12-24 Reducers | McMaster-Carr

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DFARS Specialty Metals

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Yes

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Screw-Locking Helical Inserts

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23 Products

About Threaded Inserts

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

Mil.-Spec. Key-Locking Threaded Inserts For Soft Metal

These inserts are manufactured and tested to meet or compare to strict standards adopted by the U.S. military. The keys drive into aluminum and other soft metal for a secure hold that won't slip or rotate, even in vibrating vehicle or aerospace parts. 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.

Thin Wall—Use these inserts near the edge of workpieces or wherever you only have space for a small hole. They're also lighter than standard and extra-thick wall inserts for applications with strict weight limitations.

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.	Drill Bit Size	For Max. Hole Dia.	No. of Locking Keys	Specs. Met		Each		Each
Thin Wall







				18-8 Stainless Steel

				4-40	12-24	0.250"	14 Ga.	0.183"	2	NAS1395C04	93904A211	00000	93904A256	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



	12-24	—	Crank	Threaded	Helical Inserts, Screw-Locking Helical Inserts	1338N24	000000


	12-24	Heli-Coil	Crank	Threaded	Helical Inserts, Screw-Locking Helical Inserts	90261A110	000000

Break Away Key-Locking Threaded Insert Drivers

Image of ProductInUse. Front orientation. Contains Annotated, MultipleImages. Threaded Insert Installation Tools. Break Away Key-Locking Threaded Insert Drivers.

Get the force needed to break off keys and drive them into material. These drivers are the last step to install key-locking inserts. Slide them over the keys and strike the back with a hammer. Their heft makes the blow from your hammer count—no wasted effort. They fit key-locking inserts that meet NAS1394 and NAS1395.

		Each
Standard (UN) Thread







	For Thin-Wall Inserts

	4-40	12-24	Straight	93904A256	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	12-24 Thread × 0.216" Installed Lg. (12 Each) 12-24 Thread × 0.328" Installed Lg. (12 Each) 12-24 Thread × 0.432" Installed Lg. (12 Each) Drill Bit Installation Tool Prong Break-Off Tool Through-Hole Tap	Coarse	15/64"	0.234"	91732A917	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



10-32, 12-24, 12-28, M5 × 0.8 mm	L-Handle	92450A176	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
Standard (UN) Thread



	12-24	Square	Helical Inserts, Screw-Locking Helical Inserts	93060A077	000000

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

	12-24	0.324"	15/64"	0.234"	10	Drill Bit Installation Tool Through-Hole Tap	91732A918	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
10-24, 10-32, 12-24, M5	Straight	Helical Inserts, Screw-Locking Helical Inserts	1231N15	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



	10-24, 10-32, 12-24	Heli-Coil	92955A109	000000


	10-24, 10-32, 12-24, M5	—	92955A316	00000


	For Long Inserts



			10-24, 10-32, 12-24, M5	—	92955A416	00000

Tight-Space Rivet Nuts

Add threads to sheet metal and panels in confined spaces with limited backside clearance. At installation, these compact nuts collapse into themselves and press slightly outward, creating snug-fitting threads half the length of a standard nut but just as strong. With a thin top flange that creates a near-flush fit, they're ideal for light duty fastening in small enclosures or housings.

Install these nuts using a hand- or power-driven rivet nut tool. In thick material, drill or punch a slightly larger hole to ensure the nut body expands uniformly.

Tin Zinc-Plated Steel—Twice as strong as aluminum rivet nuts. The plating resists rust and helps the nut collapse without friction during installation. It's also nontoxic, unlike cadmium plating.

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

	Rivet Nuts											Hand-Driven Tools		Mandrels
							Flange
	Thread Size	Drill Bit Size	For Material Thk.	Body Dia.	Lg.	Installed Lg.	Dia.	Thk.	Pkg. Qty.		Pkg.		Each		Each
Tin Zinc-Plated Steel



		12-24	3/8"	0.030" to 0.090"	0.374"	0.5"	0.245"	0.4"	0.015"	10	98560A567	00000	98590A100	000000	98590A255	000000

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

				12-24	0.216"	1 Ga.	0.228"	MS21209C2-10, NASM21209	10	90296A032	000000	91709A067	000000	91709A434	000000	90261A110	0000000	92955A109	000000


				12-24	0.324"	1 Ga.	0.228"	MS21209C2-15, NASM21209	10	90296A034	00000	91709A067	00000	91709A434	00000	90261A110	000000	92955A109	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		Prong Break-Off Tools		Inserts with Installation Tools
	Thread Size	Installed Lg.	Drill Bit Size	For Max. Hole Dia.	Pkg. Qty.		Pkg.		Each		Each		Each		Each	No. of Inserts Included		Each
Pronged







				18-8 Stainless Steel

				12-24	0.216"	1 Ga.	0.228"	10	91732A021	00000	91709A067	000000	91709A434	000000	90261A110	0000000	92955A109	000000	—	———	0


				12-24	0.324"	1 Ga.	0.228"	10	91732A023	0000	91709A067	00000	91709A434	00000	90261A110	000000	92955A109	00000	10	91732A918	000000
				12-24	0.432"	1 Ga.	0.228"	10	91732A731	0000	91709A067	00000	91709A434	00000	90261A110	000000	92955A109	00000	—	———	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.

		Each
For Pronged Helical Inserts



	10-24, 10-32, 12-24, 12-28, 1/4"-20, 1/4"-28, 1/4"-32, 1/4"-80, 5/16"-18, 5/16"-24, 5/16"-32, 3/8"-16, 3/8"-24, M5, M6, M7, M8, M10	90254A320	000000