M18 Threaded Inserts | McMaster-Carr

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DFARS Specialty Metals

48 Products

Key-Locking Threaded Inserts for Soft Metal

Add strong threads in soft metal, such as aluminum. The keys on these inserts drive into holes to hold more securely than thread-locking or helical inserts. They prevent slipping and rotating, so they’re stable enough for use in vehicle or aerospace parts that experience heavy vibration. These inserts are comparable to Keensert inserts.

To install, drill and tap a hole in your material. Then, thread the insert onto the installation tool and screw it into the hole. Place the tool over the keys and hit it with a hammer to drive them in.

Standard Wall—Stronger than thin-wall inserts, these are your go-to choice for threading most holes.

Black Phosphate-Coated Steel—These inserts resist occasional moisture.

18-8 Stainless Steel—The choice for wet and outdoor environments, these inserts resist rust and mild chemicals.

	Inserts									Installation Tools		Inserts with Installation Tools
								Each
	Thread Size	For Tap Thread Size	Installed Lg., mm	Drill Bit Size, mm	For Max. Hole Dia., mm	No. of Locking Keys		1-9	10-Up		Each	No. of Inserts Included		Each
Standard Wall







				Black Phosphate-Coated Steel

				M12 x 1.25 mm	M18 x 1.5 mm	18	16.75	16.75	4	90245A351	000000	000000	90699A623	000000	—	———	0


				M12 x 1.75 mm	M18 x 1.5 mm	18	16.75	16.75	4	90245A349	00000	00000	90699A623	00000	—	———	0
				M18 x 1.5 mm	M24 x 1.5 mm	24	22.5	22.5	4	90245A197	00000	00000	94010A350	00000	2	90245A321	000000




						18-8 Stainless Steel

						M12 x 1.25 mm	M18 x 1.5 mm	18	16.75	16.75	4	93340A104	00000	00000	90699A623	00000	—	———	0


						M12 x 1.75 mm	M18 x 1.5 mm	18	16.75	16.75	4	93340A103	00000	00000	90699A623	00000	—	———	0
						M18 x 1.5 mm	M24 x 1.5 mm	24	22.5	22.5	4	93715A665	00000	00000	94010A350	00000	2	93715A475	000000

Helical Threaded Insert Removal Tools

To remove installed helical inserts, place the tip of these tools into the insert and lightly strike the tool’s head. Then, turn the tool counterclockwise with pressure to extract the insert.

Narrow Profile—The tip of these tools has a narrower angle than standard removal tools to reduce the chance it will dig into your material’s surface when you strike the tool.

	Mfr.		Each
Standard Profile



	6-32, 6-40, 8-32, 8-36, 10-24, 10-32, 12-24, 1/4"-20, 1/4"-28, 5/16"-18, 5/16"-24, 3/8"-16, 3/8"-24, 7/16"-14, 7/16"-20, 1/2"-13, 1/2"-20, 9/16"-12, 9/16"-18, 5/8"-11, 5/8"-18, 3/4"-10, 3/4"-16, 7/8"-9, 7/8"-14, 1"-8, 1"-12, 1"-14, M4, M5, M6, M7, M8, M9, M10, M12, M13, M14, M15, M16, M18, M20, M22, M24	—	90254A113	000000


	Narrow Profile



			7/16"-14, 7/16"-20, 1/2"-13, 1/2"-20, 1/2"-28, 9/16"-12, 9/16"-18, 5/8"-11, 5/8"-18, 5/8"-24, 3/4"-10, 3/4"-16, 3/4"-20, 7/8"-9, 7/8"-14, 7/8"-20, 1"-8, 1"-12, 1"-14, M12, M14, M16, M18, M20, M22, M24	Heli-Coil	90254A330	00000

Thread-Locking Threaded Inserts

With Loctite® adhesive already on the threads, these inserts won’t back out or vibrate loose. The adhesive reaches full strength after 72 hours. Unlike helical inserts, you can install them with a standard drill and tap. However, thread-locking inserts are difficult to remove and reuse.

After drilling and tapping your hole, install inserts with a wrench or an installation bit. To use a wrench, thread an insert and two hex nuts onto a bolt. Then, grip and turn the top nut to drive into the hole. For slotted inserts, you can drive with a slotted screwdriver instead.

Standard Wall—Stronger than thin-wall inserts, these are your go-to choice for threading most holes.

Black Phosphate-Coated Steel—These inserts resist occasional moisture.

	Drill Bit Size	For Max. Hole Dia.	Pkg. Qty.		Pkg.
Standard Wall







	Black Phosphate-Coated Steel

	M14 x 1.25 mm	M18 x 1.5 mm	11.5 mm	16.5 mm	16.5 mm	1	97084A314	00000


	M18 x 1.5 mm	1"-12	0.453"	59/64"	0.922"	1	97084A316	0000

Key-Locking Threaded Insert Drivers

Place the tip of these tools into a key-locking insert after you've threaded it into a hole with your fingers. Then, strike these tools with a hammer to drive the keys into the material and secure the insert. They’re compatible with Keensert inserts.

Choose the tool that matches your insert’s thread size and tap thread size.

		Each
Metric Thread







	For Thick-Wall Inserts

	M12	M18	Straight	90699A623	000000


	M18	M24	Straight	94010A350	00000

Helical Threaded Inserts

Pronged

Restore, reinforce, or create threads in metal. The tough coils on these inserts expand once installed to anchor in a tapped hole. Also known as Heli-Coil inserts, they're often used in engine heads and machinery housings where strong connections are critical. Unlike threadlocking inserts, you can remove and reuse them without them losing their strength.

Installation requires a drill bit, a helical insert tap, and an installation tool.

Pronged—The prong attaches to an installation tool for precise control as you drive inserts in. Remove the prong with a punch or break-off tool before inserting a screw.

18-8 Stainless Steel—The choice for wet and outdoor environments, these inserts resist rust and mild chemicals.

	Inserts								Through-Hole Taps		Closed-End Hole Taps		Installation Tools		Inserts with Installation Tools
	Thread Size	Installed Lg., mm	Drill Bit Size	For Max. Hole Dia.	Specs. Met	Pkg. Qty.		Pkg.		Each		Each		Each	No. of Inserts Included		Each
Pronged







				18-8 Stainless Steel

				M18 x 2.5 mm	18	47/64"	0.734"	SAE MA3279-121	1	91732A677	00000	91709A373	0000000	91709A569	0000000	90261A312	0000000	—	———	0


				M18 x 2.5 mm	27	47/64"	0.734"	DIN 8140, SAE MA3279-171	1	91732A679	0000	91709A373	000000	91709A569	000000	90261A312	000000	6	91732A073	0000000

Extraction Tools

Remove installed helical inserts.

For Pronged Helical Inserts—Place the tip into pronged inserts and lightly strike the tool’s head. Then, turn the tool counterclockwise with pressure to extract the insert.

		Each
For Pronged Helical Inserts



	7/16"-14, 7/16"-20, 1/2"-13, 1/2"-20, 1/2"-28, 9/16"-12, 9/16"-18, 5/8"-11, 5/8"-18, 5/8"-24, 3/4"-10, 3/4"-16, 3/4"-20, 7/8"-9, 7/8"-14, 7/8"-20, 1"-8, 1"-12, 1"-14, M12, M14, M16, M18, M20, M22, M24	90254A330	000000

Helical Threaded Inserts For Spark Plug Repair


For Gasket Seats	For Gasket and Taper Seats

Replace stripped spark plugs in engines. These kits include helical inserts that fit common hole sizes, plus a tap and an installation tool. Also known as Heli-Coil inserts.

Inserts For Gasket Seats—Use these helical inserts in spark plug ports with a gasket. They cannot be used with taper seat ports.

18-8 Stainless Steel—The choice for wet and outdoor environments, these inserts resist rust and mild chemicals.

	Includes		Each
Inserts For Gasket Seats







	18-8 Stainless Steel

	M18 x 1.5 mm	Fine	24	Installation Tool M18×1.5 mm Thread × 1/2" Insert Reach (24 Each) Through-Hole Tap	91732A055	0000000

Helical Threaded Inserts with Installation Tools

Drill Bit, Installation Tool

and Through-Hole Tap

Quickly restore stripped threads—these inserts come with through-hole taps and installation tools. The tough coils on these inserts expand once installed to anchor in a tapped hole.

Pronged—The prong attaches to an installation tool for precise control as you drive inserts in. Remove the prong with a punch or break-off tool before inserting a screw.

18-8 Stainless Steel—The choice for wet and outdoor environments, these inserts resist rust and mild chemicals.

	For Max. Hole Dia.	No. of Inserts Included	Includes		Each
Pronged







	18-8 Stainless Steel

	M18 x 2.5 mm	27	47/64"	0.734"	6	Drill Bit Installation Tool Through-Hole Tap	91732A073	0000000

Screw-Locking Seize-Resistant Key-Locking Threaded Inserts for Soft Metal

Create the tightest hold in aluminum and other soft metal without screws sticking. The lubricant on these inserts eases installation, and the irregularly shaped threads won’t let screws back out from vibration. Inserts have keys that drive into material to prevent them from slipping or rotating in the hole.

Standard Wall—Stronger than thin-wall inserts, these are your go-to choice for threading most holes.

Dry-Film-Lubricated 18-8 Stainless Steel—The choice for wet and outdoor environments, these inserts resist rust and mild chemicals.

	Inserts								Installation Tools
	Thread Size	For Tap Thread Size	Installed Lg., mm	Drill Bit Size, mm	For Max. Hole Dia., mm	No. of Locking Keys		Each		Each
Standard Wall







				Dry-Film-Lubricated 18-8 Stainless Steel

				M12 x 1.75 mm	M18 x 1.5 mm	18	16.75	16.75	4	97255A198	000000	93904A792	000000

Helical Threaded Insert Installation Tools

T-Handle

Install your pronged helical inserts into tapped holes. Screw an insert onto these tools and drive them a quarter to half-turn below the material’s surface.

	Handle Style	For Use With		Each
Metric Thread



	M18 × 2.5 mm	T-Handle	Helical Inserts, Screw-Locking Helical Inserts	90261A312	0000000

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.

	OD, mm	Ht., mm	Threading	Thread Dp., mm	For Hole Dia., mm	Hex Key Size		Each
Alloy Steel



	M18 × 2.5 mm	25	30	Partially Threaded	15	26.1	5/8"	92066A123	000000

Key-Locking Threaded Inserts with Installation Tools

Paired with the right tool for installation, these inserts create strong threads in soft metal, such as aluminum. They have keys that drive into material to prevent inserts from slipping and rotating in the hole.

Standard Wall—Stronger than thin-wall inserts, these are your go-to choice for threading most holes.

Black Phosphate-Coated Steel—These inserts resist occasional moisture.

18-8 Stainless Steel—The choice for wet and outdoor environments, these inserts resist rust and mild chemicals.

	Drill Bit Size, mm	For Max. Hole Dia., mm	No. of Locking Keys	No. of Inserts Included		Each
Standard Wall







	Black Phosphate-Coated Steel

	M18 x 1.5 mm	M24 x 1.5 mm	24	22.5	22.5	4	2	90245A321	000000




			18-8 Stainless Steel

			M18 x 1.5 mm	M24 x 1.5 mm	24	22.5	22.5	4	2	93715A475	000000

Finish-Your-Own Key-Locking Threaded Inserts for Soft Metal

Tap the thread size you need into the solid body of these inserts. They’re a great choice when you need a custom combination of internal thread size and external diameter. Use them to repair or add new threads in soft metal, such as aluminum. They can also plug threaded holes without the hassle of welding. Keys on the inserts drive into material to prevent slipping and rotating in the hole.

Black Phosphate-Coated Steel—These inserts resist occasional moisture.

Certificates with a traceable lot number are available for these products. Download certificates from ORDER HISTORY after your order ships.

	Inserts								Installation Tools
	For Tap Thread Size	Installed Lg., mm	Max. Tapping Dia., mm	Drill Bit Size, mm	For Max. Hole Dia., mm	No. of Locking Keys		Each		Each
Standard Profile







				Black Phosphate-Coated Steel

				M18 x 1.5 mm	18	12	16.75	16.75	4	93774A290	000000	93741A290	0000000

Screw-Locking Helical Threaded Inserts

Pronged

The irregularly shaped threads tightly grip screws to prevent them from loosening or backing out under vibration. Use these inserts to create or repair threads in pumps and other machinery that shakes and rattles. Also known as Heli-Coil inserts.

Installation requires a drill bit, a helical insert tap, and an installation tool.

Pronged—The prong attaches to an installation tool for precise control as you drive inserts in. Remove the prong with a punch or break-off tool before inserting a screw.

18-8 Stainless Steel—The choice for wet and outdoor environments, these inserts resist rust and mild chemicals.

	Inserts								Through-Hole Taps		Closed-End Hole Taps		Installation Tools
	Thread Size	Installed Lg., mm	Drill Bit Size	For Max. Hole Dia.	Specs. Met	Pkg. Qty.		Pkg.		Each		Each		Each
Pronged







				18-8 Stainless Steel

				M18 x 2.5 mm	18	47/64"	0.734"	SAE MA3329-121	1	90296A419	00000	91709A373	0000000	91709A569	0000000	90261A312	0000000


				M18 x 2.5 mm	27	47/64"	0.734"	SAE MA3329-171	1	90296A422	0000	91709A373	000000	91709A569	000000	90261A312	000000

Key-Locking Threaded Insert Installation Tools


Style A	Style D

Thread inserts and drive down their keys with a single tool. These tools are compatible with Keensert inserts.

Threaded Insert Installation Tools

Style A

	For Tap Thread Size	Style	Features		Each
For Thick-Wall Inserts



	M12	M18	A	Slotted End	6721N87	000000

Threaded Insert Installation Tools with Spring

Style D

The tradespersons’ choice for installing Mil. Spec. inserts. A spring holds the sleeve under tension, so wobbles and jostles don’t interfere with a clean, professional install.

	For Tap Thread Size	Style	Features		Each
For Thick-Wall Inserts



	M12	M18	D	Sleeve, Slotted End	93904A792	000000


	M18	M24	D	Sleeve, Slotted End	93904A795	00000

Key-Locking Threaded Insert Blank Drivers

Hand thread an insert blank into a tapped hole before placing the tip of these tools on the insert. Strike the tool with a hammer to drive the keys into your material.

	Handle Style		Each
Metric Thread



	M18	Straight	93741A290	0000000

Easy-Start Helical Threaded Insert Installation Tools

These tools compress the diameter of your insert so it fits easily into a tapped hole. They’re the best choice for preventing misaligned or damaged threads—just make sure you have space to turn the crank. Screw or slide an insert onto your tool and drive it between a quarter-turn and half-turn below the surface. Also known as prewinders.

Threaded Insert Installation Tools with Depth Stop


T-Handle	Prong Slot Drive

Ensure consistent installation across multiple inserts. Set your desired installation depth, and the stop will prevent you from driving your insert any further.

Prong Slot Drive Helical Insert Tool—Install both left- and right-hand threaded inserts with any thread pitch. However, these tools don't align the threads like threaded-drive tools, so installation may be more difficult.

	Handle Style	Helical Insert Tool Drive Type	For Use With		Each
Metric Thread



	M18 × 2.5 mm	T-Handle	Prong Slot	Helical Inserts, Screw-Locking Helical Inserts	1338N72	0000000

Air-Powered Key-Locking Threaded Insert Installation Tools

Install key-locking inserts in a flash. Instead of threading and hammering inserts in by hand, these air-powered tools do both steps with the pull of a trigger. Release the trigger and the tool automatically resets, ready for the next insert. They’re compatible with Keensert inserts.

				Air Inlet
Threaded Insert Tool Cycle Time, sec.	Max. Speed @ 90 psi, rpm	Wt., lb.	Average Air Consumption @ Pressure	Pipe Size	Thread Type	Gender	Includes	Container Type		Each
10	2,000	4.4	1.4 ft³/min @ 90 psi	1/4	NPTF	Female	One Nosepiece for 1/4-20 Thread Size One Nosepiece for 3/8-16 Thread Size One Nosepiece for 5/16-18 Thread Size One Nosepiece for 10-24 Thread Size	Plastic Case	91456A121	000000000

Threaded Insert Installation Tool Nosepieces

Choose a nosepiece that matches the internal thread size of your insert.

	For Tap Thread Size		Each
For Thin-Wall Inserts, Thick-Wall Inserts, and Extra-Thick-Wall Inserts



	10-24	5/16"-18, 3/8"-16, 7/16"-14	91456A211	0000000


	10-32	5/16"-18, 3/8"-16, 7/16"-14	91456A212	000000
	1/4"-20	3/8"-16, 7/16"-14, 1/2"-13	91456A213	000000
	1/4"-28	3/8"-16, 7/16"-14, 1/2"-13	91456A214	000000
	5/16"-18	7/16"-14, 1/2"-13, 9/16"-12	91456A215	000000
	5/16"-24	7/16"-14, 1/2"-13, 9/16"-12	91456A216	000000
	3/8"-16	1/2"-13, 9/16"-12, 5/8"-11	91456A217	000000
	3/8"-24	1/2"-13, 9/16"-12, 5/8"-11	91456A218	000000
	1/2"-13	5/8"-11, 11/16"-11, 13/16"-16	91456A219	000000
	1/2"-20	5/8"-11, 11/16"-11, 13/16"-16	91456A221	000000
	M5 × 0.8 mm	M8 × 1.25 mm, M10 × 1.25 mm	91456A621	000000


	M6 × 1 mm	M10 × 1.25 mm, M12 × 1.25 mm	91456A622	000000
	M8 × 1.25 mm	M12 × 1.25 mm, M14 × 1.5 mm	91456A623	000000
	M10 × 1.5 mm	M14 × 1.5 mm, M16 × 1.5 mm	91456A624	000000
	M12 × 1.75 mm	M16 × 1.5 mm, M18 × 1.5 mm	91456A625	000000

Helical Threaded Insert Installation and Prong Break-Off Tools

T-Handle

Install helical inserts and break off prongs with one tool and a hammer strike. These tools have a slot that grips your insert’s prong for turning both left- and right-hand threads. Slide an insert onto these tools and drive them a quarter-turn to half-turn below the material’s surface. Then, strike the end of the tool with a hammer to break off the prong. These tools work with pronged helical inserts.

For Pipe Size	Handle Style		Each



3/4"-10, M18 × 1.5 mm, M18 × 2 mm, M18 × 2.5 mm	3/8 BSPP	T-Handle	92450A186	000000