How to Install Key-Locking Inserts
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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 technical drawings and 3-D models, click on a part number.
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.
For technical drawings and 3-D models, click on a part number.
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.
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 | ||
18-8 Stainless Steel with Thick Wall | ||||||||||
9/16"-12 | 13/16"-16 | 13/16" | 49/64" | 0.771" | 4 | MS51831-107 | 000000000 | 000000 | 000000000 | 000000 |
18-8 Stainless Steel with Extra Thick Wall | ||||||||||
9/16"-12 | 7/8"-14 | 13/16" | 53/64" | 0.833" | 4 | MS51832-107 | 000000000 | 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.
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 Thick Wall | ||||||||||
9/16"-12 | 3/4"-16 | 13/16" | 45/64" | 45/64" | 4 | 000000000 | 00000 | 00000 | 000000000 | 000000 |
Black-Phosphate Steel with Extra Thick Wall | ||||||||||
9/16"-12 | 7/8"-14 | 13/16" | 53/64" | 53/64" | 4 | 000000000 | 00000 | 00000 | 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.
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 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 | 0000000 |
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 |
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.
For technical drawings and 3-D models, click on a part number.