How to Install Helical Inserts
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About Helical Insert Length
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Selecting Compatible Lead Screws and Nuts
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How to Install Key-Locking Inserts
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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.
Inserts | Through-Hole Taps | Closed-End Hole Taps | Installation Tools | ||||||||||
---|---|---|---|---|---|---|---|---|---|---|---|---|---|
Thread Size | Installed Lg. | Drill Bit Size | For Max. Hole Dia. | Specifications Met | Pkg. Qty. | Pkg. | Each | Each | Each | ||||
18-8 Stainless Steel—Right-Hand Threaded | |||||||||||||
9/16"-18 | 0.562" | 37/64" | 37/64" | MS124-661 | 5 | 000000000 | 000000 | 000000000 | 000000 | 000000000 | 0000000 | 000000000 | 0000000 |
9/16"-18 | 0.844" | 37/64" | 37/64" | MS124-701 | 5 | 000000000 | 00000 | 000000000 | 00000 | 000000000 | 000000 | 000000000 | 000000 |
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.
Inserts | Through-Hole Taps | Closed-End Hole Taps | Installation Tools | ||||||||||
---|---|---|---|---|---|---|---|---|---|---|---|---|---|
Thread Size | Installed Lg. | Drill Bit Size | For Max. Hole Dia. | Specifications Met | Pkg. Qty. | Pkg. | Each | Each | Each | ||||
18-8 Stainless Steel | |||||||||||||
9/16"-18 | 0.562" | 37/64" | 37/64" | MS21209F9-10, NASM21209 | 1 | 000000000 | 00000 | 000000000 | 000000 | 000000000 | 0000000 | 000000000 | 0000000 |
9/16"-18 | 0.844" | 37/64" | 37/64" | MS21209F9-15, NASM21209 | 1 | 000000000 | 0000 | 000000000 | 00000 | 000000000 | 000000 | 000000000 | 000000 |
Helical Inserts with Installation Tools

Inserts come with a through-hole tap and installation tool. Also known as Heli-Coil inserts, they 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.
Thread Size | Installed Lg. | Drill Bit Size | For Max. Hole Dia. | No. of Inserts Included | Includes | Each | |
18-8 Stainless Steel—Right-Hand Threaded | |||||||
---|---|---|---|---|---|---|---|
9/16"-18 | 0.844" | 37/64" | 37/64" | 6 | Drill Bit, Through-Hole Tap, Installation Tool | 000000000 | 0000000 |
Black-Phosphate Steel Key-Locking Inserts

A black-phosphate finish provides mild 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. They’re comparable to Keensert® inserts. Installation requires a drill bit, a standard tap, an installation tool, and a hammer.
Choose inserts with a thick wall for greater strength than thin-wall inserts, or to fill a large hole with stripped threads.
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.
Choose inserts with a thick wall for greater strength than thin-wall inserts, or to fill a large hole.
Mil. Spec. Stainless Steel Key-Locking Inserts

These inserts are made to stringent military specifications. 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.
Choose inserts with a thick wall for greater strength than thin-wall inserts, or to fill a large hole.
Inserts | Installation Tools | |||||||||
---|---|---|---|---|---|---|---|---|---|---|
Thread Size | For Tap Thread Size | Installed Lg. | Drill Bit Size | For Max. Hole Dia. | No. of Locking Keys | Specifications Met | Each | Each | ||
18-8 Stainless Steel with Thick Wall | ||||||||||
9/16"-18 | 13/16"-16 | 13/16" | 49/64" | 0.771" | 4 | MS51831-207, NAS1395C9 | 000000000 | 000000 | 000000000 | 000000 |
18-8 Stainless Steel with Extra Thick Wall | ||||||||||
9/16"-18 | 7/8"-14 | 13/16" | 53/64" | 0.833" | 4 | MS51832-207 | 000000000 | 00000 | 000000000 | 00000 |
Mil. Spec. Alloy Steel Key-Locking Inserts

The strongest key-locking inserts we offer, these inserts are made to stringent military specifications. 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.
Choose inserts with a thick wall for greater strength than thin-wall inserts, or to fill a large hole.
Key-Locking Inserts with Installation Tool

Drive the keys into the surrounding material for a more secure hold than thread-locking inserts. These inserts are used to repair or convert threads in soft metals such as aluminum. They’re comparable to Keensert® inserts.
18-8 stainless steel inserts are more corrosion resistant than black-phosphate steel. They may be mildly magnetic.
Black-phosphate steel inserts are mildly corrosion resistant.
Choose inserts with a thick wall for greater strength than thin-wall inserts, or to fill a large hole.
Key-Locking Insert Assortments with Installation Tool

These assortments include various sizes of key-locking inserts with thick and thin walls, and an installation tool. Drive the keys into the surrounding material for a more secure hold than thread-locking inserts. Use them to repair or convert threads in soft metals such as aluminum. They’re comparable to Keensert® inserts.
18-8 stainless steel inserts are more corrosion resistant than black-phosphate steel. They may be mildly magnetic.
Black-phosphate steel inserts are mildly corrosion resistant.
Choose assortments with thick-wall inserts for greater strength than thin-wall inserts, or to fill a large hole.
For Tap | ||||||
---|---|---|---|---|---|---|
Includes | No. of Inserts Included | Thread Size | Drill Bit Size | For Max. Hole Dia. | Each | |
Inch | ||||||
18-8 Stainless Steel with Thick Wall | ||||||
1/4"-28 Thread × 3/8" Installed Lg. (20 Each) 5/16"-24 Thread × 0.438" Installed Lg. (15 Each) 3/8"-24 Thread × 1/2" Installed Lg. (10 Each) 7/16"-20 Thread × 5/8" Installed Lg. (10 Each) 1/2"-20 Thread × 5/8" Installed Lg. (6 Each) 9/16"-18 Thread × 0.813" Installed Lg. (5 Each) 5/8"-18 Thread × 7/8" Installed Lg. (3 Each) 3/4"-16 Thread × 1 1/8" Installed Lg. (3 Each) 7/8"-14 Thread × 1 1/4" Installed Lg. (3 Each) 1"-12 Thread × 1 3/8" Installed Lg. (2 Each) Installation Tool | 77 | 7/16"-14 1/2"-13 9/16"-12 5/8"-11 3/4"-16 7/8"-14 1 1/8"-12 1 1/4"-12 1 3/8"-12 | X 29/64" 33/64" 37/64" 45/64" 53/64" 1 1/16" 1 3/16" 1 5/16" | 0.397" 29/64" 33/64" 37/64" 45/64" 53/64" 1 1/16" 1 3/16" 1 5/16" | 000000000 | 0000000 |
Black-Phosphate Steel with Thick Wall | ||||||
1/4"-28 Thread × 3/8" Installed Lg. (20 Each) 5/16"-24 Thread × 0.438" Installed Lg. (15 Each) 3/8"-24 Thread × 1/2" Installed Lg. (10 Each) 7/16"-20 Thread × 5/8" Installed Lg. (10 Each) 1/2"-20 Thread × 5/8" Installed Lg. (6 Each) 9/16"-18 Thread × 0.813" Installed Lg. (5 Each) 5/8"-18 Thread × 7/8" Installed Lg. (3 Each) 3/4"-16 Thread × 1 1/8" Installed Lg. (3 Each) 7/8"-14 Thread × 1 1/4" Installed Lg. (3 Each) 1"-12 Thread × 1 3/8" Installed Lg. (2 Each) Installation Tool | 77 | 7/16"-14 1/2"-13 9/16"-12 5/8"-11 3/4"-16 7/8"-14 1 1/8"-12 1 1/4"-12 1 3/8"-12 | X 29/64" 33/64" 37/64" 45/64" 53/64" 1 1/16" 1 3/16" 1 5/16" | 0.397" 29/64" 33/64" 37/64" 45/64" 53/64" 1 1/16" 1 3/16" 1 5/16" | 000000000 | 000000 |
Black-Phosphate Steel Easy-to-Install Thread-Locking Inserts
A black-phosphate finish provides mild corrosion resistance. Also known as E-Z Lok, these inserts use Loctite® adhesive to keep them in place. The adhesive reaches full strength after 72 hours. Installation requires a drill bit and a standard tap. Then set the insert with a bolt and two nuts, or use an installation bit.
Choose inserts with a thick wall for greater strength than thin-wall inserts, or to fill a large hole.
To drive slotted inserts, you can use a slotted screwdriver instead of using an installation bit or a bolt and two nuts.


For Tap | |||||||||
---|---|---|---|---|---|---|---|---|---|
Thread Size | Thread Pitch, mm | Thread Spacing | Thread Size | Installed Lg. | Drill Bit Size | For Max. Hole Dia. | Pkg. Qty. | Pkg. | |
Black-Phosphate Steel with Thick Wall | |||||||||
M10 | 1 | Extra Fine | 9/16"-18 | 29/64" | 33/64" | 33/64" | 1 | 000000000 | 00000 |
18-8 Stainless Steel Easy-to-Install Thread-Locking Inserts
Made of 18-8 stainless steel, these inserts have good corrosion resistance. Also known as E-Z Lok, they use Loctite® adhesive to keep them in place. The adhesive reaches full strength after 72 hours. They may be mildly magnetic. Installation requires a drill bit and a standard tap. Then set the insert with an installation bit, a slotted screwdriver, or a bolt with two nuts.
Inserts with a thin wall are often used in small holes or near the edge of a workpiece.


Alloy Steel Thin-Wall Swage-Locking Inserts



Add or repair threads near the edges and corners of soft metal surfaces—these inserts have thinner walls than any of our key-locking and thread-locking inserts. With knurls that press (swage) into the surrounding material, they won’t budge when you tighten a screw. Made of alloy steel, they’re stronger than our 17-4 PH stainless steel inserts. They absorb impact without fracturing and stand up to high-pressure applications. A cadmium plating keeps them from corroding in wet environments. On top of the plating is a dry film lubricant to help these inserts thread in without sticking. Meeting the strict standards for MIL-I-45932/1, these inserts have highly precise threads and tight tolerances.
To install these inserts, you need a drill bit, a counterbore, a standard-sized tap, an installation tool, and a hammer. Drill a hole, counterbore the top, then tap it. Place the insert into the installation tool and hand-tighten it into the tapped hole. Hammer the tool to secure the insert in place, driving the knurls into the surrounding material.
17-4 PH Stainless Steel Thin-Wall Swage-Locking Inserts



Position strong, corrosion-resistant threads close to the edges of soft metal surfaces. These inserts have thinner walls than our key-locking and thread-locking inserts, so they don’t need as much space around them. Even as you tighten or loosen a screw, these inserts won’t budge—their knurls press (swage) into the surrounding material to keep them in place. They’re made of 17-4 PH stainless steel, which has the strength of steel and the corrosion resistance of 18-8 stainless steel. Manufactured to tight tolerances, these inserts meet the strict standards of MIL-I-45932/1.
To install these inserts, you need a drill bit, a counterbore, a standard-sized tap, an installation tool, and a hammer. Drill a hole, counterbore the top, and tap it. Place the insert into the installation tool, then hand-tighten it into the tapped hole. Hammer away at the tool to secure the insert and drive the knurls into the surrounding material.
Precision Acme Lead Screws and Nuts

Pair with a motor in automated motion and positioning applications. A tight thread fit allows these lead screws and nuts to make accurate, repeatable starts and stops. Also known as single-start and self-locking lead screws and nuts, they have a single thread that runs the length of the screw. The nut travels only when the screw turns, so your system won’t unexpectedly move when the lead screw is at rest. To ensure compatibility, please select components that have the same thread direction, thread size, and number of thread starts.
Carbon steel lead screws and flanges have good machinability. Black-oxide alloy steel lead screws are hard and strong. They have mild corrosion resistance and a dark surface color. 303 and 304 stainless steel lead screws and flanges have good corrosion resistance.
932 bearing bronze and 673 bronze nuts are wear resistant. They have good machinability and fair corrosion resistance. 360 brass nuts have excellent machinability and good corrosion resistance. PET plastic nuts are lightweight and corrosion resistant. PEEK plastic nuts handle twice as much heat as PET and acetal plastic nuts. They have good chemical resistance and excellent corrosion resistance.
Travel distance per turn, also known as screw lead, is the distance a nut moves with one revolution of the lead screw.

Combine externally threaded nuts with a flange to create a custom flange nut.
External Thread | ||||||||||||||
---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
Thread Type | Thread Size | Lg. | Dia. | No. of Thread Starts | Speed Ratio | Travel Distance per Turn | Size | Lg. | Thread Fit | Hardness | Dynamic Thrust Load Cap., lbs. | Temperature Range, °F | Each | |
360 Brass | ||||||||||||||
Acme | 1/4"-20 | 5/8" | 0.688" | 1 | 1:1 | 0.05" | 9/16"-18 | 3/8" | Class 2C | Brinell 141 | 310 | __ | 000000000 | 000000 |
673 Bronze | ||||||||||||||
Acme | 1/4"-16 | 5/8" | 0.688" | 1 | 1:1 | 0.063" | 9/16"-18 | 3/8" | Class 2C | Brinell 70 | Not Rated | __ | 000000000 | 00000 |
Acme | 3/8"-12 | 5/8" | 0.688" | 1 | 1:1 | 0.083" | 9/16"-18 | 3/8" | Class 2C | Brinell 70 | Not Rated | __ | 000000000 | 00000 |
Acme | 3/8"-16 | 5/8" | 0.688" | 1 | 1:1 | 0.063" | 9/16"-18 | 3/8" | Class 2C | Brinell 70 | Not Rated | __ | 000000000 | 00000 |
Stub Acme | 3/8"-8 | 5/8" | 0.688" | 1 | 1:1 | 0.125" | 9/16"-18 | 3/8" | Class 2C | Brinell 70 | Not Rated | __ | 000000000 | 00000 |
Stub Acme | 3/8"-10 | 5/8" | 0.688" | 1 | 1:1 | 0.1" | 9/16"-18 | 3/8" | Class 2C | Brinell 70 | Not Rated | __ | 000000000 | 00000 |
PET Plastic | ||||||||||||||
Acme | 1/4"-16 | 5/8" | 0.688" | 1 | 1:1 | 0.063" | 9/16"-18 | 3/8" | Class 2C | Not Rated | 160 | 15° to 175° | 000000000 | 00000 |
Acme | 1/4"-20 | 5/8" | 0.688" | 1 | 1:1 | 0.05" | 9/16"-18 | 3/8" | Class 2C | Not Rated | 160 | 15° to 175° | 000000000 | 00000 |
Acme | 3/8"-8 | 5/8" | 0.688" | 1 | 1:1 | 0.125" | 9/16"-18 | 3/8" | Class 2C | Not Rated | 350 | 15° to 175° | 000000000 | 00000 |
Acme | 3/8"-10 | 5/8" | 0.688" | 1 | 1:1 | 0.1" | 9/16"-18 | 3/8" | Class 2C | Not Rated | 350 | 15° to 175° | 000000000 | 00000 |
Acme | 3/8"-12 | 5/8" | 0.688" | 1 | 1:1 | 0.083" | 9/16"-18 | 3/8" | Class 2C | Not Rated | 350 | 15° to 175° | 000000000 | 00000 |
Acme | 3/8"-16 | 5/8" | 0.688" | 1 | 1:1 | 0.063" | 9/16"-18 | 3/8" | Class 2C | Not Rated | 350 | 15° to 175° | 000000000 | 00000 |
PEEK Plastic | ||||||||||||||
Acme | 1/4"-20 | 5/8" | 0.688" | 1 | 1:1 | 0.05" | 9/16"-18 | 3/8" | Class 2C | Not Rated | 150 | -40° to 525° | 000000000 | 000000 |

Combine externally threaded nuts with a flange to create a custom flange nut.
External Thread | |||||||||||||
---|---|---|---|---|---|---|---|---|---|---|---|---|---|
Thread Type | Thread Size | Lg. | Dia. | No. of Thread Starts | Speed Ratio | Travel Distance per Turn | Size | Lg. | Thread Fit | Hardness | Dynamic Thrust Load Cap., lbs. | Each | |
673 Bronze | |||||||||||||
Acme | 1/4"-16 | 5/8" | 0.688" | 1 | 1:1 | 0.063" | 9/16"-18 | 3/8" | Class 2C | Brinell 70 | Not Rated | 000000000 | 000000 |
Acme | 3/8"-12 | 5/8" | 0.688" | 1 | 1:1 | 0.083" | 9/16"-18 | 3/8" | Class 2C | Brinell 70 | Not Rated | 000000000 | 00000 |


Thread onto an externally threaded acme nut to create a custom flange nut.
Carbon steel flanges have good machinability. However, they will rust when exposed to moisture. Black-oxide carbon steel flanges have mild corrosion resistance in dry environments and a dark surface color. 303 stainless steel flanges have good corrosion resistance.
Fast-Travel Precision Acme Lead Screws and Nuts

Multiple thread channels (also known as thread starts) create faster linear travel than lead screws with a single thread start. The threads have a tight thread fit for accurate, repeatable starts and stops. Pair with a motor in automated motion and positioning applications. To ensure compatibility, please select components that have the same thread direction, thread size, and number of thread starts.
Carbon steel lead screws and flanges have good machinability. 303 and 304 stainless steel lead screws and flanges have good corrosion resistance.
360 brass nuts have excellent machinability and good corrosion resistance. 932 bearing bronze and 673 bronze nuts are wear resistant. They have good machinability and fair corrosion resistance. PET plastic nuts are lightweight and corrosion resistant.
Travel distance per turn, also known as screw lead, is the distance a nut moves with one revolution of the lead screw.

Combine externally threaded nuts with a flange to create a custom flange nut.
External Thread | ||||||||||||||
---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
Thread Type | Thread Size | Lg. | Dia. | No. of Thread Starts | Speed Ratio | Travel Distance per Turn | Size | Lg. | Thread Fit | Hardness | Dynamic Thrust Load Cap., lbs. | Temperature Range, °F | Each | |
360 Brass | ||||||||||||||
Acme | 1/4"-16 | 5/8" | 0.688" | 4 | 4:1 | 0.25" | 9/16"-18 | 3/8" | Class 2C | Brinell 70 | 300 | __ | 000000000 | 000000 |
673 Bronze | ||||||||||||||
Acme | 3/8"-12 | 5/8" | 0.688" | 2 | 2:1 | 0.167" | 9/16"-18 | 3/8" | Class 2C | Brinell 70 | Not Rated | __ | 000000000 | 00000 |
Stub Acme | 1/4"-12 | 5/8" | 0.688" | 4 | 4:1 | 0.333" | 9/16"-18 | 3/8" | Class 2C | Brinell 70 | Not Rated | __ | 000000000 | 00000 |
Stub Acme | 3/8"-8 | 5/8" | 0.688" | 2 | 2:1 | 0.25" | 9/16"-18 | 3/8" | Class 2C | Brinell 70 | Not Rated | __ | 000000000 | 00000 |
Stub Acme | 3/8"-8 | 5/8" | 0.688" | 4 | 4:1 | 0.5" | 9/16"-18 | 3/8" | Class 2C | Brinell 70 | Not Rated | __ | 000000000 | 00000 |
Stub Acme | 3/8"-10 | 5/8" | 0.688" | 2 | 2:1 | 0.2" | 9/16"-18 | 3/8" | Class 2C | Brinell 70 | Not Rated | __ | 000000000 | 00000 |
PET Plastic | ||||||||||||||
Acme | 1/4"-12 | 5/8" | 0.688" | 4 | 4:1 | 0.333" | 9/16"-18 | 3/8" | Class 2C | Not Rated | 160 | 15° to 175° | 000000000 | 00000 |
Acme | 3/8"-5 | 5/8" | 0.688" | 5 | 5:1 | 1" | 9/16"-18 | 3/8" | Class 2C | Not Rated | 250 | 15° to 175° | 000000000 | 00000 |
Acme | 3/8"-8 | 5/8" | 0.688" | 2 | 2:1 | 0.25" | 9/16"-18 | 3/8" | Class 2C | Not Rated | 350 | 15° to 175° | 000000000 | 00000 |
Acme | 3/8"-8 | 5/8" | 0.688" | 4 | 4:1 | 0.5" | 9/16"-18 | 3/8" | Class 2C | Not Rated | 350 | 15° to 175° | 000000000 | 00000 |
Acme | 3/8"-10 | 5/8" | 0.688" | 2 | 2:1 | 0.2" | 9/16"-18 | 3/8" | Class 2C | Not Rated | 350 | 15° to 175° | 000000000 | 00000 |

Combine externally threaded nuts with a flange to create a custom flange nut.
External Thread | |||||||||||||
---|---|---|---|---|---|---|---|---|---|---|---|---|---|
Thread Type | Thread Size | Lg. | Dia. | No. of Thread Starts | Speed Ratio | Travel Distance per Turn | Size | Lg. | Thread Fit | Hardness | Dynamic Thrust Load Cap., lbs. | Each | |
673 Bronze | |||||||||||||
Acme | 3/8"-12 | 5/8" | 0.688" | 2 | 2:1 | 0.167" | 9/16"-18 | 3/8" | Class 2C | Brinell 70 | Not Rated | 000000000 | 000000 |


Thread onto an externally threaded acme nut to create a custom flange nut.
Carbon steel flanges have good machinability. However, they will rust when exposed to moisture. Black-oxide carbon steel flanges have mild corrosion resistance in dry environments and a dark surface color. 303 stainless steel flanges have good corrosion resistance.
Metric Precision Lead Screws and Nuts

Pair with a motor in automated motion and positioning applications. A tight thread fit allows these lead screws and nuts to make accurate, repeatable starts and stops. Also known as single-start and self-locking lead screws and nuts, they have a single thread that runs the length of the screw. The nut travels only when the screw turns, so your system won’t unexpectedly move when the lead screw is at rest. To ensure compatibility, select components that have the same thread direction, size, pitch, and number of thread starts.
Manganese bronze nuts have good strength and wear resistance.
Travel distance per turn, also known as screw lead, is the distance a nut moves with one revolution of the lead screw.

External Thread | |||||||||||||||
---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
Thread Size | Thread Pitch, mm | Lg. | Dia. | No. of Thread Starts | Speed Ratio | Travel Distance per Turn, mm | Size | Lg. | Thread Fit | Hardness | Tensile Strength, psi | Dynamic Thrust Load Cap., lbs. | Specifications Met | Each | |
Manganese Bronze | |||||||||||||||
M10 | 2 | 5/8" | 0.68" | 1 | 1:1 | 2 | 9/16"-18 | 3/8" | 7H | Brinell 126 | 75,000 | 670 | DIN 103 | 0000000 | 000000 |