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Inch-to-Metric Male-Female Hex Thread Adapters


Change inch threads to metric with these adapters, or swap metric threads for inch. An external hex lets you tighten or loosen them with a wrench. You can also use them to increase or reduce your thread size, or to create space between parts in an assembly.
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.
Black oxide steel adapters have a black finish that won’t chip or rub off. They will not rust in dry or indoor environments, but will corrode if used outdoors.
Zinc-plated steel adapters should be used in mostly dry environments. The zinc plating offers temporary rust protection, but once it wears away the steel will rust.
At one third the weight of steel, aluminum adapters are the lightest option. They will not rust in damp or humid environments, but they will corrode if left in water.
18-8 stainless steel adapters can be used in wet environments, but chemicals or salt water will cause staining and rust spots.
For technical drawings and 3-D models, click on a part number.
Thread Size | Thread Lg. | Gender | Thread Fit | Hex | ||||||||||||
---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
(A) | Pitch (A), mm | (B) | Pitch (B), mm | (A) | (B) | (A) | (B) | (A) | (B) | Size | Lg. | Specifications Met | Tensile Strength, psi | Hardness | Each | |
Black-Oxide Steel | ||||||||||||||||
Inch to Metric | ||||||||||||||||
4-40 | __ | M2.5 | 0.45 | 3/16" | 4.8mm | Male | Female | Class 2A | Class 6H | 3/16" | 1" | ASTM A108 | 78,000 | Rockwell B85 | 000000000 | 00000 |
6-32 | __ | M2.5 | 0.45 | 1/4" | 4.8mm | Male | Female | Class 2A | Class 6H | 3/16" | 1" | ASTM A108 | 78,000 | Rockwell B85 | 000000000 | 0000 |
8-32 | __ | M2.5 | 0.45 | 3/8" | 4.8mm | Male | Female | Class 2A | Class 6H | 1/4" | 1" | ASTM A108 | 78,000 | Rockwell B85 | 000000000 | 0000 |
Metric to Inch | ||||||||||||||||
M2.5 | 0.45 | 4-40 | __ | 4mm | 1/4" | Male | Female | Class 6g | Class 2B | 4.5mm | 25mm | ASTM A108 | 78,000 | Rockwell B85 | 000000000 | 0000 |
M2.5 | 0.45 | 6-32 | __ | 4mm | 3/8" | Male | Female | Class 6g | Class 2B | 6mm | 25mm | ASTM A108 | 78,000 | Rockwell B85 | 000000000 | 0000 |
M2.5 | 0.45 | 8-32 | __ | 4mm | 7/16" | Male | Female | Class 6g | Class 2B | 6mm | 25mm | ASTM A108 | 78,000 | Rockwell B85 | 000000000 | 0000 |
Zinc-Plated Steel | ||||||||||||||||
Inch to Metric | ||||||||||||||||
2-56 | __ | M2.5 | 0.45 | 5/32" | 4.8mm | Male | Female | Class 2A | Class 6H | 3/16" | 1" | ASTM A108, ASTM B633 | 78,000 | Rockwell B85 | 000000000 | 0000 |
4-40 | __ | M2.5 | 0.45 | 3/16" | 4.8mm | Male | Female | Class 2A | Class 6H | 3/16" | 1" | ASTM A108, ASTM B633 | 78,000 | Rockwell B85 | 000000000 | 0000 |
6-32 | __ | M2.5 | 0.45 | 1/4" | 4.8mm | Male | Female | Class 2A | Class 6H | 3/16" | 1" | ASTM A108, ASTM B633 | 78,000 | Rockwell B85 | 000000000 | 0000 |
8-32 | __ | M2.5 | 0.45 | 3/8" | 4.8mm | Male | Female | Class 2A | Class 6H | 1/4" | 1" | ASTM A108, ASTM B633 | 78,000 | Rockwell B85 | 000000000 | 0000 |
Metric to Inch | ||||||||||||||||
M2.5 | 0.45 | 2-56 | __ | 4mm | 3/16" | Male | Female | Class 6g | Class 2B | 4.5mm | 25mm | ASTM A108, ASTM B633 | 78,000 | Rockwell B85 | 000000000 | 0000 |
M2.5 | 0.45 | 4-40 | __ | 4mm | 1/4" | Male | Female | Class 6g | Class 2B | 4.5mm | 25mm | ASTM A108, ASTM B633 | 78,000 | Rockwell B85 | 000000000 | 0000 |
M2.5 | 0.45 | 6-32 | __ | 4mm | 3/8" | Male | Female | Class 6g | Class 2B | 6mm | 25mm | ASTM A108, ASTM B633 | 78,000 | Rockwell B85 | 000000000 | 0000 |
M2.5 | 0.45 | 8-32 | __ | 4mm | 7/16" | Male | Female | Class 6g | Class 2B | 6mm | 25mm | ASTM A108, ASTM B633 | 78,000 | Rockwell B85 | 000000000 | 0000 |
Aluminum | ||||||||||||||||
Inch to Metric | ||||||||||||||||
2-56 | __ | M2.5 | 0.45 | 5/32" | 4.8mm | Male | Female | Class 2A | Class 6H | 3/16" | 1" | __ | 45,000 | Rockwell B56 | 000000000 | 0000 |
4-40 | __ | M2.5 | 0.45 | 3/16" | 4.8mm | Male | Female | Class 2A | Class 6H | 3/16" | 1" | __ | 45,000 | Rockwell B56 | 000000000 | 0000 |
6-32 | __ | M2.5 | 0.45 | 1/4" | 4.8mm | Male | Female | Class 2A | Class 6H | 3/16" | 1" | __ | 45,000 | Rockwell B56 | 000000000 | 0000 |
8-32 | __ | M2.5 | 0.45 | 3/8" | 4.8mm | Male | Female | Class 2A | Class 6H | 1/4" | 1" | __ | 45,000 | Rockwell B56 | 000000000 | 0000 |
Metric to Inch | ||||||||||||||||
M2.5 | 0.45 | 4-40 | __ | 4mm | 1/4" | Male | Female | Class 6g | Class 2B | 4.5mm | 25mm | __ | 45,000 | Rockwell B56 | 000000000 | 0000 |
M2.5 | 0.45 | 6-32 | __ | 4mm | 3/8" | Male | Female | Class 6g | Class 2B | 6mm | 25mm | __ | 45,000 | Rockwell B56 | 000000000 | 0000 |
M2.5 | 0.45 | 8-32 | __ | 4mm | 7/16" | Male | Female | Class 6g | Class 2B | 6mm | 25mm | __ | 45,000 | Rockwell B56 | 000000000 | 0000 |
18-8 Stainless Steel | ||||||||||||||||
Inch to Metric | ||||||||||||||||
2-56 | __ | M2.5 | 0.45 | 5/32" | 4.8mm | Male | Female | Class 2A | Class 6H | 3/16" | 1" | ASTM A582 | 85,000 | Rockwell B80 | 000000000 | 0000 |
4-40 | __ | M2.5 | 0.45 | 3/16" | 4.8mm | Male | Female | Class 2A | Class 6H | 3/16" | 1" | ASTM A582 | 85,000 | Rockwell B80 | 000000000 | 0000 |
6-32 | __ | M2.5 | 0.45 | 1/4" | 4.8mm | Male | Female | Class 2A | Class 6H | 3/16" | 1" | ASTM A582 | 85,000 | Rockwell B80 | 000000000 | 0000 |
8-32 | __ | M2.5 | 0.45 | 3/8" | 4.8mm | Male | Female | Class 2A | Class 6H | 1/4" | 1" | ASTM A582 | 85,000 | Rockwell B80 | 000000000 | 0000 |
Metric to Inch | ||||||||||||||||
M2.5 | 0.45 | 2-56 | __ | 4mm | 3/16" | Male | Female | Class 6g | Class 2B | 4.5mm | 25mm | ASTM A582 | 85,000 | Rockwell B80 | 000000000 | 0000 |
M2.5 | 0.45 | 4-40 | __ | 4mm | 1/4" | Male | Female | Class 6g | Class 2B | 4.5mm | 25mm | ASTM A582 | 85,000 | Rockwell B80 | 000000000 | 0000 |
M2.5 | 0.45 | 6-32 | __ | 4mm | 3/8" | Male | Female | Class 6g | Class 2B | 6mm | 25mm | ASTM A582 | 85,000 | Rockwell B80 | 000000000 | 0000 |
M2.5 | 0.45 | 8-32 | __ | 4mm | 7/16" | Male | Female | Class 6g | Class 2B | 6mm | 25mm | ASTM A582 | 85,000 | Rockwell B80 | 000000000 | 0000 |
Metric-to-Metric Male-Female Hex Thread Adapters


In addition to joining male- and female-threaded parts, these adapters can increase or decrease metric thread sizes and change the thread pitch. You can also use the smaller adapters as threaded standoffs, positioning and separating circuit boards and other components in assemblies.
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.
Choose black-oxide steel adapters to match the aesthetics of your system or for their mild corrosion resistance. The finish won't chip or rub off. They resist rust in indoor and dry environments, but avoid using them in corrosive environments.
Zinc-plated steel adapters are a good option in dry environments. The zinc plating prevents the steel from corroding until the plating wears away.
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.
316 stainless steel adapters have the best corrosion resistance. They stand up to wet environments, just like 18-8 stainless steel adapters, but unlike 18-8 stainless steel adapters, they resist corrosion caused by salt water and harsh chemicals.
At about a third of the weight of steel adapters, aluminum adapters are the lightest we offer. They resist corrosion in wet environments.
For technical drawings and 3-D models, click on a part number.
Thread Size | Thread Lg. | Gender | Thread FIt | Hex | ||||||||||||
---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
(A) | Pitch (A), mm | (B) | Pitch (B), mm | (A), mm | (B), mm | (A) | (B) | (A) | (B) | Size, mm | Lg., mm | Specifications Met | Tensile Strength, psi | Hardness | Each | |
Black-Oxide Steel | ||||||||||||||||
M2.5 | 0.45 | M3 | 0.5 | 4 | 6.4 | Male | Female | Class 6g | Class 6H | 4.5 | 25 | ASTM A108 | 75,000 | Rockwell B65 | 000000000 | 00000 |
M2.5 | 0.45 | M4 | 0.7 | 4 | 11.1 | Male | Female | Class 6g | Class 6H | 6 | 25 | ASTM A108 | 75,000 | Rockwell B65 | 000000000 | 0000 |
M3 | 0.5 | M2.5 | 0.45 | 4.8 | 4.8 | Male | Female | Class 6g | Class 6H | 4.5 | 25 | ASTM A108 | 75,000 | Rockwell B65 | 000000000 | 0000 |
M4 | 0.7 | M2.5 | 0.45 | 9.5 | 4.8 | Male | Female | Class 6g | Class 6H | 6 | 25 | ASTM A108 | 75,000 | Rockwell B65 | 000000000 | 0000 |
Zinc-Plated Steel | ||||||||||||||||
M2.5 | 0.45 | M4 | 0.7 | 4 | 11.1 | Male | Female | Class 6g | Class 6H | 6 | 25 | ASTM A108, ASTM B633 | 75,000 | Rockwell B65 | 000000000 | 0000 |
M3 | 0.5 | M2.5 | 0.45 | 4.8 | 4.8 | Male | Female | Class 6g | Class 6H | 4.5 | 25 | ASTM A108, ASTM B633 | 75,000 | Rockwell B65 | 000000000 | 0000 |
M4 | 0.7 | M2.5 | 0.45 | 9.5 | 4.8 | Male | Female | Class 6g | Class 6H | 6 | 25 | ASTM A108, ASTM B633 | 75,000 | Rockwell B65 | 000000000 | 0000 |
18-8 Stainless Steel | ||||||||||||||||
M2.5 | 0.45 | M3 | 0.5 | 4 | 6.4 | Male | Female | Class 6g | Class 6H | 4.5 | 25 | ASTM A582 | 85,000 | Rockwell B80 | 000000000 | 0000 |
M2.5 | 0.45 | M4 | 0.7 | 4 | 11.1 | Male | Female | Class 6g | Class 6H | 6 | 25 | ASTM A582 | 85,000 | Rockwell B80 | 000000000 | 0000 |
M3 | 0.35 | M2.5 | 0.45 | 7.5 | 3 | Male | Female | Class 6g | Class 6H | 10 | 12.7 | ASTM A582 | 85,000 | Rockwell B80 | 000000000 | 0000 |
M3 | 0.5 | M2.5 | 0.45 | 4.8 | 4.8 | Male | Female | Class 6g | Class 6H | 4.5 | 25 | ASTM A582 | 85,000 | Rockwell B80 | 000000000 | 0000 |
M4 | 0.7 | M2.5 | 0.45 | 9.5 | 4.8 | Male | Female | Class 6g | Class 6H | 6 | 25 | ASTM A582 | 85,000 | Rockwell B80 | 000000000 | 0000 |
316 Stainless Steel | ||||||||||||||||
M3 | 0.5 | M2.5 | 0.45 | 7.5 | 3 | Male | Female | Class 6g | Class 6H | 10 | 12.7 | ASTM A276 | 75,000 | Rockwell B83 | 000000000 | 0000 |
Aluminum | ||||||||||||||||
M2.5 | 0.45 | M3 | 0.5 | 4 | 6.4 | Male | Female | Class 6g | Class 6H | 4.5 | 25 | __ | 45,000 | Rockwell B56 | 000000000 | 0000 |
M2.5 | 0.45 | M4 | 0.7 | 4 | 11.1 | Male | Female | Class 6g | Class 6H | 6 | 25 | __ | 45,000 | Rockwell B56 | 000000000 | 0000 |
M3 | 0.5 | M2.5 | 0.45 | 4.8 | 4.8 | Male | Female | Class 6g | Class 6H | 4.5 | 25 | __ | 45,000 | Rockwell B56 | 000000000 | 0000 |
M4 | 0.7 | M2.5 | 0.45 | 9.5 | 4.8 | Male | Female | Class 6g | Class 6H | 6 | 25 | __ | 45,000 | Rockwell B56 | 000000000 | 0000 |
Inch-to-Metric Male Hex Thread Adapters


One side inch, one side metric, and a hex in the middle—these handy fasteners connect two female-threaded parts, such as coupling nuts, adapting from inch threads to metric. Tighten with a standard wrench.
You can also use these adapters to change the gender of a mating part or increase or decrease its thread size. The small sizes work as standoffs, positioning and separating circuit boards and other components in assemblies.
Choose black-oxide steel adapters to match the aesthetics of your system or for their mild corrosion resistance. The finish won't chip or rub off. They resist rust in indoor and dry environments, but avoid using them in corrosive environments.
Zinc-plated steel adapters are a good option in dry environments. The zinc plating prevents the steel from corroding until the plating wears away.
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.
At about a third of the weight of steel adapters, aluminum adapters are the lightest we offer. They resist corrosion in wet environments.
For technical drawings and 3-D models, click on a part number.
Thread Size | Thread Lg. | Thread Fit | Hex | ||||||||||
---|---|---|---|---|---|---|---|---|---|---|---|---|---|
(A) | (B) | Pitch (B), mm | (A) | (B), mm | (A) | (B) | Size | Lg. | Specifications Met | Tensile Strength, psi | Hardness | Each | |
Black-Oxide Steel | |||||||||||||
4-40 | M2.5 | 0.45 | 3/16" | 4 | Class 2A | Class 6g | 3/16" | 1/4" | ASTM A108 | 78,000 | Rockwell B85 | 000000000 | 00000 |
6-32 | M2.5 | 0.45 | 1/4" | 4 | Class 2A | Class 6g | 3/16" | 1/4" | ASTM A108 | 78,000 | Rockwell B85 | 000000000 | 0000 |
8-32 | M2.5 | 0.45 | 3/8" | 4 | Class 2A | Class 6g | 1/4" | 1/4" | ASTM A108 | 78,000 | Rockwell B85 | 000000000 | 0000 |
Zinc-Plated Steel | |||||||||||||
2-56 | M2.5 | 0.45 | 5/32" | 4 | Class 2A | Class 6g | 3/16" | 1/4" | ASTM A108, ASTM B633 | 78,000 | Rockwell B85 | 000000000 | 0000 |
4-40 | M2.5 | 0.45 | 3/16" | 4 | Class 2A | Class 6g | 3/16" | 1/4" | ASTM A108, ASTM B633 | 78,000 | Rockwell B85 | 000000000 | 0000 |
6-32 | M2.5 | 0.45 | 1/4" | 4 | Class 2A | Class 6g | 3/16" | 1/4" | ASTM A108, ASTM B633 | 78,000 | Rockwell B85 | 000000000 | 0000 |
8-32 | M2.5 | 0.45 | 3/8" | 4 | Class 2A | Class 6g | 1/4" | 1/4" | ASTM A108, ASTM B633 | 78,000 | Rockwell B85 | 000000000 | 0000 |
18-8 Stainless Steel | |||||||||||||
2-56 | M2.5 | 0.45 | 5/32" | 4 | Class 2A | Class 6g | 3/16" | 1/4" | ASTM A582 | 85,000 | Rockwell B80 | 000000000 | 0000 |
4-40 | M2.5 | 0.45 | 3/16" | 4 | Class 2A | Class 6g | 3/16" | 1/4" | ASTM A582 | 85,000 | Rockwell B80 | 000000000 | 0000 |
6-32 | M2.5 | 0.45 | 1/4" | 4 | Class 2A | Class 6g | 3/16" | 1/4" | ASTM A582 | 85,000 | Rockwell B80 | 000000000 | 0000 |
8-32 | M2.5 | 0.45 | 3/8" | 4 | Class 2A | Class 6g | 1/4" | 1/4" | ASTM A582 | 85,000 | Rockwell B80 | 000000000 | 0000 |
Aluminum | |||||||||||||
2-56 | M2.5 | 0.45 | 5/32" | 4 | Class 2A | Class 6g | 3/16" | 1/4" | __ | 45,000 | Rockwell B56 | 000000000 | 0000 |
4-40 | M2.5 | 0.45 | 3/16" | 4 | Class 2A | Class 6g | 3/16" | 1/4" | __ | 45,000 | Rockwell B56 | 000000000 | 0000 |
6-32 | M2.5 | 0.45 | 1/4" | 4 | Class 2A | Class 6g | 3/16" | 1/4" | __ | 45,000 | Rockwell B56 | 000000000 | 0000 |
8-32 | M2.5 | 0.45 | 3/8" | 4 | Class 2A | Class 6g | 1/4" | 1/4" | __ | 45,000 | Rockwell B56 | 000000000 | 0000 |
Metric-to-Metric Male Hex Thread Adapters


Twist these adapters onto female metric threads to change pitch or switch thread sizes. They can also be used as standoffs to make space between parts. Tighten or loosen with a wrench.
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.
Black oxide steel adapters have a black finish that won’t chip or rub off. They will not rust in dry or indoor environments, but will corrode if used outdoors.
Zinc-plated steel adapters should be used in mostly dry environments. The zinc plating offers temporary rust protection, but once it wears away the steel will rust.
At one third the weight of steel, aluminum adapters are the lightest option. They will not rust in damp or humid environments, but they will corrode if left in water.
18-8 stainless steel adapters can be used in wet environments, but chemicals or salt water will cause staining and rust spots.
For areas exposed to salt water or chemicals, 316 stainless steel adapters are the best choice. Only harsh chemicals, such as hydrochloric acid, will cause them to corrode.
Thread Size | Thread Lg. | Thread Fit | Hex | |||||||||||
---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
(A) | Pitch (A), mm | (B) | Pitch (B), mm | (A), mm | (B), mm | (A) | (B) | Size, mm | Lg., mm | Tensile Strength, psi | Hardness | Specifications Met | Each | |
Black-Oxide Steel | ||||||||||||||
M2.5 | 0.45 | M3 | 0.5 | 4 | 4.8 | Class 6g | Class 6g | 4.5 | 6.35 | 75,000 | Rockwell B65 | ASTM A108 | 000000000 | 00000 |
M2.5 | 0.45 | M4 | 0.7 | 4 | 9.5 | Class 6g | Class 6g | 6 | 6.35 | 75,000 | Rockwell B65 | ASTM A108 | 000000000 | 0000 |
Zinc-Plated Steel | ||||||||||||||
M2.5 | 0.45 | M3 | 0.5 | 4 | 4.8 | Class 6g | Class 6g | 4.5 | 6.35 | 75,000 | Rockwell B65 | ASTM A108, ASTM B633 | 000000000 | 0000 |
M2.5 | 0.45 | M3.5 | 0.6 | 4 | 6.4 | Class 6g | Class 6g | 6 | 6.35 | 75,000 | Rockwell B65 | ASTM A108, ASTM B633 | 000000000 | 0000 |
M2.5 | 0.45 | M4 | 0.7 | 4 | 9.5 | Class 6g | Class 6g | 6 | 6.35 | 75,000 | Rockwell B65 | ASTM A108, ASTM B633 | 000000000 | 0000 |
Aluminum | ||||||||||||||
M2.5 | 0.45 | M3 | 0.5 | 4 | 4.8 | Class 6g | Class 6g | 4.5 | 6.35 | 45,000 | Rockwell B56 | __ | 000000000 | 0000 |
M2.5 | 0.45 | M3.5 | 0.6 | 4 | 6.4 | Class 6g | Class 6g | 6 | 6.35 | 45,000 | Rockwell B56 | __ | 000000000 | 0000 |
M2.5 | 0.45 | M4 | 0.7 | 4 | 9.5 | Class 6g | Class 6g | 6 | 6.35 | 45,000 | Rockwell B56 | __ | 000000000 | 0000 |
18-8 Stainless Steel | ||||||||||||||
M2.5 | 0.45 | M3 | 0.35 | 7.5 | 7.5 | Class 6g | Class 6g | 6.4 | 3.2 | 85,000 | Rockwell B80 | ASTM A582 | 000000000 | 0000 |
M2.5 | 0.45 | M3 | 0.5 | 4 | 4.8 | Class 6g | Class 6g | 4.5 | 6.35 | 85,000 | Rockwell B80 | ASTM A582 | 000000000 | 0000 |
M2.5 | 0.45 | M3.5 | 0.6 | 4 | 6.4 | Class 6g | Class 6g | 6 | 6.35 | 85,000 | Rockwell B80 | ASTM A582 | 000000000 | 0000 |
M2.5 | 0.45 | M4 | 0.7 | 4 | 9.5 | Class 6g | Class 6g | 6 | 6.35 | 85,000 | Rockwell B80 | ASTM A582 | 000000000 | 0000 |
316 Stainless Steel | ||||||||||||||
M2.5 | 0.45 | M3 | 0.5 | 7.5 | 7.5 | Class 6g | Class 6g | 6.4 | 3.2 | 75,000 | Rockwell B83 | ASTM A276 | 000000000 | 0000 |
Inch-to-Metric Female Hex Thread Adapters


Adapt threaded rods from inch to metric. These adapters connect two male-threaded fasteners, so you can change the gender of a mating part or increase or decrease its thread size. The hex-shaped body fits into the head of a standard wrench. Small adapters can also be used as standoffs, positioning and separating circuit boards and other components in assemblies.
Choose black-oxide steel adapters to match the aesthetics of your system or for their mild corrosion resistance. The finish won't chip or rub off. They resist rust in indoor and dry environments, but avoid using them in corrosive environments.
Zinc-plated steel adapters are a good option in dry environments. The zinc plating prevents the steel from corroding until the plating wears away.
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.
At about a third of the weight of steel adapters, aluminum adapters are the lightest we offer. They resist corrosion in wet environments.
For technical drawings and 3-D models, click on a part number.
Thread Size | Thread Lg. | Thread Fit | Hex | Each | ||||||||||
---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
(A) | (B) | Pitch (B), mm | (A) | (B), mm | (A) | (B) | Size | Lg. | Specifications Met | Tensile Strength, psi | Hardness | 1-9 | 10-Up | |
Black-Oxide Steel | ||||||||||||||
2-56 | M2.5 | 0.45 | 0.187" | 4.8 | Class 2B | Class 6H | 3/16" | 1" | ASTM A108 | 78,000 | Rockwell B85 | 000000000 | 000000 | 00000 |
4-40 | M2.5 | 0.45 | 1/4" | 4.8 | Class 2B | Class 6H | 3/16" | 1" | ASTM A108 | 78,000 | Rockwell B85 | 000000000 | 00000 | 0000 |
6-32 | M2.5 | 0.45 | 3/8" | 4.8 | Class 2B | Class 6H | 3/16" | 1" | ASTM A108 | 78,000 | Rockwell B85 | 000000000 | 00000 | 0000 |
8-32 | M2.5 | 0.45 | 0.437" | 4.8 | Class 2B | Class 6H | 1/4" | 1 1/2" | ASTM A108 | 78,000 | Rockwell B85 | 000000000 | 00000 | 00000 |
Zinc-Plated Steel | ||||||||||||||
2-56 | M2.5 | 0.45 | 0.187" | 4.8 | Class 2B | Class 6H | 3/16" | 1" | ASTM A108, ASTM B633 | 78,000 | Rockwell B85 | 000000000 | 00000 | 0000 |
4-40 | M2.5 | 0.45 | 1/4" | 4.8 | Class 2B | Class 6H | 3/16" | 1" | ASTM A108, ASTM B633 | 78,000 | Rockwell B85 | 000000000 | 00000 | 0000 |
6-32 | M2.5 | 0.45 | 3/8" | 4.8 | Class 2B | Class 6H | 3/16" | 1" | ASTM A108, ASTM B633 | 78,000 | Rockwell B85 | 000000000 | 00000 | 0000 |
8-32 | M2.5 | 0.45 | 0.437" | 4.8 | Class 2B | Class 6H | 1/4" | 1 1/2" | ASTM A108, ASTM B633 | 78,000 | Rockwell B85 | 000000000 | 00000 | 00000 |
18-8 Stainless Steel | ||||||||||||||
2-56 | M2.5 | 0.45 | 0.187" | 4.8 | Class 2B | Class 6H | 3/16" | 1" | ASTM A582 | 85,000 | Rockwell B80 | 000000000 | 00000 | 00000 |
4-40 | M2.5 | 0.45 | 1/4" | 4.8 | Class 2B | Class 6H | 3/16" | 1" | ASTM A582 | 85,000 | Rockwell B80 | 000000000 | 00000 | 00000 |
6-32 | M2.5 | 0.45 | 3/8" | 4.8 | Class 2B | Class 6H | 3/16" | 1" | ASTM A582 | 85,000 | Rockwell B80 | 000000000 | 00000 | 00000 |
8-32 | M2.5 | 0.45 | 0.437" | 4.8 | Class 2B | Class 6H | 1/4" | 1 1/2" | ASTM A582 | 85,000 | Rockwell B80 | 000000000 | 00000 | 00000 |
Aluminum | ||||||||||||||
2-56 | M2.5 | 0.45 | 0.187" | 4.8 | Class 2B | Class 6H | 3/16" | 1" | __ | 45,000 | Rockwell B56 | 000000000 | 0000 | 0000 |
4-40 | M2.5 | 0.45 | 1/4" | 4.8 | Class 2B | Class 6H | 3/16" | 1" | __ | 45,000 | Rockwell B56 | 000000000 | 0000 | 0000 |
6-32 | M2.5 | 0.45 | 3/8" | 4.8 | Class 2B | Class 6H | 3/16" | 1" | __ | 45,000 | Rockwell B56 | 000000000 | 0000 | 0000 |
8-32 | M2.5 | 0.45 | 0.437" | 4.8 | Class 2B | Class 6H | 1/4" | 1 1/2" | __ | 45,000 | Rockwell B56 | 000000000 | 0000 | 0000 |
Metric-to-Metric Female Hex Thread Adapters


Increase or decrease metric thread size from one male-threaded part to another. Commonly used to connect two differently sized threaded rods, these adapters have a hex-shaped body, so you can tighten them with a standard wrench. You can also use them to change thread pitch or convert a male-threaded connection to a female-threaded connection. Small adapters can work as threaded standoffs, positioning and separating circuit boards and other components in assemblies.
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.
Black-oxide steel adapters have a finish that won’t chip or rub off. They match the aesthetics of many systems. They resist rust in indoor and dry environments but will degrade in outdoor and highly corrosive environments.
Zinc-plated steel adapters are a good option in dry environments. The zinc plating prevents the steel from corroding until the plating wears away.
Aluminum adapters are about one third of the weight of steel adapters. They resist corrosion in wet environments.
18-8 stainless steel adapters resist corrosion in wet environments. However, they will corrode when exposed to salt water and other chloride solutions.
316 stainless steel adapters withstand wet environments and resist corrosion caused by salt water and harsh chemicals.
For technical drawings and 3-D models, click on a part number.
Thread Size | Thread Lg. | Thread Fit | Hex | Each | ||||||||||
---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
(A) | Pitch (A), mm | (B) | Pitch (B), mm | (A), mm | (B), mm | (A) | (B) | Size, mm | Lg., mm | Specifications Met | Hardness | 1-9 | 10-Up | |
Black-Oxide Steel | ||||||||||||||
M2.5 | 0.45 | M3 | 0.5 | 4.8 | 6.4 | Class 6H | Class 6H | 4.5 | 25 | ASTM A108 | Rockwell B85 | 000000000 | 000000 | 00000 |
M3.5 | 0.6 | M2.5 | 0.45 | 9.5 | 4.8 | Class 6H | Class 6H | 6 | 37 | ASTM A108 | Rockwell B85 | 000000000 | 00000 | 00000 |
M4 | 0.7 | M2.5 | 0.45 | 11.1 | 4.8 | Class 6H | Class 6H | 6 | 37 | ASTM A108 | Rockwell B85 | 000000000 | 00000 | 00000 |
Zinc-Plated Steel | ||||||||||||||
M2.5 | 0.45 | M3 | 0.5 | 4.8 | 6.4 | Class 6H | Class 6H | 4.5 | 25 | ASTM A108, ASTM B633 | Rockwell B85 | 000000000 | 00000 | 0000 |
M3.5 | 0.6 | M2.5 | 0.45 | 9.5 | 4.8 | Class 6H | Class 6H | 6 | 37 | ASTM A108, ASTM B633 | Rockwell B85 | 000000000 | 00000 | 00000 |
M4 | 0.7 | M2.5 | 0.45 | 11.1 | 4.8 | Class 6H | Class 6H | 6 | 37 | ASTM A108, ASTM B633 | Rockwell B85 | 000000000 | 00000 | 00000 |
Aluminum | ||||||||||||||
M2.5 | 0.45 | M3 | 0.5 | 4.8 | 6.4 | Class 6H | Class 6H | 4.5 | 25 | __ | Rockwell B56 | 000000000 | 0000 | 0000 |
M3.5 | 0.6 | M2.5 | 0.45 | 9.5 | 4.8 | Class 6H | Class 6H | 6 | 37 | __ | Rockwell B56 | 000000000 | 0000 | 0000 |
M4 | 0.7 | M2.5 | 0.45 | 11.1 | 4.8 | Class 6H | Class 6H | 6 | 37 | __ | Rockwell B56 | 000000000 | 0000 | 0000 |
18-8 Stainless Steel | ||||||||||||||
M2.5 | 0.45 | M3 | 0.5 | 4.8 | 6.4 | Class 6H | Class 6H | 4.5 | 25 | ASTM A582 | Rockwell B80 | 000000000 | 00000 | 00000 |
M3 | 0.35 | M2.5 | 0.45 | 3 | 3 | Class 6H | Class 6H | 8 | 15 | ASTM A582 | Rockwell B80 | 000000000 | 0000 | 0000 |
M3.5 | 0.6 | M2.5 | 0.45 | 9.5 | 4.8 | Class 6H | Class 6H | 6 | 37 | ASTM A582 | Rockwell B80 | 000000000 | 00000 | 00000 |
M4 | 0.7 | M2.5 | 0.45 | 11.1 | 4.8 | Class 6H | Class 6H | 6 | 37 | ASTM A582 | Rockwell B80 | 000000000 | 00000 | 00000 |
316 Stainless Steel | ||||||||||||||
M3 | 0.35 | M2.5 | 0.45 | 3 | 3 | Class 6H | Class 6H | 8 | 15 | ASTM A276 | Rockwell B83 | 000000000 | 0000 | 0000 |
M3 | 0.5 | M2.5 | 0.45 | 3 | 3 | Class 6H | Class 6H | 8 | 15 | ASTM A276 | Rockwell B83 | 000000000 | 0000 | 0000 |
18-8 Stainless Steel Key-Locking Inserts

Made of stainless steel, these inserts have good corrosion resistance. Drive the keys into the surrounding material for a more secure hold than thread-locking inserts. Use them to repair or change threads in soft metals such as aluminum. Inserts may be mildly magnetic. They’re comparable to Keensert® inserts. Installation requires a drill bit, a standard tap, an installation tool, and a hammer.
Inserts with a thin wall are often used in small holes or near the edge of a workpiece.
For technical drawings and 3-D models, click on a part number.
Screw-Locking Key-Locking Inserts

Forming the strongest hold of any of our threaded inserts, these inserts have a distorted internal thread to lock screws into place and keys that drive into surrounding material to prevent slipping and rotating. This creates a mechanical lock, which is stronger than the chemical lock from adhesive on thread-locking inserts. Because they’re made of a solid piece of metal, these inserts are also stronger than helical inserts, which are made of coiled wire. They're often used in molds, tools and dies, and suspension systems in vehicles to create completely new threads, add strong threads in soft metal, or replace existing threads that are damaged or need to be resized.
A dry-film lubricant makes it easy to install them and screw fasteners in. To install, use a tap to create the threads in your material and an installation tool to drive the keys into the material. All are made to tight tolerances with strictly controlled materials. Many inch sizes also meet military or aerospace standards for dimensions and material.
These inserts resist corrosion in wet environments. Inserts with thin walls are best for small holes or near the edge of a workpiece. They’re often used in electronics that require small fasteners.
For technical drawings and 3-D models, click on a part number.
Male-Female Threaded Hex Standoffs

Position components in assemblies, as well as separate or connect parts with these standoffs. The flat sides of the hex ensure a firm grip when tightening with a wrench.
18-8 stainless steel standoffs have good corrosion resistance and may be mildly magnetic.
Aluminum standoffs are lightweight, nonmagnetic, and mildly corrosion resistant. Material can vary between 6061 and 2011 aluminum.
Zinc-plated brass standoffs are electrically conductive, nonmagnetic, and have a corrosion-resistant finish.
Nylon standoffs have excellent wear and abrasion resistance and also offer resistance to chemicals and solvents (except mineral acids). Exposure to moisture may cause them to expand.
For technical drawings and 3-D models, click on a part number.


Thread (A) | Thread (B) | Each | ||||||||
---|---|---|---|---|---|---|---|---|---|---|
Lg., mm | Size | Pitch, mm | Lg., mm | Size | Pitch, mm | Min. Lg., mm | Specifications Met | 1-9 | 10-Up | |
4.5 mm Hex Size | ||||||||||
5 | M2.5 | 0.45 | 3.9 | M2.5 | 0.45 | 1.9 | ASTM A581 or A582 | 000000000 | 00000 | 00000 |
6 | M2.5 | 0.45 | 3.9 | M2.5 | 0.45 | 2.9 | ASTM A581 or A582 | 000000000 | 0000 | 0000 |
8 | M2.5 | 0.45 | 3.9 | M2.5 | 0.45 | 4.8 | ASTM A581 or A582 | 000000000 | 0000 | 0000 |
10 | M2.5 | 0.45 | 3.9 | M2.5 | 0.45 | 4.8 | ASTM A581 or A582 | 000000000 | 0000 | 0000 |
12 | M2.5 | 0.45 | 3.9 | M2.5 | 0.45 | 4.8 | ASTM A581 or A582 | 000000000 | 0000 | 0000 |
14 | M2.5 | 0.45 | 3.9 | M2.5 | 0.45 | 4.8 | ASTM A581 or A582 | 000000000 | 0000 | 0000 |
16 | M2.5 | 0.45 | 3.9 | M2.5 | 0.45 | 4.8 | ASTM A581 or A582 | 000000000 | 0000 | 0000 |
19 | M2.5 | 0.45 | 3.9 | M2.5 | 0.45 | 4.8 | ASTM A581 or A582 | 000000000 | 0000 | 0000 |
20 | M2.5 | 0.45 | 3.9 | M2.5 | 0.45 | 4.8 | ASTM A581 or A582 | 000000000 | 0000 | 0000 |
25 | M2.5 | 0.45 | 3.9 | M2.5 | 0.45 | 4.8 | ASTM A581 or A582 | 000000000 | 0000 | 0000 |
31 | M2.5 | 0.45 | 3.9 | M2.5 | 0.45 | 4.8 | ASTM A581 or A582 | 000000000 | 0000 | 0000 |


Thread (A) | Thread (B) | Each | |||||||
---|---|---|---|---|---|---|---|---|---|
Lg., mm | Size | Pitch, mm | Lg., mm | Size | Pitch, mm | Min. Lg., mm | 1-9 | 10-Up | |
4.5 mm Hex Size | |||||||||
5 | M2.5 | 0.45 | 3.9 | M2.5 | 0.45 | 1.9 | 000000000 | 00000 | 00000 |
6 | M2.5 | 0.45 | 3.9 | M2.5 | 0.45 | 2.9 | 000000000 | 0000 | 0000 |
8 | M2.5 | 0.45 | 3.9 | M2.5 | 0.45 | 4.8 | 000000000 | 0000 | 0000 |
10 | M2.5 | 0.45 | 3.9 | M2.5 | 0.45 | 4.8 | 000000000 | 0000 | 0000 |
12 | M2.5 | 0.45 | 3.9 | M2.5 | 0.45 | 4.8 | 000000000 | 0000 | 0000 |
14 | M2.5 | 0.45 | 3.9 | M2.5 | 0.45 | 4.8 | 000000000 | 0000 | 0000 |
16 | M2.5 | 0.45 | 3.9 | M2.5 | 0.45 | 4.8 | 000000000 | 0000 | 0000 |
19 | M2.5 | 0.45 | 3.9 | M2.5 | 0.45 | 4.8 | 000000000 | 0000 | 0000 |
20 | M2.5 | 0.45 | 3.9 | M2.5 | 0.45 | 4.8 | 000000000 | 0000 | 0000 |
25 | M2.5 | 0.45 | 3.9 | M2.5 | 0.45 | 4.8 | 000000000 | 0000 | 0000 |
31 | M2.5 | 0.45 | 3.9 | M2.5 | 0.45 | 4.8 | 000000000 | 0000 | 0000 |


Thread (A) | Thread (B) | Each | ||||||||
---|---|---|---|---|---|---|---|---|---|---|
Lg., mm | Size | Pitch, mm | Lg., mm | Size | Pitch, mm | Min. Lg., mm | Specifications Met | 1-9 | 10-Up | |
4.5 mm Hex Size | ||||||||||
5 | M2.5 | 0.45 | 3.9 | M2.5 | 0.45 | 1.9 | ASTM B16 | 000000000 | 00000 | 00000 |
6 | M2.5 | 0.45 | 3.9 | M2.5 | 0.45 | 2.9 | ASTM B16 | 000000000 | 0000 | 0000 |
8 | M2.5 | 0.45 | 3.9 | M2.5 | 0.45 | 4.8 | ASTM B16 | 000000000 | 0000 | 0000 |
10 | M2.5 | 0.45 | 3.9 | M2.5 | 0.45 | 4.8 | ASTM B16 | 000000000 | 0000 | 0000 |
12 | M2.5 | 0.45 | 3.9 | M2.5 | 0.45 | 4.8 | ASTM B16 | 000000000 | 0000 | 0000 |
14 | M2.5 | 0.45 | 3.9 | M2.5 | 0.45 | 4.8 | ASTM B16 | 000000000 | 0000 | 0000 |
16 | M2.5 | 0.45 | 3.9 | M2.5 | 0.45 | 4.8 | ASTM B16 | 000000000 | 0000 | 0000 |
19 | M2.5 | 0.45 | 3.9 | M2.5 | 0.45 | 4.8 | ASTM B16 | 000000000 | 0000 | 0000 |
20 | M2.5 | 0.45 | 3.9 | M2.5 | 0.45 | 4.8 | ASTM B16 | 000000000 | 0000 | 0000 |
25 | M2.5 | 0.45 | 3.9 | M2.5 | 0.45 | 4.8 | ASTM B16 | 000000000 | 0000 | 0000 |
31 | M2.5 | 0.45 | 3.9 | M2.5 | 0.45 | 4.8 | ASTM B16 | 000000000 | 0000 | 0000 |


Thread (A) | Thread (B) | Each | ||||||||||
---|---|---|---|---|---|---|---|---|---|---|---|---|
Lg., mm | Size | Pitch, mm | Lg., mm | Size | Pitch, mm | Min. Lg., mm | Temperature Range, °F | Color | Specifications Met | 1-9 | 10-Up | |
4.5 mm Hex Size | ||||||||||||
5 | M2.5 | 0.45 | 3.9 | M2.5 | 0.45 | 1.9 | -40° to 250° | Off-White | ASTM D4066; UL 94 V-2 | 000000000 | 00000 | 00000 |
6 | M2.5 | 0.45 | 3.9 | M2.5 | 0.45 | 2.9 | -40° to 250° | Off-White | ASTM D4066; UL 94 V-2 | 000000000 | 0000 | 0000 |
8 | M2.5 | 0.45 | 3.9 | M2.5 | 0.45 | 4.8 | -40° to 250° | Off-White | ASTM D4066; UL 94 V-2 | 000000000 | 0000 | 0000 |
10 | M2.5 | 0.45 | 3.9 | M2.5 | 0.45 | 4.8 | -40° to 250° | Off-White | ASTM D4066; UL 94 V-2 | 000000000 | 0000 | 0000 |
12 | M2.5 | 0.45 | 3.9 | M2.5 | 0.45 | 4.8 | -40° to 250° | Off-White | ASTM D4066; UL 94 V-2 | 000000000 | 0000 | 0000 |
14 | M2.5 | 0.45 | 3.9 | M2.5 | 0.45 | 4.8 | -40° to 250° | Off-White | ASTM D4066; UL 94 V-2 | 000000000 | 0000 | 0000 |
16 | M2.5 | 0.45 | 3.9 | M2.5 | 0.45 | 4.8 | -40° to 250° | Off-White | ASTM D4066; UL 94 V-2 | 000000000 | 0000 | 0000 |
19 | M2.5 | 0.45 | 3.9 | M2.5 | 0.45 | 4.8 | -40° to 250° | Off-White | ASTM D4066; UL 94 V-2 | 000000000 | 0000 | 0000 |
20 | M2.5 | 0.45 | 3.9 | M2.5 | 0.45 | 4.8 | -40° to 250° | Off-White | ASTM D4066; UL 94 V-2 | 000000000 | 0000 | 0000 |
25 | M2.5 | 0.45 | 3.9 | M2.5 | 0.45 | 4.8 | -40° to 250° | Off-White | ASTM D4066; UL 94 V-2 | 000000000 | 0000 | 0000 |
31 | M2.5 | 0.45 | 3.9 | M2.5 | 0.45 | 4.8 | -40° to 250° | Off-White | ASTM D4066; UL 94 V-2 | 000000000 | 0000 | 0000 |