5-40 Threaded Inserts | McMaster-Carr

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24 Products

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







				18-8 Stainless Steel

				5-40	0.125"	29 Ga.	0.136"	MS122077	10	91732A009	00000	91709A061	000000	91709A413	000000	90261A104	0000000	92955A103	0000000


				5-40	0.188"	29 Ga.	0.136"	MS122117	10	91732A010	0000	91709A061	00000	91709A413	00000	90261A104	000000	92955A103	000000
				5-40	0.250"	29 Ga.	0.136"	MS122157	10	91732A704	0000	91709A061	00000	91709A413	00000	90261A104	000000	92955A103	000000

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



	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	90254A310	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



	4-40, 4-48, 5-40	Heli-Coil	92955A103	0000000


	4-40, 4-48, 5-40, M3	—	92955A313	00000


	For Long Inserts



			4-40, 4-48, 5-40, M3	—	92955A413	00000

Tapered Heat-Set Threaded Inserts For Plastic

Tapered at one end, these inserts are easier to align in a hole during installation than straight inserts. Use a drill bit to create a straight hole, then taper the top half. Once installed, heat the insert with a soldering tip to melt the surrounding plastic.

Brass—Conductive and nonmagnetic, these inserts are useful for electrical applications. They resist moisture but aren't as strong as steel inserts.

18-8 Stainless Steel—The choice for wet and outdoor environments, these inserts resist rust and mild chemicals. Since they’re lead-free, they can be safely recycled.

	Installed Lg.	Drill Bit Size	For Max. Hole Dia.	For Hole Taper Angle	Specs. Met	Pkg. Qty.		Pkg.
Brass



	5-40	0.150"	8 Ga.	0.199"	8°	ASTM B16	25	93365A201	000000


	5-40	0.250"	13 Ga.	0.185"	8°	ASTM B16	25	93365A202	00000


	18-8 Stainless Steel



			5-40	0.150"	8 Ga.	0.199"	8°	ASTM A582	25	97163A201	00000


			5-40	0.250"	13 Ga.	0.185"	8°	ASTM A582	25	97163A202	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


	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, 3/8"-16, M3, M3.5, M4, M5, M6, M7, M8, M9, M10	—	90254A112	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	90254A310	00000

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







				18-8 Stainless Steel

				5-40	0.125"	29 Ga.	0.136"	NASM21209, MS21209C0510	10	90296A020	00000	91709A061	000000	91709A413	000000	90261A104	0000000	92955A103	0000000


				5-40	0.188"	29 Ga.	0.136"	NASM21209, MS21209C0515	10	90296A022	0000	91709A061	00000	91709A413	00000	90261A104	000000	92955A103	000000
				5-40	0.250"	29 Ga.	0.136"	NASM21209, MS21209C0520	5	90296A023	0000	91709A061	00000	91709A413	00000	90261A104	000000	92955A103	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
Standard (UN) Thread



	5-40	—	Crank	Threaded	Helical Inserts, Screw-Locking Helical Inserts	1338N16	000000


	5-40	Heli-Coil	Crank	Threaded	Helical Inserts, Screw-Locking Helical Inserts	90261A104	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	5-40 Thread × 0.188" Installed Lg. (12 Each) 5-40 Thread × 1/4" Installed Lg. (12 Each) 5-40 Thread × 1/8" Installed Lg. (12 Each) Drill Bit Installation Tool Prong Break-Off Tool Through-Hole Tap	Coarse	29 Ga.	0.136"	91732A903	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	Ht.	Threading	Thread Dp.	For Hole Dia.	Hex Key Size		Each
Alloy Steel



	5-40	0.18"	0.2"	Partially Threaded	0.1"	0.202"	1/8"	92066A006	00000

Stainless Steel Socket Nuts

These nuts are chemical resistant and may be mildly magnetic. Also known as Allen nuts, use them 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.

	OD	Ht.	Threading	Thread Dp.	For Hole Dia.	Hex Key Size		Each
18-8 Stainless Steel



	5-40	0.19"	0.21"	Partially Threaded	0.1"	0.202"	1/8"	90372A101	00000

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	1231N12	00000