M8 Grease Fittings | McMaster-Carr

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44 Products

Grease Fitting Size Identifiers

Take the guesswork out of determining the thread type and size of a grease fitting. Screw the shank of a grease fitting into the labeled holes of these identifiers until you find the one that fits.

	For Thread Size	For Screw Size	For Pipe Size	Wd.	Ht.	Thk.		Each
Inch/Metric







	Aluminum

	Grease Fittings	NPT, SAE-LT, BSW, UNF, BSPT, BSF, Metric	External	3/16"-32, 1/4"-20, 1/4"-26, 1/4"-28, 5/16"-18, 5/16"-22, 5/16"-24, 3/8"-20, 3/8"-24, 1/2"-12, M6 × 0.75 mm, M6 × 1 mm, M8 × 1 mm, M8 × 1.25 mm, M10 × 1 mm, M10 × 1.5 mm	1/8", 1/4"	1/8, 1/4, 3/8	8 1/2"	3"	1/4"	0000000	000000

Grease Fittings

Thread these fittings into motors, bearings, engine blocks, and other machinery to create a lubrication point. They’re also known as hydraulic grease fittings.

Straight with Male Thread

Zinc-Plated Steel—Zinc-plated steel fittings have mild corrosion resistance.

Brass—Brass fittings resist corrosion better than zinc-plated steel fittings.

303 Stainless Steel—303 stainless steel fittings are more corrosion resistant than brass fittings and have good chemical resistance.

316 Stainless Steel—316 stainless steel fittings resist corrosion and chemicals better than 303 stainless steel fittings and can be used in saltwater environments.

Ball Check Valve—Fittings with a check valve prevent grease from leaking when pressure causes backward flow. The valve stays closed when not in use to keep out dirt and other contaminants.

											Pkg.
	Material	Overall Ht., mm	Thread Lg., mm	Shank Lg., mm	Hex Size, mm	Max. Pressure, psi	Check Valve Type	Specs. Met	Pkg. Qty.		1-9	10-Up
M8 × 0.75 mm Metric Thread



		Zinc-Plated Steel	15	5.5	5.5	9	1,450	Ball	DIN 71412	10	00000000	00000	00000


		M8 × 1 mm Metric Thread



				Zinc-Plated Steel	15	5.6	5.6	9	8,000	Ball	DIN 71412	10	0000000	0000	0000


				Zinc-Plated Steel	18.5	8.5	8.5	9	1,450	Ball	DIN 71412	10	00000000	0000	0000
				Brass	15	5.5	5.5	9	10,000	Ball	DIN 71412	5	0000000	0000	0000
				303 Stainless Steel	15	5.8	5.8	9	8,000	Ball	—	1	0000000	0000	0000
				316 Stainless Steel	15	5.5	5.5	9	1,450	Ball	DIN 71412	1	0000000	0000	0000


				M8 × 1.25 mm Metric Thread



						Zinc-Plated Steel	15	5.8	5.8	9	8,000	Ball	DIN 71412	10	0000000	0000	0000


						Brass	15	5.5	5.5	9	10,000	Ball	DIN 71412	5	0000000	0000	0000
						303 Stainless Steel	15	5.8	5.8	9	8,000	Ball	—	1	0000000	0000	0000
						316 Stainless Steel	15	5.5	5.5	9	1,450	Ball	DIN 71412	1	0000000	0000	0000

90° Elbow with Male Thread

Zinc-Plated Steel—Zinc-plated steel fittings have mild corrosion resistance.

Brass—Brass fittings resist corrosion better than zinc-plated steel fittings.

303 Stainless Steel—303 stainless steel fittings are more corrosion resistant than brass fittings and have good chemical resistance.

Ball Check Valve—Fittings with a check valve prevent grease from leaking when pressure causes backward flow. The valve stays closed when not in use to keep out dirt and other contaminants.

											Pkg.
	Material	Overall Ht., mm	Thread Lg., mm	Shank Lg., mm	Hex Size, mm	Max. Pressure, psi	Check Valve Type	Specs. Met	Pkg. Qty.		1-9	10-Up
M8 × 0.75 mm Metric Thread



		Zinc-Plated Steel	18	5.5	5.5	9	1,450	Ball	DIN 71412	10	00000000	000000	000000


		M8 × 1 mm Metric Thread



				Zinc-Plated Steel	18	5.5	5.5	9	8,000	Ball	DIN 71412	10	0000000	00000	00000


				Brass	18	5.5	5.5	9	10,000	Ball	DIN 71412	1	0000000	0000	0000
				303 Stainless Steel	18	5.6	5.6	9	8,000	Ball	—	1	0000000	0000	0000


				M8 × 1.25 mm Metric Thread



						Zinc-Plated Steel	18	5.6	5.6	9	8,000	Ball	—	10	0000000	00000	00000


						Brass	18	5.5	5.5	9	10,000	Ball	DIN 71412	3	0000000	00000	00000
						303 Stainless Steel	18	5.5	5.5	9	8,000	Ball	—	1	0000000	0000	0000

67° Elbow with Male Thread

Zinc-Plated Steel—Zinc-plated steel fittings have mild corrosion resistance.

Ball Check Valve—Fittings with a check valve prevent grease from leaking when pressure causes backward flow. The valve stays closed when not in use to keep out dirt and other contaminants.

											Pkg.
	Material	Overall Ht., mm	Thread Lg., mm	Shank Lg., mm	Hex Size, mm	Max. Pressure, psi	Check Valve Type	Specs. Met	Pkg. Qty.		1-9	10-Up
M8 × 1 mm Metric Thread



		Zinc-Plated Steel	20.5	5.5	5.5	9	1,450	Ball	DIN 71412	10	00000000	000000	000000


		M8 × 1.25 mm Metric Thread



				Zinc-Plated Steel	20.5	5.5	5.5	9	1,450	Ball	DIN 71412	10	00000000	00000	00000

45° Elbow with Male Thread

Zinc-Plated Steel—Zinc-plated steel fittings have mild corrosion resistance.

Brass—Brass fittings resist corrosion better than zinc-plated steel fittings.

303 Stainless Steel—303 stainless steel fittings are more corrosion resistant than brass fittings and have good chemical resistance.

Ball Check Valve—Fittings with a check valve prevent grease from leaking when pressure causes backward flow. The valve stays closed when not in use to keep out dirt and other contaminants.

											Pkg.
	Material	Overall Ht., mm	Thread Lg., mm	Shank Lg., mm	Hex Size, mm	Max. Pressure, psi	Check Valve Type	Specs. Met	Pkg. Qty.		1-9	10-Up
M8 × 0.75 mm Metric Thread



		Zinc-Plated Steel	23.5	5.5	5.5	9	1,450	Ball	DIN 71412	10	00000000	000000	00000


		M8 × 1 mm Metric Thread



				Zinc-Plated Steel	23	5.5	5.5	9	8,000	Ball	DIN 71412	10	0000000	00000	00000


				Brass	24	5.5	5.5	9	10,000	Ball	DIN 71412	5	0000000	00000	00000
				303 Stainless Steel	22	5.6	5.6	9	8,000	Ball	—	3	0000000	00000	00000


				M8 × 1.25 mm Metric Thread



						Zinc-Plated Steel	23	5.6	5.6	9	8,000	Ball	—	10	0000000	00000	00000


						Brass	24	5.5	5.5	9	10,000	Ball	DIN 71412	1	0000000	0000	0000
						303 Stainless Steel	22	5.5	5.5	9	8,000	Ball	—	1	0000000	0000	0000

90° Wye with Male Thread

Zinc-Plated Steel—Zinc-plated steel fittings have mild corrosion resistance.

Ball Check Valve—Fittings with a check valve prevent grease from leaking when pressure causes backward flow. The valve stays closed when not in use to keep out dirt and other contaminants.

											Pkg.
	Material	Overall Ht., mm	Thread Lg., mm	Shank Lg., mm	Max. Pressure, psi	Square Size, mm	Check Valve Type	Specs. Met	Pkg. Qty.		1-9	10-Up
M8 × 1 mm Metric Thread



		Zinc-Plated Steel	18	5.5	5.5	1,450	9	Ball	DIN 71412	5	00000000	000000	000000


		M8 × 1.25 mm Metric Thread



				Zinc-Plated Steel	18	5.5	5.5	1,450	9	Ball	DIN 71412	5	00000000	00000	00000

Grease Fitting Adapters

When the size or thread type of a fitting doesn't match an existing opening, use these adapters to make the connection.

Straight

UNF Thread—UNF threads are similar to threads on a machine screw or bolt. They require a sealant, such as an O-ring, to minimize leakage.

Zinc-Plated Steel—Zinc-plated steel adapters have mild corrosion resistance.

Brass—Brass adapters resist corrosion better than zinc-plated steel adapters.

Connection
Male	Female	Material		Each



	Metric M8 × 1 mm	UNF 1/4"-28	Zinc-Plated Steel	0000000	00000


	Metric M8 × 1 mm	NPT 1/8	Brass	00000000	00000
	Metric M8 × 1 mm	BSPT 1/8	Brass	00000000	00000
	Metric M8 × 1.25 mm	NPT 1/8	Brass	00000000	00000

Button Head Grease Fittings

Often used on earth movers, mining equipment, and other heavy machinery, these fittings have a T-shaped top that holds the dispensing tip in place so it won’t pop off when adding grease. They're best for machinery requiring high volumes of grease because they let more grease pass through than standard grease fittings, thanks to a larger opening. An integral check valve prevents grease from leaking when pressure causes backward flow. The valve stays closed when not in use to keep out dirt and other contaminants.

Straight with Male Thread

Image of Product. Front orientation. Grease Fittings. Button Head Grease Fittings, Male, Straight.

Zinc-Plated Steel—Zinc-plated steel fittings have mild corrosion resistance.

303 Stainless Steel—303 stainless steel fittings are more corrosion resistant than zinc-plated steel fittings and have good chemical resistance.

											Each
	Material	Overall Ht., mm	Thread Lg., mm	Shank Lg., mm	Hex Size, mm	Head Dia., mm	Max. Pressure, psi	Check Valve Type	Specs. Met		1-9	10-Up
M8 × 1 mm Metric Thread



		Zinc-Plated Steel	14	6	6	11	10	1,450	Ball	DIN 3404	0000000	00000	00000


		Zinc-Plated Steel	17	6	6	17	16	10,000	Ball	DIN 3404	0000000	0000	0000
		303 Stainless Steel	17	6	6	17	16	10,000	Ball	DIN 3404	0000000	00000	00000


		M8 × 1.25 mm Metric Thread



				Zinc-Plated Steel	17	6	6	17	16	1,450	Ball	DIN 3404	0000000	0000	0000

Flush-Style Grease Fittings


Male Straight Style C	Male Straight Style D

The nipple doesn't stick out, so these fittings fit in tight spaces and won't be damaged if something knocks into them. An integral check valve prevents grease from leaking when pressure causes backward flow. The valve stays closed when not in use to keep out dirt and other contaminants.

Straight with Male Thread


Style C	Style D

Style C—Install Style C with a hex wrench.

Style D—Install Styles A, B, and D with a slotted screwdriver.

Zinc-Plated Steel—Zinc-plated steel fittings have mild corrosion resistance.

													Pkg.
	Style	Material	Overall Ht., mm	Thread Lg., mm	Shank Lg., mm	Slot Lg., mm	Hex Size, mm	Max. Pressure, psi	Check Valve Type	Specs. Met	Pkg. Qty.		1-9	10-Up
M8 × 1 mm Metric Thread



		C	Zinc-Plated Steel	9.5	6.5	6.5	—	9	10,000	Ball	DIN 3405	5	0000000	00000	00000


		D	Zinc-Plated Steel	10	10	10	8	—	1,450	Ball	DIN 3405	5	00000000	00000	00000


		M8 × 1.25 mm Metric Thread



				C	Zinc-Plated Steel	9.5	6.5	6.5	—	9	1,450	Ball	DIN 3405	5	00000000	0000	0000

Self-Tapping Grease Fittings for Unthreaded Holes

To fit securely in unthreaded holes, these fittings cut threads as they’re installed. Use a hex wrench to install. Fittings can be driven in, but then are not pressure rated. They're zinc-plated steel for mild corrosion resistance. All have an integral check valve that prevents grease from leaking when pressure causes backward flow. The valve stays closed when not in use to keep out dirt and other contaminants. These fittings are also known as hydraulic grease fittings.

Straight with Male Thread

											Pkg.
	For Hole Dia., mm	Material	Overall Ht., mm	Shank Lg., mm	Thread Lg., mm	Hex Size, mm	Max. Pressure, psi	Check Valve Type	Pkg. Qty.		1-9	10-Up
M8 × 1 mm Metric Thread



		7.6 to 7.7	Zinc-Plated Steel	15	5.5	5.5	9	10,000	Ball	10	0000000	00000	00000

90° Elbow with Male Thread

											Pkg.
	For Hole Dia., mm	Material	Overall Ht., mm	Shank Lg., mm	Thread Lg., mm	Square Size, mm	Max. Pressure, psi	Check Valve Type	Pkg. Qty.		1-9	10-Up
M8 × 1 mm Metric Thread



		7.6 to 7.7	Zinc-Plated Steel	18	5.5	5.5	9	10,000	Ball	5	0000000	000000	00000

45° Elbow with Male Thread

											Pkg.
	For Hole Dia., mm	Material	Overall Ht., mm	Shank Lg., mm	Thread Lg., mm	Square Size, mm	Max. Pressure, psi	Check Valve Type	Pkg. Qty.		1-9	10-Up
M8 × 1 mm Metric Thread



		7.6 to 7.7	Zinc-Plated Steel	20	5.5	5.5	9	10,000	Ball	5	0000000	000000	000000

Self-Tapping Flush-Style Grease Fittings for Unthreaded Holes

Ensure a secure fit in unthreaded holes—these fittings cut threads as they’re installed. Use them in tight spaces where protruding fittings won't work. Install with a hex wrench. Fittings can be driven in, but then are not pressure rated. They’re zinc-plated steel for mild corrosion resistance. An integral check valve prevents grease from leaking when pressure causes backward flow. The valve stays closed when not in use to keep out dirt and other contaminants.

												Pkg.
	For Hole Dia., mm	Material	Overall Ht., mm	Shank Lg., mm	Thread Lg., mm	Hex Size, mm	Max. Pressure, psi	Check Valve Type	Specs. Met	Pkg. Qty.		1-9	10-Up
Straight with Male Thread







				M8 × 1 mm Metric Thread

				7.6 to 7.7	Zinc-Plated Steel	8.5	5.5	5.5	9	10,000	Ball	DIN 3405	3	0000000	00000	00000