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How to Install Key-Locking Inserts
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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.
Choose inserts with a thick wall for greater strength than thin-wall inserts, or to fill a large hole.
For technical drawings and 3-D models, click on a part number.


Inserts | Installation Bits | |||||||||
---|---|---|---|---|---|---|---|---|---|---|
Thread Size | For Tap Thread Size | Installed Lg. | Drill Bit Size | For Max. Hole Dia. | Drive Style | Pkg. Qty. | Pkg. | Each | ||
18-8 Stainless Steel with Thin Wall | ||||||||||
7/16"-14 | 9/16"-18 | 0.563" | 33/64" | 0.5156" | Slotted | 1 | 000000000 | 00000 | 000000000 | 00000 |
18-8 Stainless Steel with Thick Wall | ||||||||||
7/16"-14 | 5/8"-11 | 21/32" | 17/32" | 17/32" | Slotted | 1 | 000000000 | 0000 | 000000000 | 0000 |
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.
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.
To drive slotted inserts, you can use a slotted screwdriver instead of using an installation bit or a bolt and two nuts.
For technical drawings and 3-D models, click on a part number.


Inserts | ||||||||||
---|---|---|---|---|---|---|---|---|---|---|
For Tap | Installation Bits | |||||||||
Thread Size | Thread Size | Installed Lg. | Drill Bit Size | For Max. Hole Dia. | Drive Style | Pkg. Qty. | Pkg. | Each | ||
Black-Phosphate Steel with Thin Wall | ||||||||||
7/16"-14 | 9/16"-12 | 9/16" | 33/64" | 33/64" | Slotted | 5 | 000000000 | 00000 | 000000000 | 00000 |
Black-Phosphate Steel with Thick Wall | ||||||||||
7/16"-14 | 5/8"-11 | 21/32" | 17/32" | 17/32" | Slotted | 5 | 000000000 | 0000 | 000000000 | 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.
Choose inserts with a thick wall for greater strength than thin-wall inserts, or to fill a large hole.
For technical drawings and 3-D models, click on a part number.
Inserts | ||||||||||
---|---|---|---|---|---|---|---|---|---|---|
Each | Installation Tools | |||||||||
Thread Size | For Tap Thread Size | Installed Lg. | Drill Bit Size | For Max. Hole Dia. | No. of Locking Keys | 1-9 | 10-Up | Each | ||
18-8 Stainless Steel with Thin Wall | ||||||||||
7/16"-14 | 9/16"-12 | 9/16" | 33/64" | 0.516" | 4 | 000000000 | 000000 | 000000 | 000000000 | 000000 |
18-8 Stainless Steel with Thick Wall | ||||||||||
7/16"-14 | 5/8"-11 | 5/8" | 37/64" | 0.578" | 4 | 000000000 | 00000 | 00000 | 000000000 | 00000 |
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.
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 with stripped threads.
Inserts with an extra thick wall are stronger than thick- and thin-wall inserts. Use them to reduce the size of tapped holes.
For technical drawings and 3-D models, click on a part number.
Inserts | ||||||||||
---|---|---|---|---|---|---|---|---|---|---|
Each | Installation Tools | |||||||||
Thread Size | For Tap Thread Size | Installed Lg. | Drill Bit Size | For Max. Hole Dia. | No. of Locking Keys | 1-9 | 10-Up | Each | ||
Black-Phosphate Steel with Thin Wall | ||||||||||
7/16"-14 | 9/16"-12 | 9/16" | 33/64" | 33/64" | 4 | 000000000 | 00000 | 00000 | 000000000 | 000000 |
Black-Phosphate Steel with Thick Wall | ||||||||||
7/16"-14 | 5/8"-11 | 5/8" | 37/64" | 37/64" | 4 | 000000000 | 0000 | 0000 | 000000000 | 00000 |
Black-Phosphate Steel with Extra Thick Wall | ||||||||||
7/16"-14 | 3/4"-16 | 5/8" | 45/64" | 45/64" | 4 | 000000000 | 00000 | 00000 | 000000000 | 00000 |
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.
Choose inserts with a thick wall for greater strength than thin-wall inserts, or to fill a large hole.
For technical drawings and 3-D models, click on a part number.
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 | ||
303 Stainless Steel with Thick Wall | ||||||||||
7/16"-14 | 9/16"-12 | 9/16" | 33/64" | 0.521" | 4 | MS51830-109 | 000000000 | 00000 | 000000000 | 000000 |
7/16"-14 | 11/16"-11 | 5/8" | 41/64" | 0.646" | 4 | MS51832-105 | 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.
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.
For technical drawings and 3-D models, click on a part number.
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 | ||
Cadmium-Plated Alloy Steel with Thin Wall | ||||||||||
7/16"-14 | 9/16"-12 | 9/16" | 33/64" | 33/64" | 4 | MS51830-A109 | 000000000 | 00000 | 000000000 | 000000 |
Cadmium-Plated Alloy Steel with Thick Wall | ||||||||||
7/16"-14 | 5/8"-11 | 5/8" | 37/64" | 37/64" | 4 | MS51831-A105 | 000000000 | 0000 | 000000000 | 00000 |
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.
Thin-wall inserts are often used in small holes or near the edge of a workpiece.
Choose assortments with thick-wall inserts for greater strength than thin-wall inserts, or to fill a large hole.
For technical drawings and 3-D models, click on a part number.
For Tap | ||||||
---|---|---|---|---|---|---|
Includes | No. of Inserts Included | Thread Size | Drill Bit Size | For Max. Hole Dia. | Each | |
Inch | ||||||
18-8 Stainless Steel with Thin Wall | ||||||
10-24 Thread × 0.313" Installed Lg. (20 Each) 1/4"-20 Thread × 3/8" Installed Lg. (20 Each) 5/16"-18 Thread × 0.438" Installed Lg. (15 Each) 3/8"-16 Thread × 1/2" Installed Lg. (10 Each) 7/16"-14 Thread × 0.563" Installed Lg. (10 Each) 1/2"-13 Thread × 5/8" Installed Lg. (6 Each) Installation Tool | 81 | 5/16"-18 3/8"-16 7/16"-14 1/2"-13 9/16"-12 5/8"-11 | I Q X 29/64" 33/64" 37/64" | 0.272" 0.332" 0.397" 29/64" 33/64" 37/64" | 000000000 | 0000000 |
18-8 Stainless Steel with Thick Wall | ||||||
1/4"-20 Thread × 3/8" Installed Lg. (20 Each) 5/16"-18 Thread × 0.438" Installed Lg. (15 Each) 3/8"-16 Thread × 1/2" Installed Lg. (10 Each) 7/16"-14 Thread × 5/8" Installed Lg. (10 Each) 1/2"-13 Thread × 5/8" Installed Lg. (6 Each) 9/16"-12 Thread × 0.813" Installed Lg. (5 Each) 5/8"-11 Thread × 7/8" Installed Lg. (3 Each) 3/4"-10 Thread × 1 1/8" Installed Lg. (3 Each) 7/8"-9 Thread × 1 1/4" Installed Lg. (3 Each) 1"-8 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 with Thin Wall | ||||||
10-24 Thread × 0.313" Installed Lg. (20 Each) 1/4"-20 Thread × 3/8" Installed Lg. (20 Each) 5/16"-18 Thread × 0.438" Installed Lg. (15 Each) 3/8"-16 Thread × 1/2" Installed Lg. (10 Each) 7/16"-14 Thread × 0.563" Installed Lg. (10 Each) 1/2"-13 Thread × 5/8" Installed Lg. (6 Each) Installation Tool | 81 | 5/16"-18 3/8"-16 7/16"-14 1/2"-13 9/16"-12 5/8"-11 | I Q X 29/64" 33/64" 37/64" | 0.272" 0.332" 0.397" 29/64" 33/64" 37/64" | 000000000 | 000000 |
Black-Phosphate Steel with Thick Wall | ||||||
1/4"-20 Thread × 3/8" Installed Lg. (20 Each) 5/16"-18 Thread × 0.438" Installed Lg. (15 Each) 3/8"-16 Thread × 1/2" Installed Lg. (10 Each) 7/16"-14 Thread × 5/8" Installed Lg. (10 Each) 1/2"-13 Thread × 5/8" Installed Lg. (6 Each) 9/16"-12 Thread × 0.813" Installed Lg. (5 Each) 5/8"-11 Thread × 7/8" Installed Lg. (3 Each) 3/4"-10 Thread × 1 1/8" Installed Lg. (3 Each) 7/8"-9 Thread × 1 1/4" Installed Lg. (3 Each) 1"-8 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 |
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. Cadmium-plated steel inserts are stronger than stainless steel inserts.
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. Inserts with thick walls are most commonly used; they’re stronger than thin-wall inserts and are used in larger holes.
For technical drawings and 3-D models, click on a part number.
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 | ||
303 Stainless Steel with Thin Wall | ||||||||||
7/16"-14 | 9/16"-12 | 9/16" | 33/64" | 33/64" | 4 | MS51830-109L | 000000000 | 000000 | 000000000 | 000000 |
303 Stainless Steel with Thick Wall | ||||||||||
7/16"-14 | 5/8"-11 | 5/8" | 37/64" | 37/64" | 4 | MS51831-105L | 000000000 | 00000 | 000000000 | 00000 |
Cadmium-Plated Steel with Thick Wall | ||||||||||
7/16"-14 | 5/8"-11 | 5/8" | 37/64" | 37/64" | 4 | MS51831A105L | 000000000 | 00000 | 000000000 | 00000 |
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.
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.
For technical drawings and 3-D models, click on a part number.
Thread Size | For Tap Thread Size | Installed Lg. | Drill Bit Size | For Max. Hole Dia. | No. of Locking Keys | No. of Inserts Included | Each | |
18-8 Stainless Steel with Thin Wall | ||||||||
---|---|---|---|---|---|---|---|---|
7/16"-14 | 9/16"-12 | 9/16" | 33/64" | 33/64" | 4 | 6 | 000000000 | 000000 |
18-8 Stainless Steel with Thick Wall | ||||||||
7/16"-14 | 5/8"-11 | 5/8" | 37/64" | 37/64" | 4 | 6 | 000000000 | 00000 |
Black-Phosphate Steel with Thin Wall | ||||||||
7/16"-14 | 9/16"-12 | 9/16" | 33/64" | 33/64" | 4 | 6 | 000000000 | 00000 |
Black-Phosphate Steel with Thick Wall | ||||||||
7/16"-14 | 5/8"-11 | 5/8" | 37/64" | 37/64" | 4 | 6 | 000000000 | 00000 |
Steel Hex Weld Nuts



Weld these nuts to flat and uneven uncoated steel surfaces for a strong permanent hold. A collar pilot assists alignment and prevents welding spatter from getting into threads.
All nuts meet ASME B1.1 and comply with specifications for dimensional standards.
For technical drawings and 3-D models, click on a part number.
Collar | |||||||||
---|---|---|---|---|---|---|---|---|---|
Thread Size | Wd. | Ht. | Dia. | Ht. | For Hole Dia. | Specifications Met | Pkg. Qty. | Pkg. | |
Steel | |||||||||
7/16"-14 | 3/4" | 21/64" | 21/32" | 0.05" | 43/64" | ASME B1.1 | 25 | 000000000 | 000000 |
Square Weld Nuts
Square weld nuts have more weld points than hex weld nuts for a stronger hold. Weld them on flat uncoated steel surfaces. All have a collar pilot that assists alignment and prevents welding spatter from getting into threads.
Nuts that meet ASME B1.1 comply with specifications for dimensional standards.
For technical drawings and 3-D models, click on a part number.



Collar | |||||||||
---|---|---|---|---|---|---|---|---|---|
Thread Size | Wd. | Ht. | Dia. | Ht. | For Hole Dia. | Specifications Met | Pkg. Qty. | Pkg. | |
Steel | |||||||||
7/16"-14 | 3/4" | 5/16" | 21/32" | 0.063" | 43/64" | ASME B1.1 | 25 | 000000000 | 000000 |
Threaded Adapters for Pullers

Use adapters on the ends of forcing screws and face-grip puller legs when pulling shafts, bearing caps, and pinions.
For technical drawings and 3-D models, click on a part number.
Thread Size | Gender | Each | |
7/16"-14 × 5/8"-18 | Male × Female | 000000 | 000000 |