M2 Helicoils | McMaster-Carr

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21 Products

Helical Threaded Inserts


Pronged	Prongless

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.

Prongless—Without a prong to break off and retrieve, these inserts save time and avoid leftover debris in holes.

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		Prong Break-Off Tools
	Thread Size	Installed Lg., mm	Drill Bit Size, mm	For Max. Hole Dia., mm	Specs. Met	Pkg. Qty.		Pkg.		Each		Each		Each		Each
Pronged







				18-8 Stainless Steel

				M2 x 0.4 mm	2	2.1	2.1	DIN 8140, SAE MA3279-140	10	91732A181	00000	91709A240	0000000	91709A230	0000000	90261A185	0000000	92955A206	0000000


				M2 x 0.4 mm	3	2.1	2.1	DIN 8140, SAE MA3279-190	10	91732A182	0000	91709A240	000000	91709A230	000000	90261A185	000000	92955A206	000000
				M2 x 0.4 mm	4	2.1	2.1	DIN 8140, SAE MA3279-240	10	91732A183	0000	91709A240	000000	91709A230	000000	90261A185	000000	92955A206	000000


				Prongless







								18-8 Stainless Steel

								M2 x 0.4 mm	2	2.1	2.1	—	5	91990A507	0000	91709A240	000000	91709A230	000000	91049A102	000000	———	0


								M2 x 0.4 mm	3	2.1	2.1	—	5	91990A508	0000	91709A240	000000	91709A230	000000	91049A102	000000	———	0
								M2 x 0.4 mm	4	2.1	2.1	—	5	91990A509	0000	91709A240	000000	91709A230	000000	91049A102	000000	———	0

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.

For Prongless Helical Inserts—Remove prongless inserts without damaging threads or the surface of your material. These tools also back out or adjust inserts that are installed too deep.

		Each
For Pronged Helical Inserts



	1-64, 1-72, M2	90254A370	0000000


	For Prongless Helical Inserts



			M2	91049A378	000000

Helical Insert Taps

Match the size of helical inserts so they fit tightly when installed in the hole.

High-Speed Steel—These taps resist heat and wear to stay sharp.

Plug Chamfer—Our go-to chamfer type. With a longer taper than a bottoming chamfer, they are easier to turn but won't thread as close the bottom of a hole.

Bottoming Chamfer—Cut all the way to the bottom of blind holes with taps that have the shortest taper. Since these require the most force to turn, they’re often used to finish holes started by taper- or plug-chamfer taps.

						Drill Bit			Plug Chamfer		Bottoming Chamfer
	For Insert Size	Thread Lg.	Overall Lg.	For Insert Thread Type	No. of Flutes	Size, mm	Decimal Size Equiv.	Shank Type		Each		Each
High-Speed Steel







				Uncoated

				M2	1/2"	1 13/16"	Metric	3	2.1	0.0827"	Square	91709A240	0000000	91709A230	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	Threaded Drive

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

Threaded Drive Helical Insert Tool—These tools align each coil of your insert perfectly with the thread pitch of your tapped hole for easy installation.

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



	M2 × 0.4 mm	Heli-Coil	T-Handle	Threaded	Helical Inserts, Screw-Locking Helical Inserts	90261A185	0000000

Lubricant-Free Seize-Resistant Helical Threaded Inserts

No lubricant means no mess or particles to contaminate environments such as clean rooms and labs. These inserts are made of Nitronic 60 stainless steel, which prevents sticking or binding that wears out the threads. They're ideal for parts that require frequent disassembly for inspection or repair. 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.

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







				Nitronic 60 Stainless Steel

				M2 x 0.4 mm	3	2.1	2.1	5	93914A413	00000	91709A240	0000000	91709A230	0000000	90261A185	0000000	92955A206	0000000

Prongless Helical Threaded Insert Installation Tools

These tools install prongless helical inserts, also known as tangless inserts. Screw the insert onto your installation tool and drive it between a quarter-turn and half-turn below the surface.

	Handle Style	For Use With		Each
Metric Thread



	M2 × 0.4 mm	Straight	Helical Inserts	91049A102	0000000

Replacement Tips

For Thread Size		Each
M2	91049A203	000000

Spring-Loaded Helical Threaded Insert Prong Break-Off Tools

Cleanly snap prongs off installed helical inserts with just one hand. Because they work faster than standard prong break-off tools, these are a good choice when you have many prongs to remove. Press your tool into an insert to trigger the spring-loaded punch and snap off the prong.

For Standard-Length Inserts—Use these tools for inserts that are 1 to 2 times as long as the diameter.

For Long Inserts—Use these tools for inserts that are 2 _1/2 to 3 times as long as the diameter.

	Mfr.		Each
For Standard-Length Inserts



	2-56, 3-48, 3-56, M2, M2.2	—	92955A311	000000


	M2	Heli-Coil	92955A206	000000


	For Long Inserts



			2-56, M2, M2.2	—	92955A411	00000

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



	2-56, 3-48, 3-56, 4-40, 4-48, 5-40, 6-32, 6-40, 8-32, 8-36, M2, M2.2, M2.5, M3, M3.5, M4	—	90254A111	000000


	Narrow Profile



			1-64, 1-72, M2	Heli-Coil	90254A370	000000

Prongless Helical Threaded Insert Removal Tools

Remove prongless inserts without damaging threads or the surface of your material. These tools also back out or adjust inserts that are installed too deep.

Replacement Tips—Replacement tips (sold separately) come with one removal tip, two pins, and two springs.

	Removal Tools				Replacement Tips
	For Thread Size	For Use With		Each		Each
Metric Thread



		M2	Helical Inserts, Screw-Locking Helical Inserts	91049A378	0000000	91049A508	000000

Helical Threaded Insert Installation and Prong Break-Off Tools

L-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.

Handle Style		Each



2-56, M2 × 0.4 mm, M2.5 × 0.45 mm	L-Handle	92450A195	000000

Punch-Style Helical Threaded Insert Prong Break-Off Tools

Break the prong off of installed helical inserts. Place these tools inside the insert and hit the back with a hammer. Once removed, thread in your fastener.

For Thread Size	Handle Style	For Use With		Each
2-56, 3-48, M2, M2.5	Straight	Helical Inserts, Screw-Locking Helical Inserts	1231N11	00000