About Nuts, Materials, and Finishes
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About Set Screws
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About Socket Head Screws
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About Rounded Head Screws
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About Flat Head Screws
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How to Install Helical Inserts
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About Helical Insert Length
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Alloy Steel Socket Head Screws


With a tensile strength of 170,000 psi, these alloy steel screws are stronger than Grade 8 steel screws. Length is measured from under the head.
Black-oxide steel screws are mildly corrosion resistant in dry environments. Fine and extra-fine threads are closely spaced to prevent loosening from vibration; the finer the thread, the better the resistance. They are not compatible with coarse threads.
For technical drawings and 3-D models, click on a part number.
Head | |||||||||||
---|---|---|---|---|---|---|---|---|---|---|---|
Lg. | Threading | Min. Thread Lg. | Thread Spacing | Dia. | Ht. | Drive Size | Tensile Strength, psi | Specifications Met | Pkg. Qty. | Pkg. | |
3-56 | |||||||||||
Black-Oxide Alloy Steel | |||||||||||
1/8" | Fully Threaded | __ | Fine | 0.161" | 0.099" | 5/64" | 170,000 | ASTM A574 | 10 | 000000000 | 000000 |
3/16" | Fully Threaded | __ | Fine | 0.161" | 0.099" | 5/64" | 170,000 | ASTM A574 | 5 | 000000000 | 0000 |
1/4" | Fully Threaded | __ | Fine | 0.161" | 0.099" | 5/64" | 170,000 | ASTM A574 | 5 | 000000000 | 0000 |
5/16" | Fully Threaded | __ | Fine | 0.161" | 0.099" | 5/64" | 170,000 | ASTM A574 | 5 | 000000000 | 0000 |
3/8" | Fully Threaded | __ | Fine | 0.161" | 0.099" | 5/64" | 170,000 | ASTM A574 | 5 | 000000000 | 0000 |
1/2" | Fully Threaded | __ | Fine | 0.161" | 0.099" | 5/64" | 170,000 | ASTM A574 | 5 | 000000000 | 0000 |
3/4" | Fully Threaded | __ | Fine | 0.161" | 0.099" | 5/64" | 170,000 | ASTM A574 | 5 | 000000000 | 0000 |
1" | Partially Threaded | 5/8" | Fine | 0.161" | 0.099" | 5/64" | 170,000 | ASTM A574 | 5 | 000000000 | 00000 |
18-8 Stainless Steel Socket Head Screws


Made from 18-8 stainless steel, these screws have good chemical resistance and may be mildly magnetic. Length is measured from under the head. Fine threads are closely spaced to prevent loosening from vibration. They are not compatible with coarse threads.
Screws that meet ASME B1.1, ASME B18.3, ISO 21269, and ISO 4762 (formerly DIN 912) comply with standards for dimensions.
For technical drawings and 3-D models, click on a part number.
Head | |||||||||||
---|---|---|---|---|---|---|---|---|---|---|---|
Lg. | Threading | Min. Thread Lg. | Thread Spacing | Dia. | Ht. | Drive Size | Tensile Strength, psi | Specifications Met | Pkg. Qty. | Pkg. | |
3-56 | |||||||||||
18-8 Stainless Steel | |||||||||||
1/8" | Fully Threaded | __ | Fine | 0.161" | 0.099" | 5/64" | 70,000 | ASME B18.3 | 100 | 000000000 | 00000 |
3/16" | Fully Threaded | __ | Fine | 0.161" | 0.099" | 5/64" | 70,000 | ASME B18.3 | 100 | 000000000 | 0000 |
1/4" | Fully Threaded | __ | Fine | 0.161" | 0.099" | 5/64" | 70,000 | ASME B18.3 | 25 | 000000000 | 0000 |
5/16" | Fully Threaded | __ | Fine | 0.161" | 0.099" | 5/64" | 70,000 | ASME B18.3 | 50 | 000000000 | 00000 |
3/8" | Fully Threaded | __ | Fine | 0.161" | 0.099" | 5/64" | 70,000 | ASME B18.3 | 25 | 000000000 | 0000 |
1/2" | Fully Threaded | __ | Fine | 0.161" | 0.099" | 5/64" | 70,000 | ASME B18.3 | 50 | 000000000 | 00000 |
5/8" | Fully Threaded | __ | Fine | 0.161" | 0.099" | 5/64" | 70,000 | ASME B18.3 | 50 | 000000000 | 00000 |
3/4" | Fully Threaded | __ | Fine | 0.161" | 0.099" | 5/64" | 70,000 | ASME B18.3 | 50 | 000000000 | 00000 |
1" | Partially Threaded | 5/8" | Fine | 0.161" | 0.099" | 5/64" | 70,000 | ASME B18.3 | 100 | 000000000 | 0000 |
18-8 Stainless Steel Button Head Hex Drive Screws
18-8 stainless steel button head screws have good chemical resistance and may be mildly magnetic. Length is measured from under the head.
Passivated stainless steel screws provide added protection against oxidation and corrosion.
For technical drawings and 3-D models, click on a part number.

Lg. | Threading | Head Dia. | Head Ht. | Drive Size | Finish | Tensile Strength, psi | Specifications Met | Pkg. Qty. | Pkg. | |
3-56 | ||||||||||
---|---|---|---|---|---|---|---|---|---|---|
1/4" | Fully Threaded | 0.188" | 0.052" | 1/16" | Passivated | 70,000 | ASME B18.3 | 25 | 000000000 | 00000 |
3/8" | Fully Threaded | 0.188" | 0.052" | 1/16" | Passivated | 70,000 | ASME B18.3 | 25 | 000000000 | 0000 |
1/2" | Fully Threaded | 0.188" | 0.052" | 1/16" | Passivated | 70,000 | ASME B18.3 | 10 | 000000000 | 0000 |
Alloy Steel Button Head Hex Drive Screws

Made from alloy steel, these screws are nearly twice as strong as stainless steel button head screws. Length is measured from under the head.
Black-oxide alloy steel screws are mildly corrosion resistant in dry environments.
For technical drawings and 3-D models, click on a part number.
Lg. | Threading | Head Dia. | Head Ht. | Drive Size | Tensile Strength, psi | Specifications Met | Pkg. Qty. | Pkg. | |
Black-Oxide Alloy Steel | |||||||||
---|---|---|---|---|---|---|---|---|---|
3-56 | |||||||||
1/4" | Fully Threaded | 0.188" | 0.052" | 1/16" | 120,000 | ASME B18.3;ASTM F835 | 10 | 000000000 | 00000 |
3/8" | Fully Threaded | 0.188" | 0.052" | 1/16" | 120,000 | ASME B18.3;ASTM F835 | 10 | 000000000 | 0000 |
1/2" | Fully Threaded | 0.188" | 0.052" | 1/16" | 120,000 | ASME B18.3;ASTM F835 | 10 | 000000000 | 00000 |
Brass Button Head Hex Drive Screws

Brass button head screws are corrosion resistant in wet environments, nonmagnetic, and electrically conductive. Length is measured from under the head.
For technical drawings and 3-D models, click on a part number.
18-8 Stainless Steel Pan Head Phillips Screws

18-8 stainless steel pan head screws have good chemical resistance and may be mildly magnetic. Length is measured from under the head. For partially threaded screws thread length may vary from the minimum thread length published to fully threaded.
Passivated stainless steel screws provide added protection against oxidation and corrosion.
For technical drawings and 3-D models, click on a part number.
Lg. | Threading | Head Dia. | Head Ht. | Drive Size | Tensile Strength, psi | Specifications Met | Pkg. Qty. | Pkg. | |
Passivated 18-8 Stainless Steel | |||||||||
---|---|---|---|---|---|---|---|---|---|
3-56 | |||||||||
1/8" | Fully Threaded | 0.193" | 0.071" | No. 1 | 70,000 | ASME B18.6.3 | 100 | 000000000 | 000000 |
3/16" | Fully Threaded | 0.193" | 0.071" | No. 1 | 70,000 | ASME B18.6.3 | 100 | 000000000 | 0000 |
1/4" | Fully Threaded | 0.193" | 0.071" | No. 1 | 70,000 | ASME B18.6.3 | 100 | 000000000 | 0000 |
5/16" | Fully Threaded | 0.193" | 0.071" | No. 1 | 70,000 | ASME B18.6.3 | 100 | 000000000 | 0000 |
3/8" | Fully Threaded | 0.193" | 0.071" | No. 1 | 70,000 | ASME B18.6.3 | 100 | 000000000 | 0000 |
7/16" | Fully Threaded | 0.193" | 0.071" | No. 1 | 70,000 | ASME B18.6.3 | 100 | 000000000 | 0000 |
1/2" | Fully Threaded | 0.193" | 0.071" | No. 1 | 70,000 | ASME B18.6.3 | 100 | 000000000 | 0000 |
5/8" | Fully Threaded | 0.193" | 0.071" | No. 1 | 70,000 | ASME B18.6.3 | 100 | 000000000 | 0000 |
3/4" | Fully Threaded | 0.193" | 0.071" | No. 1 | 70,000 | ASME B18.6.3 | 50 | 000000000 | 0000 |
1" | Fully Threaded | 0.193" | 0.071" | No. 1 | 70,000 | ASME B18.6.3 | 50 | 000000000 | 0000 |
Alloy Steel Hex Drive Flat Head Screws


Made from alloy steel, these screws are nearly twice as strong as stainless steel flat head screws. They're angled under the head to sit flush within countersunk holes. Length is measured from the top of the head.
Black-oxide alloy steel screws have mild corrosion resistance in dry environments.
For technical drawings and 3-D models, click on a part number.
Lg. | Threading | Flat Head Profile | Head Dia. | Head Ht. | Drive Size | Tensile Strength, psi | Specifications Met | Pkg. Qty. | Pkg. | |
Black-Oxide Alloy Steel | ||||||||||
---|---|---|---|---|---|---|---|---|---|---|
3-56 | ||||||||||
1/4" | Fully Threaded | Standard | 0.226" | 0.073" | 1/16" | 130,000 | ASTM F835 | 10 | 000000000 | 000000 |
3/8" | Fully Threaded | Standard | 0.226" | 0.073" | 1/16" | 130,000 | ASTM F835 | 10 | 000000000 | 00000 |
1/2" | Fully Threaded | Standard | 0.226" | 0.073" | 1/16" | 130,000 | ASTM F835 | 10 | 000000000 | 00000 |
18-8 Stainless Steel Phillips Flat Head Screws


These screws have good chemical resistance and may be mildly magnetic. They’re angled under the head to sit flush within countersunk holes. Length is measured from the top of the head.
Passivated stainless steel screws provide added protection against oxidation and corrosion.
For technical drawings and 3-D models, click on a part number.
Lg. | Threading | Flat Head Profile | Head Dia. | Head Ht. | Drive Size | Tensile Strength, psi | Specifications Met | Pkg. Qty. | Pkg. | |
Passivated 18-8 Stainless Steel—82° Countersink Angle | ||||||||||
---|---|---|---|---|---|---|---|---|---|---|
3-56 | ||||||||||
3/16" | Fully Threaded | Standard | 0.187" | 0.059" | No. 1 | 80,000 | ASME B18.6.3 | 100 | 000000000 | 00000 |
1/4" | Fully Threaded | Standard | 0.187" | 0.059" | No. 1 | 80,000 | ASME B18.6.3 | 100 | 000000000 | 0000 |
3/8" | Fully Threaded | Standard | 0.187" | 0.059" | No. 1 | 80,000 | ASME B18.6.3 | 100 | 000000000 | 0000 |
Alloy Steel Cup-Point Set Screws

Made from alloy steel, these set screws have a thin edge that digs into hard surfaces for a secure hold. Length listed is the overall length.
Black-oxide alloy steel set screws resist corrosion in dry environments.
For technical drawings and 3-D models, click on a part number.
Lg. | Drive Size | Hardness | Specifications Met | Pkg. Qty. | Pkg. | |
Black-Oxide Alloy Steel | ||||||
---|---|---|---|---|---|---|
3-56 | ||||||
3/32" | 0.050" | Rockwell C45 | ASME B18.3, ASTM F912 | 10 | 000000000 | 00000 |
1/8" | 0.050" | Rockwell C45 | ASME B18.3, ASTM F912 | 10 | 000000000 | 0000 |
3/16" | 0.050" | Rockwell C45 | ASME B18.3, ASTM F912 | 10 | 000000000 | 0000 |
1/4" | 0.050" | Rockwell C45 | ASME B18.3, ASTM F912 | 10 | 000000000 | 0000 |
3/8" | 0.050" | Rockwell C45 | ASME B18.3, ASTM F912 | 10 | 000000000 | 0000 |
18-8 Stainless Steel Cup-Point Set Screws

Made from 18-8 stainless steel, these set screws are chemical resistant and may be mildly magnetic. They have a thin edge that digs into the contact surface for a secure hold. Length listed is the overall length.
For technical drawings and 3-D models, click on a part number.
Lg. | Drive Size | Hardness | Specifications Met | Pkg. Qty. | Pkg. | |
18-8 Stainless Steel | ||||||
---|---|---|---|---|---|---|
3-56 | ||||||
1/16" | 0.050" | Rockwell B80 | ASME B18.3 | 10 | 000000000 | 00000 |
3/32" | 0.050" | Rockwell B80 | ASME B18.3 | 10 | 000000000 | 0000 |
1/8" | 0.050" | Rockwell B80 | ASME B18.3 | 10 | 000000000 | 0000 |
3/16" | 0.050" | Rockwell B80 | ASME B18.3 | 10 | 000000000 | 0000 |
1/4" | 0.050" | Rockwell B80 | ASME B18.3 | 10 | 000000000 | 0000 |
5/16" | 0.050" | Rockwell B80 | ASME B18.3 | 10 | 000000000 | 0000 |
3/8" | 0.050" | Rockwell B80 | ASME B18.3 | 10 | 000000000 | 0000 |
18-8 Stainless Steel Extended-Tip Set Screws

Made from 18-8 stainless steel, these set screws are chemical resistant and may be mildly magnetic. They have a protruding tip that locks within a mating hole or slot to keep parts aligned. They're also known as half dog-point set screws. Length listed is the overall length.
For technical drawings and 3-D models, click on a part number.
Tip | ||||||||
---|---|---|---|---|---|---|---|---|
Lg. | Dia. | Lg. | Drive Size | Hardness | Specifications Met | Pkg. Qty. | Pkg. | |
18-8 Stainless Steel | ||||||||
3-56 | ||||||||
1/8" | 0.066" | 0.027" | 0.050" | Rockwell B80 | ASME B18.3 | 25 | 000000000 | 000000 |
Low-Strength Steel Hex Nuts

About half the strength of medium-strength steel nuts, these nuts are for light duty fastening applications, such as securing access panels.
Zinc-plated steel nuts resist corrosion in wet environments.
For technical drawings and 3-D models, click on a part number.
Thread Size | Wd. | Ht. | Specifications Met | Pkg. Qty. | Pkg. | |
Zinc-Plated Steel | ||||||
---|---|---|---|---|---|---|
3-56 | 3/16" | 1/16" | ASME B18.6.3 | 50 | 000000000 | 00000 |
18-8 Stainless Steel Hex Nuts

These nuts have good chemical resistance and may be mildly magnetic.
For technical drawings and 3-D models, click on a part number.
Thread Size | Wd. | Ht. | Pkg. Qty. | Pkg. | |
18-8 Stainless Steel | |||||
---|---|---|---|---|---|
3-56 | 3/16" | 1/16" | 100 | 000000000 | 00000 |
Brass Hex Nuts

These nuts are corrosion resistant in wet environments, electrically conductive, and nonmagnetic.
For technical drawings and 3-D models, click on a part number.
Thread Size | Wd. | Ht. | Pkg. Qty. | Pkg. | |
Brass | |||||
---|---|---|---|---|---|
3-56 | 3/16" | 1/16" | 100 | 000000000 | 00000 |
18-8 Stainless Steel Nylon-Insert Locknuts

These locknuts have good chemical resistance and may be mildly magnetic. The nylon insert grips the bolt to resist loosening without damaging threads. They're reusable, but their holding power lessens with each use.
For technical drawings and 3-D models, click on a part number.
Thread Size | Wd. | Ht. | Insert Max. Temp., °F | Pkg. Qty. | Pkg. | |
18-8 Stainless Steel | ||||||
---|---|---|---|---|---|---|
3-56 | 1/4" | 9/64" | 220° | 25 | 000000000 | 00000 |
18-8 Stainless Steel Flange Nuts

Made from 18-8 stainless steel, these flange nuts have good chemical resistance. The flange distributes pressure where the nut meets the material surface, eliminating the need for a separate washer. Height includes the flange.
For technical drawings and 3-D models, click on a part number.
Flange | ||||||
---|---|---|---|---|---|---|
Thread Size | Wd. | Ht. | Dia. | Thick. | Each | |
18-8 Stainless Steel | ||||||
3-56 | 15/64" | 1/8" | 15/64" | 0.03" | 000000000 | 00000 |
Stainless Steel Helical Inserts

Also known as Heli-Coil inserts, these inserts have coils that expand once installed to securely anchor the insert. All have a prong for ease of installation. An installation tool grips the prong and reduces the coil diameter, enabling the insert to fit in tapped holes. Remove the prong to insert the screw. Installation requires a drill bit, a helical insert tap, an installation tool, and a prong break-off tool.
For technical drawings and 3-D models, click on a part number.
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. | Specifications Met | Pkg. Qty. | Pkg. | Each | Each | Each | Each | |||||
18-8 Stainless Steel—Right-Hand Threaded | |||||||||||||||
3-56 | 0.099" | No. 36 | 0.1065" | MS124-670 | 10 | 000000000 | 00000 | 000000000 | 000000 | 000000000 | 000000 | 000000000 | 0000000 | 000000000 | 000000 |
3-56 | 0.148" | No. 36 | 0.1065" | MS124-710 | 10 | 000000000 | 0000 | 000000000 | 00000 | 000000000 | 00000 | 000000000 | 000000 | 000000000 | 00000 |
Stainless Steel Screw-Locking Helical Inserts

A distorted thread grips the screw to resist loosening. Also known as Heli-Coil inserts, these inserts have coils that expand once installed to securely anchor the insert. All have a prong for ease of installation. An installation tool grips the prong and reduces the coil diameter, enabling the insert to fit in tapped holes. Remove the prong to insert the screw. Installation requires a drill bit, a helical insert tap, an installation tool, and a prong break-off tool.
For technical drawings and 3-D models, click on a part number.
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. | Specifications Met | Pkg. Qty. | Pkg. | Each | Each | Each | Each | |||||
18-8 Stainless Steel | |||||||||||||||
3-56 | 0.099" | No. 36 | 0.1065" | MS21209F0310, NASM21209 | 10 | 000000000 | 00000 | 000000000 | 000000 | 000000000 | 000000 | 000000000 | 0000000 | 000000000 | 000000 |
3-56 | 0.148" | No. 36 | 0.1065" | MS21209F0315, NASM21209 | 5 | 000000000 | 0000 | 000000000 | 00000 | 000000000 | 00000 | 000000000 | 000000 | 000000000 | 00000 |