M18 Reducers | McMaster-Carr

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	System of Measurement System of Measurement

Metric

	Thread Size Thread Size	Show

M18

	Thread Size Thread Size	Hide

	Thread Pitch Thread Pitch

1.5 mm

2.5 mm

	Thread Type Thread Type

Metric

	Threaded Insert Type Threaded Insert Type


Thread Locking	Helical

Key Locking

	Material Material

Aluminum

Stainless Steel

Steel

	Installed Length Installed Length

	For Tap Thread Size For Tap Thread Size

1"-12

M24

	Thread Spacing Thread Spacing

Coarse

Fine

	Thread Direction Thread Direction

	Right Hand

	For Tap Type For Tap Type

Standard (UN)

Helical

Metric

	REACH (Registration, Evaluation, Authorization and Restriction of Chemicals) REACH (Registration, Evaluation, Authorization and Restriction of Chemicals)

REACH Compliant

	RoHS (Restriction of Hazardous Substances) RoHS (Restriction of Hazardous Substances)

RoHS Compliant

RoHS Compliant with
Exemptions

	For Use In For Use In

Metal

	End Type End Type

Open

	Tensile Strength Tensile Strength

60,000 psi

200,000 psi

Not Rated

	For Maximum Hole Diameter For Maximum Hole Diameter

0.5" to 0.999"

20 mm to 24.99 mm

	Helical Insert Style Helical Insert Style

With Prong

	Drill Bit Size Drill Bit Size

47/64"

59/64"

22.5 mm

	For Minimum Material Thickness For Minimum Material Thickness

	DFARS (Defense Acquisition Regulations Supplement) DFARS (Defense Acquisition Regulations Supplement)

DFARS Specialty Metals
COTS-Exempt

DFARS Specialty Metals
Compliant

	Number of Inserts Included Number of Inserts Included

	Passivation Passivation

Not Passivated

Passivated

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18 Products

How to Measure Threaded Pipe Size

About Nuts, Materials, and Finishes

How to Install Key-Locking Inserts

How to Install Helical Inserts

About Helical Insert Length

Low-Profile Hex Manifolds

When you’re short on vertical space, these manifolds are a good fit—they have outlets on the side instead of on top, so they have a lower profile than rectangular manifolds. Use them to distribute air, water, or hydraulic fluid to five locations from a single supply source. Manifolds have mounting holes, so you can mount from the top.

Anodized aluminum manifolds are the industry standard for the most common types of applications. They are lighter in weight than other metal manifolds and have good corrosion resistance. These manifolds are anodized for a black finish.

316 stainless steel manifolds have excellent corrosion resistance and can handle fuel, gasoline, coolant and other harsh substances.

For technical drawings and 3-D models, click on a part number.

Anodized Aluminum—Metric Inlets × Metric Outlets

For Use With: Air, Water, Hydraulic Fluid
Temperature Range: -10° to 200° F
Maximum Pressure: 1,000 psi @ 72° F
Maximum Vacuum: 27 in. of Hg @ 72° F

	Inlet		Outlet
No. of Outlets	Thread Size	Thread Pitch, mm	Thread Size	Thread Pitch, mm	Wd., mm	Ht., mm	Outlet Spacing	Color		Each
5	M20	1.5	M18	1.5	50	31	Standard	Black	00000000	0000000

316 Stainless Steel—Metric Inlets × Metric Outlets

For Use With: Air, Water, Hydraulic Fluid, Alcohol, Coolant, Cutting Oil, Deionized Water, Diesel Fuel, Fuel Oil, Gasoline, Mineral Oil, Nitrogen
Temperature Range: 100° to 500° F
Maximum Pressure: 3,500 psi @ 72° F
Maximum Vacuum: 27 in. of Hg @ 72° F

	Inlet		Outlet
No. of Outlets	Thread Size	Thread Pitch, mm	Thread Size	Thread Pitch, mm	Wd., mm	Ht., mm	Outlet Spacing		Each
5	M20	1.5	M18	1.5	50	31	Standard	00000000	0000000

Black-Phosphate Steel Easy-to-Install Thread-Locking Inserts

A black-phosphate finish provides mild corrosion resistance. Also known as E-Z Lok, these inserts use Loctite® adhesive to keep them in place. The adhesive reaches full strength after 72 hours. Installation requires a drill bit and a standard tap. Then set the insert with a bolt and two nuts, or use an installation bit.

Choose inserts with a thick wall for greater strength than thin-wall inserts, or to fill a large hole.

For technical drawings and 3-D models, click on a part number.

Metric

			For Tap
Thread Size	Thread Pitch, mm	Thread Spacing	Thread Size	Installed Lg.	Drill Bit Size	For Max. Hole Dia.	Pkg. Qty.		Pkg.
Black-Phosphate Steel with Thick Wall
M18	1.5	Fine	1"-12	29/64"	59/64"	59/64"	1	000000000	00000

18-8 Stainless Steel Key-Locking Inserts

Made of stainless steel, these inserts have good corrosion resistance. Drive the keys into the surrounding material for a more secure hold than thread-locking inserts. Use them to repair or change threads in soft metals such as aluminum. Inserts may be mildly magnetic. They’re comparable to Keensert® inserts. Installation requires a drill bit, a standard tap, an installation tool, and a hammer.

Choose inserts with a thick wall for greater strength than thin-wall inserts, or to fill a large hole.

For technical drawings and 3-D models, click on a part number.

Metric

Inserts
			For Tap							Each		Installation Tools
Thread Size	Thread Pitch, mm	Thread Spacing	Thread Size	Thread Pitch, mm	Installed Lg.	Drill Bit Size	For Max. Hole Dia.	No. of Locking Keys		1-9	10-Up		Each
18-8 Stainless Steel with Thick Wall
M18	1.5	Fine	M24	1.5	24mm	22.5 mm	22.5mm	4	000000000	000000	000000	000000000	000000

Black-Phosphate Steel Key-Locking Inserts

A black-phosphate finish provides mild corrosion resistance. Drive the keys into the surrounding material for a more secure hold than thread-locking inserts. Use them to repair or change threads in soft metals such as aluminum. They’re comparable to Keensert® inserts. Installation requires a drill bit, a standard tap, an installation tool, and a hammer.

Choose inserts with a thick wall for greater strength than thin-wall inserts, or to fill a large hole with stripped threads.

For technical drawings and 3-D models, click on a part number.

Metric

Inserts
			For Tap							Each		Installation Tools
Thread Size	Thread Pitch, mm	Thread Spacing	Thread Size	Thread Pitch, mm	Installed Lg.	Drill Bit Size	For Max. Hole Dia.	No. of Locking Keys		1-9	10-Up		Each
Black-Phosphate Steel with Thick Wall
M18	1.5	Fine	M24	1.5	24mm	22.5 mm	22.5mm	4	000000000	000000	000000	000000000	000000

Stainless Steel Screw-Locking Helical Inserts

A distorted thread grips the screw to resist loosening. Also known as Heli-Coil inserts, these inserts have coils that expand once installed to securely anchor the insert. All have a prong for ease of installation. An installation tool grips the prong and reduces the coil diameter, enabling the insert to fit in tapped holes. Remove the prong to insert the screw. Installation requires a drill bit, a helical insert tap, an installation tool, and a prong break-off tool.

For technical drawings and 3-D models, click on a part number.

Metric

Inserts										Through-Hole Taps		Closed-End Hole Taps		Installation Tools
Thread Size	Thread Pitch, mm	Thread Spacing	Installed Lg., mm	Drill Bit Size	For Max. Hole Dia.	Specifications Met	Pkg. Qty.		Pkg.		Each		Each		Each
18-8 Stainless Steel
M18	2.5	Coarse	18	47/64"	47/64"	SAE MA3329-121	1	000000000	00000	000000000	0000000	000000000	0000000	000000000	0000000
M18	2.5	Coarse	27	47/64"	47/64"	SAE MA3329-171	1	000000000	0000	000000000	000000	000000000	000000	000000000	000000

Stainless Steel Helical Inserts

Also known as Heli-Coil inserts, these inserts have coils that expand once installed to securely anchor the insert. All have a prong for ease of installation. An installation tool grips the prong and reduces the coil diameter, enabling the insert to fit in tapped holes. Remove the prong to insert the screw. Installation requires a drill bit, a helical insert tap, an installation tool, and a prong break-off tool.

Inserts that meet DIN 8140 adhere to international standards for dimensions.

For technical drawings and 3-D models, click on a part number.

Metric

Inserts										Through-Hole Taps		Closed-End Hole Taps		Installation Tools
Thread Size	Thread Pitch, mm	Thread Spacing	Installed Lg., mm	Drill Bit Size	For Max. Hole Dia.	Specifications Met	Pkg. Qty.		Pkg.		Each		Each		Each
18-8 Stainless Steel—Right-Hand Threaded
M18	2.5	Coarse	18	47/64"	47/64"	SAE MA3279-121	1	000000000	00000	000000000	0000000	000000000	0000000	000000000	0000000
M18	2.5	Coarse	27	47/64"	47/64"	DIN 8140, SAE MA3279-171	1	000000000	0000	000000000	000000	000000000	000000	000000000	000000

Helical Inserts with Installation Tools

Shown with Five Inserts and Drill Bit

Inserts come with a through-hole tap and installation tool. Also known as Heli-Coil inserts, they have coils that expand once installed to securely anchor the insert. All have a prong for ease of installation. An installation tool grips the prong and reduces the coil diameter, enabling the insert to fit in tapped holes. Remove the prong to insert the screw.

Metric

18-8 Stainless Steel—Right-Hand Threaded
Thread Size	Thread Pitch, mm	Thread Spacing	Installed Lg., mm	Drill Bit Size	For Max. Hole Dia.	No. of Inserts Included	Includes		Each
M18	2.5	Coarse	27	47/64"	47/64"	6	Drill Bit, Through-Hole Tap, Installation Tool	000000000	0000000

Key-Locking Inserts with Installation Tool

Drive the keys into the surrounding material for a more secure hold than thread-locking inserts. These inserts are used to repair or convert threads in soft metals such as aluminum. They’re comparable to Keensert® inserts.

18-8 stainless steel inserts are more corrosion resistant than black-phosphate steel. They may be mildly magnetic.

Black-phosphate steel inserts are mildly corrosion resistant.

Choose inserts with a thick wall for greater strength than thin-wall inserts, or to fill a large hole.

For technical drawings and 3-D models, click on a part number.

Metric

			For Tap
Thread Size	Thread Pitch, mm	Thread Spacing	Thread Size	Thread Pitch, mm	Installed Lg.	Drill Bit Size	For Max. Hole Dia.	No. of Locking Keys	No. of Inserts Included		Each
18-8 Stainless Steel with Thick Wall
M18	1.5	Fine	M24	1.5	24mm	22.5 mm	22.5mm	4	2	000000000	000000
Black-Phosphate Steel with Thick Wall
M18	1.5	Fine	M24	1.5	24mm	22.5 mm	22.5mm	4	2	000000000	00000

Spark Plug Thread Repair Kits

Kits include helical inserts, a tap, and an installation tool. Also known as Heli-Coil inserts, they have coils that expand once installed to securely anchor the insert. All have a prong for ease of installation. An installation tool grips the prong and reduces the coil diameter, enabling the insert to fit in tapped holes. Remove the prong to insert the screw.

18-8 Stainless Steel
Includes	No. of Inserts Included		Each
M18×1.5 mm Thread × 1/2" Insert Reach (24 Each) Through-Hole Tap Installation Tool	24	000000000	0000000

Alloy Steel Socket Nuts

Also known as Allen nuts, use these with socket head cap screws in recessed holes and tight spaces that don't have enough clearance for a wrench. Tighten them with a 6-point hex key. They can also be used as an insert by pressing or drawing them into nonhardened steel, cast iron, or soft nonferrous metal or by molding them into plastic, ceramic, fiber, and similar materials. Made from alloy steel, they're comparable in strength to Grade 9 bolts.

For technical drawings and 3-D models, click on a part number.

Alloy Steel
Thread Size	Thread Pitch	OD	Ht.	Threading	Thread Dp.	For Hole Dia.	Hex Key Size	Pkg. Qty.		Pkg.
M18	2.5 mm	25mm	30mm	Partially Threaded	15mm	26.1mm	5/8"	1	000000000	000000