4-48 Reducers | McMaster-Carr

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23 Products

Inch-to-Inch Male Hex Thread Adapters

Need to join two female-threaded parts, such as coupling nuts, with dissimilar inch thread sizes? Attach them to these adapters and tighten the exterior hex nut for a secure connection. You can also use these adapters to change the gender of a mating part from female to male, increase or decrease the thread size, or convert the threads from fine to coarse (and vice versa). The smaller adapters act as threaded standoffs, positioning and separating circuit boards and other components in assemblies.

18-8 Stainless Steel—18-8 stainless steel adapters resist corrosion caused by water. They're good for wet and damp environments but will corrode when exposed to salt water and other chloride solutions.

ASTM A582—Adapters that meet ASTM specifications are made from or plated with materials that adhere to specific standards for chemical and physical properties, such as hardness.

			Thread Lg.		Thread Fit		Hex
	Thread Size (A)	Thread Size (B)	(A)	(B)	(A)	(B)	Size	Length	Specs. Met	Tensile Strength, psi	Hardness	Certificate Form	Certificate Type		Each
18-8 Stainless Steel



		2-56	4-48	5/32"	3/16"	Unified Standard Class 2A	Unified Standard Class 2A	3/16"	1/8"	ASTM A582	85,000	Rockwell B80	—	—	95316A379	00000


		4-40	4-48	3/16"	3/16"	Unified Standard Class 2A	Unified Standard Class 2A	1/4"	1/8"	ASTM A582	85,000	Rockwell B80	Digital	Material Certificate with Traceable Lot Number	95316A382	0000
		4-48	6-32	3/16"	1/4"	Unified Standard Class 2A	Unified Standard Class 2A	1/4"	1/8"	ASTM A582	85,000	Rockwell B80	—	—	95316A401	0000
		4-48	6-40	3/16"	1/4"	Unified Standard Class 2A	Unified Standard Class 2A	1/4"	1/8"	ASTM A582	85,000	Rockwell B80	—	Material Certificate with Traceable Lot Number	95316A408	0000

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



	4-48	—	Crank	Threaded	Helical Inserts, Screw-Locking Helical Inserts	1338N15	000000


	4-48	Heli-Coil	Crank	Threaded	Helical Inserts, Screw-Locking Helical Inserts	90261A102	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



4-40, 4-48, 5-40, M3 × 0.5 mm	L-Handle	92450A172	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	1231N12	00000

Inch-to-Inch Male-Female Hex Thread Adapters

Change thread sizes or types, such as fine to coarse threads, on parts without changing gender. These adapters can also be used as standoffs to position components in assemblies and to create space between parts. They have an external hex, so you can tighten them with a wrench.

18-8 Stainless Steel—18-8 stainless steel adapters resist corrosion in wet environments but will corrode when exposed to salt water and chemicals. They may be mildly magnetic.

ASTM A582—Adapters that meet ASTM specifications are made from or plated with materials that adhere to specific standards for chemical and physical properties, such as hardness.

			Thread Lg.		Gender		Thread Fit		Hex
	Thread Size (A)	Thread Size (B)	(A)	(B)	(A)	(B)	(A)	(B)	Size	Length	Specs. Met	Tensile Strength, psi	Hardness		Each
18-8 Stainless Steel



		4-48	4-40	3/16"	7/32"	Male	Female	Unified Standard Class 2A	Unified Standard Class 2B	1/4"	1/2"	ASTM A582	85,000	Rockwell B80	92499A101	00000


		4-48	6-32	3/16"	1/4"	Male	Female	Unified Standard Class 2A	Unified Standard Class 2B	1/4"	1/2"	ASTM A582	85,000	Rockwell B80	92499A102	0000

Inch-to-Inch Female Hex Thread Adapters

Connect two differently sized male-threaded parts, such as threaded rods, and tighten with a standard wrench. The threads on these adapters have various sizes and spacing, so you can increase or decrease thread size or adapt from coarse to fine threading. You can also use them to change the gender of a connection from male to female. Small adapters can work as threaded standoffs, which position and separate circuit boards and other components in assemblies.

18-8 Stainless Steel—18-8 stainless steel adapters withstand wet environments but will corrode when exposed to salt water and other chloride solutions.

316 Stainless Steel—316 stainless steel adapters are ideal in wet environments and will not corrode when exposed to salt water or harsh chemicals.

ASTM A276 and ASTM A582—Adapters that meet ASTM specifications are made from or plated with materials that adhere to specific standards for chemical and physical properties, such as hardness.

			Thread Lg.		Thread Fit		Hex						Each
	Thread Size (A)	Thread Size (B)	(A)	(B)	(A)	(B)	Size	Length	Specs. Met	Tensile Strength, psi	Hardness		1-9	10-Up
18-8 Stainless Steel



		4-40	4-48	1/8"	1/8"	Unified Standard Class 2B	Unified Standard Class 2B	5/16"	7/16"	ASTM A582	85,000	Rockwell B80	91072A101	00000	00000


		4-48	6-32	9/64"	9/64"	Unified Standard Class 2B	Unified Standard Class 2B	5/16"	1/2"	ASTM A582	85,000	Rockwell B80	91072A103	0000	0000


		316 Stainless Steel



				4-48	6-32	9/64"	9/64"	Unified Standard Class 2B	Unified Standard Class 2B	5/16"	1/2"	ASTM A276	75,000	Rockwell B83	91072A191	0000	0000

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

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

				4-48	0.112"	31 Ga.	0.120"	MS124671	10	91732A005	00000	91709A057	000000	91709A410	000000	90261A102	0000000	92955A103	0000000


				4-48	0.168"	31 Ga.	0.120"	MS124711	10	91732A007	0000	91709A057	00000	91709A410	00000	90261A102	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

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

				4-48	0.112"	31 Ga.	0.120"	MS21209F0410, NASM21209	10	90296A016	00000	91709A057	000000	91709A410	000000	90261A102	0000000	92955A103	0000000


				4-48	0.168"	31 Ga.	0.120"	MS21209F0415, NASM21209	10	90296A018	0000	91709A057	00000	91709A410	00000	90261A102	000000	92955A103	000000