M3 Helicoils | McMaster-Carr

Filter by

System of Measurement

Helical Insert Type

Installed Length

Material

Thread Pitch

Thread Type

For Use In

For Tap Type

For Insert Thread Size

Drill Bit Size

Specifications Met

Number of Inserts Included

Thread Spacing

Coarse

Thread Direction

Left Hand

Right Hand

DFARS Specialty Metals

RoHS

REACH

For Insert Thread Pitch

0.5 mm

Military Specification

MIL-I-8846

Tensile Strength

200,000 psi

Export Control Classification Number (ECCN)

Passivation

Chamfer Type

Sold As

Profile

44 Products

About Threaded Inserts

Choose the right threaded insert for your application and learn how to install it securely.

Helical Threaded Inserts


Pronged	Prongless

Restore, reinforce, or create metal threads. 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. Easy-start installation tools compress the diameter of your insert so it fits easily into a tapped hole. These tools are the best choice for preventing misaligned or damaged threads—just make sure you have space to turn the crank.

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.

Nickel—More resistant to acids and salt water than stainless steel inserts.

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







				18-8 Stainless Steel

				M3 x 0.5 mm	3	3.2	3.2	DIN 8140, SAE MA3279-102	10	000000000	00000	000000000	000000	000000000	000000	000000000	0000000	000000000	0000000	10	000000000	0000000


				M3 x 0.5 mm	4.5	3.2	3.2	DIN 8140, SAE MA3279-152	10	000000000	0000	000000000	00000	000000000	00000	000000000	000000	000000000	000000	10	000000000	000000
				M3 x 0.5 mm	6	3.2	3.2	DIN 8140, SAE MA3279-202	10	000000000	0000	000000000	00000	000000000	00000	000000000	000000	000000000	000000	10	000000000	000000
				M3 x 0.5 mm	7.5	3.2	3.2	DIN 8140, SAE MA3279-252	10	000000000	0000	000000000	00000	000000000	00000	000000000	000000	000000000	000000	—	———	0
				M3 x 0.5 mm	9	3.15	3.15	SAE MA3279-302	10	000000000	0000	000000000	00000	000000000	00000	000000000	000000	000000000	000000	—	———	0




						Nickel

						M3 x 0.5 mm	3	3.2	3.2	—	1	000000000	0000	000000000	00000	000000000	00000	000000000	000000	000000000	000000	—	———	0


						M3 x 0.5 mm	6	3.2	3.2	—	1	000000000	0000	000000000	00000	000000000	00000	000000000	000000	000000000	000000	—	———	0


						Prongless







										18-8 Stainless Steel

										M3 x 0.5 mm	3	3.2	3.2	NA0276M3-10	10	000000000	0000	000000000	00000	000000000	00000	000000000	000000	———	0	—	———	0


										M3 x 0.5 mm	4.5	3.2	3.2	NA0276M3-15	10	000000000	0000	000000000	00000	000000000	00000	000000000	000000	———	0	—	———	0
										M3 x 0.5 mm	6	3.2	3.2	NA0276M3-20	10	000000000	0000	000000000	00000	000000000	00000	000000000	000000	———	0	—	———	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



	3-48, 3-56, 4-40, 4-48, 5-40, 5-44, 6-32, 6-40, 8-32, 8-36, 8-40, M2.5, M3, M3.5, M4	000000000	000000


	For Prongless Helical Inserts



			M3	000000000	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

				M3	11/16"	2"	Metric	3	3.2	0.1259"	Square	000000000	000000	000000000	000000

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.

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

				M3 x 0.5 mm	3	3.2	3.2	5	000000000	00000	000000000	000000	000000000	000000	000000000	0000000	000000000	0000000


				M3 x 0.5 mm	4.5	3.2	3.2	5	000000000	0000	000000000	00000	000000000	00000	000000000	000000	000000000	000000
				M3 x 0.5 mm	6	3.2	3.2	5	000000000	0000	000000000	00000	000000000	00000	000000000	000000	000000000	000000

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


Crank 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



	M3 × 0.5 mm	—	Crank	Threaded	Helical Inserts, Screw-Locking Helical Inserts	0000000	000000


	M3 × 0.5 mm	Heli-Coil	Crank	Threaded	Helical Inserts, Screw-Locking Helical Inserts	000000000	000000

Screw-Locking Helical Threaded Inserts


Pronged	Prongless

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 automobile parts and other machinery that shakes and rattles. Also known as Heli-Coil inserts.

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

				M3 x 0.5 mm	3	3.2	3.2	DIN 8140, SAE MA3329-102	10	000000000	000000	000000000	000000	000000000	000000	000000000	0000000	000000000	0000000


				M3 x 0.5 mm	4.5	3.2	3.2	DIN 8140, SAE MA3329-152	10	000000000	00000	000000000	00000	000000000	00000	000000000	000000	000000000	000000
				M3 x 0.5 mm	6	3.2	3.2	DIN 8140, SAE MA3329-202	10	000000000	00000	000000000	00000	000000000	00000	000000000	000000	000000000	000000
				M3 x 0.5 mm	7.5	3.2	3.2	DIN 8140, SAE MA3329-252	1	000000000	0000	000000000	00000	000000000	00000	000000000	000000	000000000	000000


				Prongless







								18-8 Stainless Steel

								M3 x 0.5 mm	3	3.2	3.2	NA0276M3-L10	10	000000000	0000	000000000	00000	000000000	00000	000000000	000000	———	0


								M3 x 0.5 mm	4.5	3.2	3.2	NA0276M3-L15	10	000000000	0000	000000000	00000	000000000	00000	000000000	000000	———	0
								M3 x 0.5 mm	6	3.2	3.2	DIN 8140, NA0276M3-L20	10	000000000	0000	000000000	00000	000000000	00000	000000000	000000	———	0

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	—	000000000	000000


	4-40, 4-48, 5-40, 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, M3, M3.5, M4, M5, M6, M7, M8, M9, M10, M12, M13, M14	—	000000000	00000


	Narrow Profile



			3-48, 3-56, 4-40, 4-48, 5-40, 5-44, 6-32, 6-40, 8-32, 8-36, 8-40, M2.5, M3, M3.5, M4	Heli-Coil	000000000	00000

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



	M3, M3.5	Heli-Coil	000000000	0000000


	For Long Inserts



			4-40, 4-48, 5-40, M3	—	000000000	00000

Easy-Start Prongless Helical Threaded Insert Installation Tools

Install prongless (tangless) helical inserts more quickly and consistently than with standard tools. These tools compress your insert’s diameter and align each coil with the thread pitch, guiding it straight 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 an insert onto these tools and drive them a quarter- to half-turn below the material’s surface. Also known as prewinders.

	Handle Style	For Use With		Each
Metric Thread



	M3 × 0.5 mm	Crank	Helical Inserts, Screw-Locking Helical Inserts	000000000	0000000

Replacement Tips

For Thread Size		Each
M3	000000000	000000

Helical Threaded Insert Assortments with Installation Tools

Repair damaged threads or create new ones. These convenient assortments include helical inserts, an installation tool for each thread size, a drill bit, and a tap. The inserts are also known as Heli-Coil inserts.

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.

	Drill Bit Size	For Max. Hole Dia.		Each
Pronged







	18-8 Stainless Steel

	36	Drill Bit Installation Tool M3×0.5 mm Thread × 3 mm Installed Lg. (12 Each) M3×0.5 mm Thread × 4.5 mm Installed Lg. (12 Each) M3×0.5 mm Thread × 6 mm Installed Lg. (12 Each) Through-Hole Tap	Coarse	1/8"	0.125"	000000000	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.

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

	M3 x 0.5 mm	3	3.15	0.125"	10	Drill Bit Installation Tool Through-Hole Tap	000000000	0000000


	M3 x 0.5 mm	4.5	3.15	0.125"	10	Drill Bit Installation Tool Through-Hole Tap	000000000	000000
	M3 x 0.5 mm	6	3.15	0.125"	10	Drill Bit Installation Tool Through-Hole Tap	000000000	000000

Seize-Resistant Helical Threaded Inserts

Pronged

Install and remove screws repeatedly without sticking or binding. These inserts have a dry-film lubricant on their surface for smooth installation. They're ideal for parts that require frequent disassembly for inspection or repair. Also known as Heli-Coil inserts.

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.

Dry-Film-Lubricated 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







				Dry-Film-Lubricated 18-8 Stainless Steel

				M3 x 0.5 mm	3	3.2	3.2	DIN 8140, SAE MA3280-102, MIL-I-8846	1	000000000	00000	000000000	000000	000000000	000000	000000000	0000000	000000000	0000000


				M3 x 0.5 mm	4.5	3.2	3.2	DIN 8140, SAE MA3280-152, MIL-I-8846	1	000000000	0000	000000000	00000	000000000	00000	000000000	000000	000000000	000000
				M3 x 0.5 mm	6	3.2	3.2	DIN 8140, SAE MA3280-202, MIL-I-8846	1	000000000	0000	000000000	00000	000000000	00000	000000000	000000	000000000	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



		M3	Helical Inserts, Screw-Locking Helical Inserts	000000000	0000000	000000000	000000

Seize-Resistant Helical Threaded Inserts for Dissimilar Metals

Skip the primer. These inserts are coated to resist galvanic corrosion when used with aluminum or magnesium. The coating also prevents the screw from sticking or binding during installation. Also known as Heli-Coil inserts.

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.

Dry-Film-Lubricated 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







				Dry-Film-Lubricated 18-8 Stainless Steel

				M3 x 0.5 mm	4.5	3.2	3.2	DIN 8140	1	000000000	00000	000000000	000000	000000000	000000	000000000	0000000	000000000	0000000


				M3 x 0.5 mm	6	3.2	3.2	DIN 8140	1	000000000	0000	000000000	00000	000000000	00000	000000000	000000	000000000	000000

Helical Threaded Insert Installation Tools

No 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.

Square Shank—These tools don’t have a handle. Attach them to a tap wrench to turn.

	Shank Type	For Use With		Each
Metric Thread



	M3 × 0.5 mm	Square	Helical Inserts, Screw-Locking Helical Inserts	000000000	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
4-40, 4-48, 5-40, M3	Straight	Helical Inserts, Screw-Locking Helical Inserts	0000000	00000