1-64 Helicoils | McMaster-Carr

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System of Measurement

Helical Insert Type

Material

For Use In

Installed Length

Drill Bit Size

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For Insert Thread Size

1-64

For Tap Type

Helical

Number of Inserts Included

288

Export Control Classification Number (ECCN)

Thread Direction

Chamfer Type

Tensile Strength

Sold As

For Material Thickness

U.S.–Mexico–Canada Agreement (USMCA) Qualifying

Yes

REACH

Compliant

DFARS Specialty Metals

RoHS

Thread Spacing

For Use On

Handle Style

Profile

Passivation

18 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.	Drill Bit Size	For Max. Hole Dia.	Pkg. Qty.		Pkg.		Each		Each		Each		Each
Pronged







				18-8 Stainless Steel

				1-64	0.073"	46 Ga.	0.081"	10	91732A004	00000	91709A090	000000	91709A683	000000	90261A131	0000000	92955A201	0000000


				1-64	0.110"	46 Ga.	0.081"	10	91732A008	0000	91709A090	00000	91709A683	00000	90261A131	000000	92955A201	000000
				1-64	0.146"	46 Ga.	0.081"	10	91732A011	0000	91709A090	00000	91709A683	00000	90261A131	000000	92955A201	000000


				Prongless







								18-8 Stainless Steel

								1-64	0.073"	46 Ga.	0.081"	5	91990A504	0000	91709A090	00000	91709A683	00000	91049A101	000000	———	0


								1-64	0.110"	46 Ga.	0.081"	5	91990A505	0000	91709A090	00000	91709A683	00000	91049A101	000000	———	0
								1-64	0.146"	46 Ga.	0.081"	5	91990A506	0000	91709A090	00000	91709A683	00000	91049A101	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



			1-64	91049A377	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	Decimal Size Equiv.	Shank Type		Each		Each
High-Speed Steel







				Uncoated

				1-64	1/2"	1 13/16"	UNC	3	46 Ga.	0.081"	Square	91709A090	000000	———	0


				1-64	9/16"	1 7/8"	UNC	3	46 Ga.	0.0810"	Square	———	0	91709A683	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


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
Standard (UN) Thread



	1-64	Heli-Coil	T-Handle	Threaded	Helical Inserts, Screw-Locking Helical Inserts	90261A131	0000000

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

	288	1-64 Thread × 0.11" Installed Lg. (24 Inserts and 24 Screw-Locking Inserts) 2-56 Thread × 0.129" Installed Lg. (24 Inserts and 24 Screw-Locking Inserts) 3-48 Thread × 0.148" Installed Lg. (24 Inserts and 24 Screw-Locking Inserts) 4-40 Thread × 0.168" Installed Lg. (24 Inserts and 24 Screw-Locking Inserts) 6-32 Thread × 0.207" Installed Lg. (24 Inserts and 24 Screw-Locking Inserts) 8-32 Thread × 0.246" Installed Lg. (24 Inserts and 24 Screw-Locking Inserts) Drill Bits Installation Tools Through-Hole Taps	Coarse	5/64" 3/32" 36 Ga. 31 Ga. 26 Ga. 17 Ga.	0.078" 0.094" 0.107" 0.120" 0.147" 0.173"	90285A134	0000000

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.

	Mfr.		Each
For Standard-Length Inserts



	1-64	Heli-Coil	92955A201	0000000

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
Narrow Profile



	1-64, 1-72, M2	Heli-Coil	90254A370	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		Prong Break-Off Tools
	Thread Size	Installed Lg.	Drill Bit Size	For Max. Hole Dia.	Pkg. Qty.		Pkg.		Each		Each		Each		Each
Pronged







				18-8 Stainless Steel

				1-64	0.073"	46 Ga.	0.081"	5	90296A004	00000	91709A090	000000	91709A683	000000	90261A131	0000000	92955A201	0000000


				1-64	0.110"	46 Ga.	0.081"	5	90296A008	0000	91709A090	00000	91709A683	00000	90261A131	000000	92955A201	000000

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
Standard (UN) Thread



	1-64	Straight	Helical Inserts, Screw-Locking Helical Inserts	91049A101	0000000

Replacement Tips

For Thread Size		Each
1-64	91049A202	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
Standard (UN) Thread



		1-64	Helical Inserts, Screw-Locking Helical Inserts	91049A377	0000000	91049A502	000000