5/8"

Hydraulic shut-off grease fittings

Hydraulic shut-off fittings are often suitable for bearing seals in water pumps. These fittings shut off at certain pressure levels, therefore restricting over-greasing and over-pressurization of the bearing seals.

hydraulic shut off grease fittings
Alemite #
SAE #
Descriptions
Type

Thread

FIG.Overall length (O)
Shank length (S)
Hex size (D)
Shut-off
Pressure (psi)
1795-B
H-260-SO2
1/8" PTF / 60° Angle
60°
1/8" PTF
11"
17/64"
5/8"
5-20 lb
1940-B
H-260-SO1
1/8" PTF / 60° Angle
60°
1/8" PTF
11"
17/64"
5/8"
60-110 lb

Special thread grease fittings

Special thread grease fittings are special threads and sizes for specific greasing usage. They are suited for matching corresponding straight threads. Moreover, most of them include a high-pressure ball check and you can customize the special threads to fit almost any use.

special thread grease fittings
Alemite
#

Lincoln
#
SAE
#

Descriptions
TypeThread
FIG.Overall
Length
(O)

Shank
Length
(S)

Hex
Size
(H)

3016
N/A
H-1032
10-32 UNF-2A straight
Straight
10-32 UNF-2A
11/2"
1/8"
1/4"
3018
N/A
H-640
6-40 UNF-2A straight
Straight
6-40 UNF-2A
11/2"
9/64"
1/4"
1631-B
N/A
H-51632
5/16"-32 UNEF-2A straight
Straight
5/16"-32 UNEF-2A
121/32"
7/32"
3/8"
1648-B1
N/A
H-5163265
5/16"-32 UNEF-2A, 65 degree
65°
UNEF-2A
251/64"
7/32"
3/8"
1711-B
5061
H-51624
5/16"-24 UNF-2A straight
Straight
5/16"-24 UNF-2A
121/32"
1/4"
3/8"

Pin type grease fittings

Pin type grease fittings include a cross pin that creates a lock to allow no room for leaks. Pin type grease fittings were one of the first zerks developed and still being used in automobiles today.

pin type grease fittings
Alemite
#

SAE
#

Descriptions
Type
Thread
FIG.Overall
Length
(O)

Shank
Length
(S)

Hex
Size
(H)


A336
H-200-PIN-B
1/8" PTF / str. (brass body / steel pin & ball)
Straight
1/8" PTF
131/32"
17/64"
7/16"
A358
H-290-PIN-B
1/8" PTF / 90 degree (brass)90°
1/8" PTF
21-1/16"
17/64"
1/2"
A359
H-300-PIN-B
1/4" NPTF / straight (brass)Straight
1/4" NPTF
111/32"
17/64"
17/32"
A361
H-390-PIN-N
1/4" NPTF / 90 deg. (steel/ nickle)
90°
1/4" NPTF
21-5/16"
3/5"
9/16"
A684
H-245-PIN-B
1/8" PTF / 45 degree (brass)45°
1/8" PTF
N/A1-1/2"
5/16"
1-9/16"
M336
H-200-PIN-M
1/8" PTF / str. (brass body / brass pin & ball)Straight
1/8" PTF
131/32"
17/64"
7/16"

Leakproof grease fittings

Leakproof grease fittings prevent lubricant leaks and keep external particles from entering the channel. Besides, this type of fitting is suitable for operations where having firm seals is critical, like in the food and textile industries. A dust cap is a recommended accessory. 

leakproof grease fittings
Alemite
#

SAE
#
DescriptionsType
Thread
FIG.Overall
Length
(O)

Shank
Length
(S)

Hex
Size
(H)

1634
H-200-1634
1/8"-PTF
Straight
1/8" NPT
127/32"
23/64"
7/16"
1650
H-200-LP
1/8"-NPT
Straight
1/8" NPT
129/32"
25/64"
7/16"
1692
H-230-LP
1/8"-NPT 30 degree
30°
1/8" NPT
21-7/32"
25/64"
7/16"
1693
H-290-LP
1/8"-NPT 90 degree
90°
1/8" NPT
331/32"
25/64"

7/16"
369533
CONE-LP
7/16" round, no thread
Straight
7/16" Round
155/64"
N/A
7/16"
369619
H-100-LP
1/4"-28 taper threadStraight
1/4"-28 Taper
137/64"
5/16"
7/16"
1634-B
H-200-1634-B
1/8"-PTF, surface ball ck
Straight
1/8" NPT
11"
33/64"
7/16"

1/8” PTF grease fittings

1/8” PTF grease fittings fit in industrial equipment and heavy machinery. They include a zinc coating and a special dust-proof cap.

1/8” PTF grease fittings
Alemite
#

Lincoln
#

SAE
#

Descriptions
Type
Thread
FIG.Overall
Length
(O)

Shank
Length
(S)

Hex
Size
(H)

1649
N/A
H-265-LLA
1/8"-PTF 65° very long
65°
1/8" PTF SAE Special Short
22-3/4"
2-1/4"
3/8"
1958
N/A
H-200-DR
1/8"-PTF str. dustproof
Straight
1/8" PTF SAE Special Extra Short
N/A
1"
5/16"
7/16"
1606-B
N/A
H-290-LMA
1/8"-PTF 90 medium long90°
1/8" PTF SAE Special Short
31-1/4"
1-1/4"
7/16"
1607-B
5003
H-200-LM
1/8"-PTF medium long
Straight
1/8" PTF SAE Special Short
41-1/4"
25/32"
7/16"
1610-BL
5000
H-200
1/8"-PTF straight
Straight
1/8" PTF SAE Special Extra Short
111/16"
19/64"
7/16"
1611-B
6004
H-230
1/8"-PTF 30 degree
30°
1/8" PTF SAE Special Short
215/16"
19/64"
7/16"
1612-B
5300
H-265-A
1/8"-PTF 65 degree
65°
1/8" PTF SAE Special Short
227/32"
19/64"
7/16"
1613-B
5400
H-290
1/8"-PTF 90 degree
90°
1/8" PTF SAE Special Short
353/64"
19/64"
7/16"
1618-B
5505
H-200-RI
1/8"- NPTF internal threadStraight
1/8" NPT Female
N/A
1"
5/16"
1/2"
1620-B
N/A
H-245-RI
1/8"-NPTF 45° female thrd
45°
1/8" PTF SAE Special Short
N/A1-1/8"
13/32"
7/16"
1623-B
N/A
H-265-LM
1/8"-PTF 65° med. long
65°
1/8" PTF SAE Special Short
21-7/32"
9/16"
7/16"
1638-B
5200
H-230-LMA
1/8"-PTF 30° med. long30°
1/8" PTF SAE Special Short
22"
1-1/4"
7/16"
1644-B
N/A
H-200-C
1/8"-PTF straight shortStraight
1/8" PTF SAE Special Extra Short
19/16"
15/64"
7/16"
1669-B
5007
H-200-LA
1/8"-PTF long
Straight
1/8" PTF SAE Special Short
41-3/4"
1-15/64"
7/16"
1684-B
5009
H-200-LLA
1/8"-PTF very long
Straight
1/8" PTF SAE Special Short
42-5/8"
2-1/32"
7/16"
1688-B
5200
H-245
1/8"-PTF 45 degree
45°
1/8" PTF SAE Special Short
227/32"
19/64"
7/16"

1/4″ PTF grease fittings

¼” PTF grease fittings are extensively used in hefty machinery with bigger bearings with heavy lubricant supplication and for cold weather operations. 

1/4-PTF-grease-fittings
Alemite
#

Lincoln
#

SAE
#

Description
Type
Thread
FIG.Overall
length
(O)

Shank
length
(S)

Hex
size
(H)

1629-C
N/A
H-390
1/4"-PTF 90 DEGREE
90°
1/4"-PTF
315/16"
3/8"
9/16"
1629-B
5350
H-365
1/4"-PTF 65 DEGREE
65°
1/4"-PTF
21-1/16"
3/8"
9/16"
1627-B
5050
H-300
1/4"-PTF
Straight
1/4"-PTF
17/8"
27/64"
9/16"

Pressure relief grease fittings

Pressure relief fittings function as relief vents releasing pressure building up in bearing housings or gearboxes. An internal valve opens and releases pressurized air.

pressure relief fittings
Alemite
#

Lincoln
#

SAE
#

Descriptions
Type
Thread
FIG.Overall
Length
(O)

Shank
Length
(S)
Hex
Size
(H)

47100
N/A
H-200-47100
1/8"-PTF.
Straight
1/8" PTF SAE Spl Short
11/2"
19/64"
7/16"
47200

N/A
H-200-47200
1/8"-PTF.
Straight
1/8" PTF SAE Spl Short
11/2"
19/64"
7/16"
47640
N/A
H-200-47640
1/8"-PTF.
Straight
1/8" PTF SAE Spl Short
11/2"
19/64"
7/16"
50500
N/A
H-200-50500
1/8"-PTF.
Straight1/8" PTF SAE Spl Short
11/2"
19/64"
7/16"
317400
N/A
H-200-317400
1/8"-PTF.
Straight

1/8" PTF SAE Spl Short
11/2"
19/64"
7/16"
321839
N/A
K-38-321839
3/8" DRIVE.
Straight1/8" PTF SAE Spl Short
21/2"
N/A
N/A
323060
N/A
H-200-323060
1/8"-PTF.
Straight1/8" PTF SAE Spl Short
11/2"
19/64"
7/16"
338382
N/A
H-200-338382
1/8"-PTF. LEAKPROOF
Straight1/8" PTF SAE Spl Short
39/16"
11/32"
7/16"
N/A
5677
H-200-5677
1/8"-PTF.
Straight1/8" PTF SAE Spl Short
11/2"
19/64"
7/16"
N/A
5678
H-200-5678J
1/8"-PTF.
Straight1/8" PTF SAE Spl Short
112.7
7.1
7/16"

Thread forming grease fittings

Thread forming fittings, also called spin drive fittings, have hardened threads for insertion into holes with no threads. Besides reducing costs, inserting thread forming fittings into unthreaded holes provide a stronger grip. Thread forming fittings are great for high-pressure oil applicators. You can use them for industrial machinery and heavy equipment.

thread forming grease fittings
Alemite
#
Lincoln
#

SAE
#

Descriptions
Type
Thread
FIG.Overall
Length
(A)

Shank
Length
(B)

Hex
Size
(D)

3038-B
205010
H-100-GM
1/4"-28 straight
Straight
1/4"-28 Spl. Taper
19/16"
13/64"
5/16"
369582
N/A
H-100-C-GM
1/4"-28 straight short
Straight
1/4"-28 Spl. Taper
10.51
0.12
9/32"
369584
N/A
H-100-LMA-GM
1/4"-28, straight med. long
Straight
1/4"-28 Spl. Taper
10.97
0.215/16"
328435
700337

H-100-GMPL
1/4"-28 plugStraight
1/4"-28 Spl. Taper
15/16"
3/16"
9/32"
3053-B
205210
H-145-GM
1/4"-28 45 degree
45°
1/4"-28 Spl. Taper
213/16"
3/16"
3/8"
3054-B
205410
H-190-GM
1/4"-28 90 degree
90°
1/4"-28 Spl. Taper
323/32"
13/64"

3/8"
1720-B
205000
H-200-GM
1/8" PTF straight
Straight
1/4"-28 Spl. Taper
15/8"
1/4"

7/16"
369579
N/A
H-200-LMA-GM
1/8" PTF straight med. long
Straight
1/4"-28 Spl. Taper
10.68
0.21

7/16"
1724-B
5300
H-245-GM
1/8" PTF 45 degree
45°
1/4"-28 Spl. Taper
227/32"
13/64"
7/16"
1722-B
N/A
H-265-GM
1/8" PTF 65 degree
65°
1/4"-28 Spl. Taper
23/4"
13/64"
7/16"
1723-B
205400
H-290-GM
1/8" PTF 90 degree
90°
1/4"-28 Spl. Taper
33/4"
13/64"
7/16"

Drive type grease fittings

Drive type grease fittings, also referred to as push-in grease fittings, are perfect for low or moderate pressure operations. They have serrated shanks for a strong grip. 

drive type grease fittings
Alemite
#

Lincoln
#

SAE
#

Descriptions
Type
Thread
FIG.Overall
Length
(O)

Shank
Length
(B)

Hex
Size
(H)

1633
5026
K-316-SBA
3/16"- drive, no ball
Straight
3/16" Drive
15/8"
1/4"
5/16"
1666
5036
K-38-SBA
3/8"- drive, no ball
Straight
3/8" Drive
137/64"
7/32"
7/16"
1699
5030
K-516-SBA
5/16"- drive, no ball

Straight
5/16" Drive
15/8"
7/32"
3/8"
1736
N/A
K-18-SBA
1/8"- drive, no ball check

Straight
1/8" Drive19/16"
1/4"
5/16"
1744
5318
K-14-65-N
1/4"- drive 65 degree
Straight
1/4" Drive
349/64"
9/32"
1/4"
1952
700313
K-14-CCSBA
1/4"- EXT. short, no ball

Straight
1/4" Drive
115/32"1/8"
11/32"
3005
700375
K-316-MSBA
3/16"- med. short, no ball
Straight
3/16" Drive
1.468"
.172"
5/16"
3006
N/A
K-316-CSBA
3/16"- drive short, no ball
Straight
3/16" Drive
1.484"
.219"
9/32"
3009
N/A
K-316-CCSBA
3/16"- extra short, no ball
Straight
3/16" Drive
1.390"

.105"
5/16"
3019
N/A
K-18-CSBA
1/8"- drive short, no ballStraight
1/8" Drive
115/32"

5/32"
5/16"
321381
5044
K-14-SBA
1/4"- drive, no ball
Straight
1/4" Drive
135/64"

1/4"
11/32"
1608-B
5031
K-516-N
5/16"- drive
Straight
5/16" Drive
19/16''
17/64"
3/8"
1630-B1
N/A
K-516-65-N
5/16"- drive 65 degree
65°
5/16" Drive
323/32"
7/32"
3/8"
1646-B1
5385
K-316-65-N
3/16"- drive 65 degree
60°
3/16" Drive
323/32"
7/32"
3/8"
1728-B
5033
K-316-A
3/16"- drive
Straight
3/16" Drive
133/64"
1/4"
5/16"
1743-B
5029
K-14A
1/4"- drive
Straight
1/4" Drive
135/64"
1/4"
5/16"
1992-B1

N/A
K-316-45-N
3/16"- drive 45 degree
45°
3/16" Drive
253/64"
7/32"
3/16"

Monel grease fittings

Monel grease fittings are excellent at repelling wear and corrosion, especially in industrial settings. Monel fittings’ materials are from nickel or copper. For easy recognition, they feature a single notch on the hex. Because of its corrosion resistance, monel grease fittings are great for caustic environments. Moreover, some good examples of these environments are chemical factories or seaside ports.

monel grease fittings
Alemite
#

SAE
#

Descriptions
Type
Thread
FIG.Overall
Length
(O)


Shank
Length
(S)

Hex
Size
(H)

1921-B
H-230-MONEL
1/8"-PTF 30 degree

30°
1/8" PTF
21-1/4"
11/32"
7/16"
1922-B
H-267-MONEL
1/8"-PTF 67 1/2 degree
67.5°
1/8" PTF
261/64"
11/32"
7/16"
1966-B
H-100-MONEL
1/4"-28 SAE straightStraight
1/4"-28 Taper
117/32"
3/16"
5/16"
1923-B
H-290-MONEL
1/8"-PTF 90 degree

90°
1/8" PTF
37/8"
11/32"
7/16"
1961-B
H-200-MONEL
1/8"-PTF straight
Straight
1/8" PTF
13/4"
5/16"
7/16"
1962-B
H-200-C-MONEL
1/8"-PTF str. short
Straight
1/8" PTF
15/8"
9/32"
7/16"
1968-B
H-145-MONEL
1/4"-28 SAE 45°
45°
1/4"-28 Taper
213/16"
13/64"
5/8"
1969-B
H-190-MONEL
1/4"-28 SAE 90 degree
90°
1/4"-28 Taper
33/4"
13/64"
3/8"

Air vent grease fittings

Air vent grease fittings allow air to enter and exit while preventing dirt and other particles from infiltrating. You can use air vents on mechanical devices such as differentials, transmissions, and gearboxes. 

air vent grease fittings
Alemite
#

Lincoln
#

SAE
#

Descriptions
Type
ThreadFIG.Overall
Length
(O)

Shank
Length
(S)

Opening
Pressure

300805
N/A
H-200-300805
1/8" PTF VENT
Straight
1/8" PTF SAE Spl Short
11
0.19
         Felt Filter
301370
5698
H-200-VENT
1/8" PTF VENT
Straight
1/8" PTF SAE Spl Short
10.78
0.28
             N/A
304810
N/A
H-200-304810
1/8" PTF VENT
Straight
1/8" PTF SAE Spl Short
11
0.19
         1-3" Water
324970
N/A
K-324970
DRIVE VENT
Straight
Drive
11
0.8
         6-12" Water
327240
N/A
H-200-327240
1/8" PTF VENT
Straight
1/8" PTF SAE Spl Short
11
0.19
         1 to 1-1/2 psi   
330766
N/A
H-200-330766
1/8" PTF VENT
Straight
1/8" PTF SAE Spl Short
11
0.19
         2-1/2 to 4 psi
131000-T
N/A
H-200-131000-T
1/8" PTF VENT
Straight
1/8" PTF SAE Spl Short
11
0.19
         12" Water Max.   

Double head grease fittings

Double head fittings provide another head for doubling the lubricant supply. They include a ball check to keep out debris. Its two heads are great when you need to apply grease at two times the speed. It can also be used when two alternating or simultaneous greasing is necessary.

double head grease fittings
Alemite
#

SAE
#

Descriptions
Type
Thread
FIG.Overall
Length
(O)

Shank
Length
(S)

Hex
Size
(H)

369574
H-270-DH
1/8" PTF / 70 DEGREE
70°
1/8" PTF
27/32"
19/64"
1/2"

Stainless steel grease fittings

Stainless steel fittings are made from stainless steel, which is resilient to weathering and corrosion. Besides, stainless steel fittings can tolerate extreme temperatures. They feature two notches for easy recognition. The materials of stainless-steel fittings make them great for high corrosion environments such as seaside or chemical plants. It is also easier to clean thanks to its stainless body.

stainless steel grease fittings
Alemite #
Lincoln #
SAE
#
Descriptions
Type
Thread
FIG.Overall
Length
(O)

Shank
Length
(S)

Hex
Size
(H)

1921-S
N/A
H-230-SS-AM
1/8"-PTF 30 degree
30°
1/8"-PTF
21.25"
.34"
7/16"
1922-S
N/A
H-267-SS-AM
1/8"-PTF 67 1/2 degree
67°
1/8"-PTF
2.95"
.34"
7/16"
1923-S
N/A
H-290-SS-AM
1/8"-PTF 90 degree
90°
1/8"-PTF
3.82"
.27"
7/16"
1961-S
5000-9
H-200-SS-AM
1/8"-PTF straight
Straight
1/8"-PTF
1.62"
.25"
7/16"
1966-S
5010-9
H-100-SS-AM
1/4"-28 SAE straight
Straight
1/4"-28 Taper Thread
1.54"
.20"
5/16"
1968-S
5210-9
H-145-SS-AM
1/4"-28 45 degree
45°
1/4"-28 Taper Thread
2.88"
0.2''
3/8"
1969-S
5410-9
H-190-SS-AM
1/4"-28 90 degree
90°
1/4"-28 Taper Thread
3.69"
.20"
3/8"
N/A
5033-9
K-316-SS-AM
3/16"-DRIVE
Straight
3/16" Drive
4.50"
.21"
5/16"

Grease fittings tips

Before finding the right grease fitting, you must first determine what kind of grease fitting thread you will use. You can choose from several kinds of thread components available. The thread fittings are commonly used in the BSPP, BSPT, metric parallel, metric tapered, NPT/NPTF, and UN/UNF. 

After determining your fitting thread, then you can now choose from the many different kinds of grease fittings, according to each of their particular features. There are also various types of grease guns to use alongside grease fittings, including the lever, pistol-grip, pneumatic, and cordless guns. Most of these guns are appropriate to use for any application. 

More importantly, keeping your grease fitting in its tip-top shape will help maintain its effectiveness. Doing so will also help you save a ton of money in the long run. Here are some tips on how you can properly maintain your grease fitting.

  • Use a clean rag to wipe your fitting before installing it. A lint-free cloth would be the best for this job.
  • Regularly check your grease fittings and immediately replace any defective ones.
  • As much as possible, use a common fitting type and size for similar applications.
  • Use label tags to help you remember the type of grease the flows through each of your grease fittings.
  • Know the delivery capacity of your grease fitting and make sure not to exceed them.
  • Maintain your grease gun properly as well If you are using one. Avoid storing it in moist and dirty areas. Cover them with a thick cloth or store them inside a hard case if possible.
  • Exercise extra caution and take safety measures when using your grease gun and grease fitting.
  • After using your grease gun, always wipe down your fitting to avoid contamination of dirt and moisture.

FAQs

1. Why does my grease gun get stuck in the fitting?

The gun gets stuck in the fitting because it is clogged by debris or hardened grease. It would help if you clean grease fittings and grease guns before use to avoid the chances of dirt being brought inside the bearing. Make sure the fitting is free of dirt before locking the coupler to the zerk, and do not combine old grease with new grease. 

2. What do I do if my grease fitting won’t take grease?

Inspect the following if the grease fitting won’t take grease: If the fitting nipple is damaged, replace the fitting. But if the fitting is not damaged, it is obscured by debris that prevents the flow, and you should replace the fitting. If there seems to be no damage, then use an impact fitting cleaner to break down the clogs with compressed fluid chemically.

3. How to remove the grease gun from zerk fitting?

Make sure to release the pressure on the fitting by tilting the coupler at an angle to break the seal or loosening it with a wrench. Besides, after releasing the pressure, remember to twist the coupler back and forth. 

4. How to attach a grease gun to a zerk fitting?

First, make sure that the grease gun and the zerk are dirt-free before fastening the nozzle to the fitting. Then, angle the coupler to the fitting and press down. Secure the connection by tightening the nozzle on the fitting, and when the coupler clicks into place, start up the grease gun, and let the lubricant flow.

To sum up

Grease fittings offer us an easier way to keep machinery in good condition. However, we should also do our due diligence in finding the best ones for our needs. Therefore, you need to keep in mind the type of thread you need, your options, and correct their application.

We hope that this article has aided you through the grease fitting identification and selection process and finding the perfect grease fitting for your task! If you have any questions, leave us a comment now!

3 thoughts on “A-Z guide to grease fitting types, sizes and thread identification”

  1. This has to be one of the most robust resources talking about grease fittings. Excellent job, thanks for all of the work put into this!

  2. Pierre Jacques

    Thanks for clearing up all sorts of questions I had.
    One still remains, when a chart says “thread forming” does that imply that I wont have to run the tap? Lets say to correctly install an, 1/4″-28 UNF “thread forming” H-100-RLA SAE grease fitting.
    I have my trailer leaf spring bolts which are Grade 5 steel, to drill and tap.
    So if I dont have to tap, because of the “thread forming” capacity it would be much simpler.
    Thanks

    1. Hi Pierre Jacque,

      Thanks for asking. That’s correct. You don’t have to run the tap.

      The reason is that when installing with the thread forming, these fittings with specially hardened threads allow them to be screwed into a drilled hole. This will eliminate your tapping the hole.

      The “thread forming” fittings will create a force to rearrange their metal to meet their thread design. As a result, they can be easily replaced by other types of fittings.

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