How to Install Key-Locking Inserts
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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 Thin Wall | ||||||||||
| 2-56 | 8-32 | 1/8" | 29 | 0.137" | 2 | MS51830-101 | 000000000 | 00000 | 000000000 | 000000 |
| 4-40 | 10-32 | 11/64" | 20 | 0.164" | 2 | MS51830-102 | 000000000 | 0000 | 000000000 | 00000 |
| 6-32 | 12-28 | 11/64" | 3/16" | 0.19" | 2 | MS51830-103 | 000000000 | 0000 | 000000000 | 00000 |
| 6-32 | 1/4"-20 | 1/4" | 7/32" | 0.216" | 2 | NAS1395C06 | 000000000 | 0000 | 000000000 | 00000 |
| 8-32 | 1/4"-20 | 1/4" | 7/32" | 0.216" | 2 | NAS1394C08 | 000000000 | 0000 | 000000000 | 00000 |
| 8-32 | 1/4"-28 | 7/32" | 15/64" | 0.231" | 2 | MS51830-104 | 000000000 | 0000 | 000000000 | 00000 |
| 10-24 | 5/16"-18 | 5/16" | I | 0.276" | 2 | MS51830-105 | 000000000 | 0000 | 000000000 | 00000 |
| 1/4"-20 | 3/8"-16 | 3/8" | Q | 0.336" | 2 | MS51830-106 | 000000000 | 0000 | 000000000 | 00000 |
| 5/16"-18 | 7/16"-14 | 7/16" | X | 0.401" | 4 | MS51830-107 | 000000000 | 0000 | 000000000 | 00000 |
| 3/8"-16 | 1/2"-13 | 1/2" | 29/64" | 0.457" | 4 | MS51830-108 | 000000000 | 0000 | 000000000 | 00000 |
| 1/2"-13 | 5/8"-11 | 5/8" | 37/64" | 0.583" | 4 | MS51830-110 | 000000000 | 00000 | 000000000 | 00000 |
18-8 Stainless Steel with Thick Wall | ||||||||||
| 8-32 | 5/16"-18 | 5/16" | 17/64" | 0.276" | 2 | NAS1395C08 | 000000000 | 0000 | 000000000 | 00000 |
| 10-24 | 3/8"-16 | 5/16" | Q | 0.336" | 2 | MS51831-101 | 000000000 | 0000 | 000000000 | 00000 |
| 1/4"-20 | 7/16"-14 | 3/8" | X | 0.401" | 2 | MS51831-102 | 000000000 | 0000 | 000000000 | 00000 |
| 5/16"-18 | 1/2"-13 | 7/16" | 29/64" | 0.457" | 4 | MS51831-103 | 000000000 | 0000 | 000000000 | 00000 |
| 5/16"-18 | 9/16"-12 | 7/16" | 33/64" | 0.521" | 4 | MS51832-103 | 000000000 | 00000 | 000000000 | 00000 |
| 3/8"-16 | 9/16"-12 | 1/2" | 33/64" | 0.521" | 4 | MS51831-104 | 000000000 | 0000 | 000000000 | 00000 |
| 3/8"-16 | 5/8"-11 | 1/2" | 37/64" | 0.583" | 4 | MS51832-104 | 000000000 | 00000 | 000000000 | 00000 |
| 7/16"-14 | 9/16"-12 | 9/16" | 33/64" | 0.521" | 4 | MS51830-109 | 000000000 | 0000 | 000000000 | 00000 |
| 7/16"-14 | 5/8"-11 | 5/8" | 37/64" | 0.583" | 4 | MS51831-105 | 000000000 | 0000 | 000000000 | 00000 |
| 7/16"-14 | 11/16"-11 | 5/8" | 41/64" | 0.646" | 4 | MS51832-105 | 000000000 | 00000 | 000000000 | 00000 |
| 1/2"-13 | 11/16"-11 | 11/16" | 41/64" | 0.646" | 4 | MS51831-106 | 000000000 | 00000 | 000000000 | 00000 |
| 1/2"-13 | 13/16"-16 | 11/16" | 49/64" | 0.771" | 4 | MS51832-106 | 000000000 | 00000 | 000000000 | 00000 |
| 9/16"-12 | 7/8"-14 | 13/16" | 53/64" | 0.833" | 4 | MS51832-107 | 000000000 | 00000 | 000000000 | 00000 |
| 5/8"-11 | 7/8"-14 | 7/8" | 53/64" | 0.833" | 4 | MS51831-108 | 000000000 | 00000 | 000000000 | 00000 |
| 5/8"-11 | 1"-12 | 7/8" | 15/16" | 0.942" | 4 | MS51832-108 | 000000000 | 00000 | 000000000 | 00000 |
| 3/4"-10 | 1 1/8"-12 | 1 1/8" | 1 1/16" | 1.067" | 4 | MS51831-109 | 000000000 | 00000 | 000000000 | 000000 |
| 3/4"-10 | 1 1/4"-12 | 1 1/8" | 1 3/16" | 1.192" | 4 | MS51832-109 | 000000000 | 00000 | 000000000 | 00000 |
| 7/8"-9 | 1 1/4"-12 | 1 1/4" | 1 3/16" | 1.192" | 4 | MS51831-110 | 000000000 | 00000 | 000000000 | 000000 |
| 7/8"-9 | 1 3/8"-12 | 1 1/4" | 1 5/16" | 1.317" | 4 | MS51832-110 | 000000000 | 00000 | 000000000 | 00000 |
| 1"-8 | 1 3/8"-12 | 1 3/8" | 1 5/16" | 1.317" | 4 | MS51831-111 | 000000000 | 00000 | 000000000 | 000000 |
| 1"-8 | 1 1/2"-12 | 1 3/8" | 1 7/16" | 1.442" | 4 | MS51832-111 | 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 | ||||||||||
| 2-56 | 8-32 | 1/8" | 9/64" | 9/64" | 2 | MS51830-A101 | 000000000 | 00000 | 000000000 | 000000 |
| 4-40 | 10-32 | 0.17" | 5/32" | 5/32" | 2 | MS51830-A102 | 000000000 | 00000 | 000000000 | 00000 |
| 6-32 | 12-28 | 0.17" | 3/16" | 3/16" | 2 | MS51830-A103 | 000000000 | 00000 | 000000000 | 00000 |
| 8-32 | 1/4"-28 | 0.22" | 15/64" | 15/64" | 2 | MS51830-A104 | 000000000 | 00000 | 000000000 | 00000 |
| 10-24 | 5/16"-18 | 5/16" | 17/64" | 17/64" | 2 | MS51830-A105 | 000000000 | 0000 | 000000000 | 00000 |
| 1/4"-20 | 3/8"-16 | 3/8" | 21/64" | 21/64" | 2 | MS51830-A106 | 000000000 | 0000 | 000000000 | 00000 |
| 5/16"-18 | 7/16"-14 | 7/16" | 25/64" | 25/64" | 4 | MS51830-A107 | 000000000 | 0000 | 000000000 | 00000 |
| 3/8"-16 | 1/2"-13 | 1/2" | 29/64" | 29/64" | 4 | MS51830-A108 | 000000000 | 0000 | 000000000 | 00000 |
| 7/16"-14 | 9/16"-12 | 9/16" | 33/64" | 33/64" | 4 | MS51830-A109 | 000000000 | 0000 | 000000000 | 00000 |
| 1/2"-13 | 5/8"-11 | 5/8" | 37/64" | 37/64" | 4 | MS51830-A110 | 000000000 | 0000 | 000000000 | 00000 |
Cadmium-Plated Alloy Steel with Thick Wall | ||||||||||
| 8-32 | 5/16"-18 | 5/16" | 17/64" | 17/64" | 2 | NAS1395-08 | 000000000 | 0000 | 000000000 | 00000 |
| 10-24 | 3/8"-16 | 5/16" | 21/64" | 21/64" | 2 | MS51831-A101 | 000000000 | 0000 | 000000000 | 00000 |
| 1/4"-20 | 7/16"-14 | 3/8" | 25/64" | 25/64" | 2 | MS51831-A102 | 000000000 | 00000 | 000000000 | 00000 |
| 5/16"-18 | 1/2"-13 | 0.437" | 29/64" | 29/64" | 4 | MS51831-A103 | 000000000 | 00000 | 000000000 | 00000 |
| 3/8"-16 | 9/16"-12 | 1/2" | 33/64" | 33/64" | 4 | MS51831-A104 | 000000000 | 00000 | 000000000 | 00000 |
| 7/16"-14 | 5/8"-11 | 5/8" | 37/64" | 37/64" | 4 | MS51831-A105 | 000000000 | 0000 | 000000000 | 00000 |
| 1/2"-13 | 11/16"-11 | 11/16" | 41/64" | 41/64" | 4 | MS51831-A106 | 000000000 | 00000 | 000000000 | 00000 |
| 5/8"-11 | 7/8"-14 | 7/8" | 53/64" | 53/64" | 4 | MS51831-A108 | 000000000 | 00000 | 000000000 | 00000 |
| 3/4"-10 | 1 1/8"-12 | 1 1/8" | 1 1/16" | 1 1/16" | 4 | MS51831-A109 | 000000000 | 00000 | 000000000 | 000000 |
| 7/8"-9 | 1 1/4"-12 | 1 1/4" | 1 3/16" | 1 3/16" | 4 | MS51831-A110 | 000000000 | 00000 | 000000000 | 000000 |
| 1"-8 | 1 3/8"-12 | 1 3/8" | 1 5/16" | 1 5/16" | 4 | MS51831-A111 | 000000000 | 00000 | 000000000 | 000000 |
Cadmium-Plated Alloy Steel with Extra Thick Wall | ||||||||||
| 3/8"-16 | 5/8"-11 | 1/2" | 37/64" | 37/64" | 4 | MS51832-A104 | 000000000 | 00000 | 000000000 | 00000 |
| 1/2"-13 | 13/16"-16 | 11/16" | 49/64" | 49/64" | 4 | MS51832-A106 | 000000000 | 00000 | 000000000 | 00000 |
| 5/8"-11 | 1"-12 | 7/8" | 15/16" | 15/16" | 4 | MS51832-A108 | 000000000 | 000000 | 000000000 | 00000 |
Mil. Spec. Rivet-Mount Nuts
Create threads in hard-to-work areas—where you can’t reach the back of a workpiece, or material is too thin to be tapped. For a strong grip, these nuts have distorted threads that increase friction with bolts. Because they mount with two rivets, they won’t spin when you’re tightening screws. However, these nuts do move inside their retainers, which lets you install bolts at a slight angle; use them to align with off-center parts. All meet military guidelines for dimensions and material.
Cadmium-plated nuts resist corrosion in industrial and saltwater environments, although will lose their corrosion resistance over 450° F. The cadmium plating also adds lubricity, making these nuts easy to install.
A286 stainless steel nuts are corrosion resistant. Silver-plated stainless steel nuts withstand temperatures up to 800° F. The silver plating also adds lubricity and prevents seizing caused by friction between nuts and bolts.
Lubricated nuts thread onto bolts smoothly.
For technical drawings and 3-D models, click on a part number.
Base | Barrel | Mounting | |||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|
| Thread Size | Lg. | Wd. | Thick. | Dia. | Ht. | No. of Holes | Hole Dia. | Hole Ctr.-to-Ctr. | Specifications Met | Each | |
Steel—Unlubricated | |||||||||||
| 4-40 | 21/32" | 5/16" | 3/32" | 0.125" | 1/16" | 2 | 0.098" | 13/32" | MS21075-04N | 000000000 | 00000 |
| 6-32 | 11/16" | 11/32" | 3/32" | 0.172" | 5/64" | 2 | 0.098" | 7/16" | MS21075-06N | 000000000 | 0000 |
| 8-32 | 45/64" | 23/64" | 3/32" | 0.203" | 5/32" | 2 | 0.098" | 15/32" | MS21075-08N | 000000000 | 0000 |
Cadmium-Plated Steel—Lubricated | |||||||||||
| 4-40 | 21/32" | 5/16" | 3/32" | 0.125" | 1/16" | 2 | 0.098" | 13/32" | MS21075L04N | 000000000 | 0000 |
| 6-32 | 11/16" | 11/32" | 3/32" | 0.172" | 5/64" | 2 | 0.098" | 7/16" | MS21075L06N | 000000000 | 0000 |
| 8-32 | 45/64" | 23/64" | 3/32" | 0.203" | 5/32" | 2 | 0.098" | 15/32" | MS21075L08N | 000000000 | 0000 |
Carbon Steel—Unlubricated | |||||||||||
| 6-32 | 61/64" | 13/32" | 1/32" | 0.172" | 11/64" | 2 | 0.098" | 11/16" | MS21059-06 | 000000000 | 0000 |
| 8-32 | 61/64" | 13/32" | 1/32" | 0.203" | 7/32" | 2 | 0.098" | 11/16" | MS21059-08 | 000000000 | 0000 |
Cadmium-Plated Carbon Steel—Lubricated | |||||||||||
| 4-40 | 61/64" | 13/32" | 1/32" | 0.141" | 9/64" | 2 | 0.098" | 11/16" | MS21059L04 | 000000000 | 0000 |
| 6-32 | 61/64" | 13/32" | 1/32" | 0.172" | 11/64" | 2 | 0.098" | 11/16" | MS21059L06 | 000000000 | 0000 |
| 8-32 | 61/64" | 13/32" | 1/32" | 0.203" | 7/32" | 2 | 0.098" | 11/16" | MS21059L08 | 000000000 | 0000 |
A286 Stainless Steel—Lubricated | |||||||||||
| 4-40 | 21/32" | 5/16" | 3/32" | 0.125" | 1/16" | 2 | 0.098" | 13/32" | MS21076L04N | 000000000 | 00000 |
| 6-32 | 11/16" | 11/32" | 3/32" | 0.172" | 5/64" | 2 | 0.098" | 7/16" | MS21076L06N | 000000000 | 00000 |
| 6-32 | 61/64" | 13/32" | 1/32" | 0.172" | 11/64" | 2 | 0.098" | 11/16" | MS21060L06 | 000000000 | 00000 |
| 8-32 | 45/64" | 23/64" | 3/32" | 0.203" | 5/32" | 2 | 0.098" | 15/32" | MS21076L08N | 000000000 | 0000 |
| 8-32 | 61/64" | 13/32" | 1/32" | 0.203" | 7/32" | 2 | 0.098" | 11/16" | MS21060L08 | 000000000 | 0000 |
Silver-Plated A286 Stainless Steel—Unlubricated | |||||||||||
| 4-40 | 21/32" | 5/16" | 3/32" | 0.125" | 1/16" | 2 | 0.098" | 13/32" | MS21076-04N | 000000000 | 00000 |
| 6-32 | 61/64" | 13/32" | 1/32" | 0.172" | 11/64" | 2 | 0.098" | 11/16" | MS21060-06 | 000000000 | 0000 |
| 8-32 | 45/64" | 23/64" | 3/32" | 0.203" | 5/32" | 2 | 0.098" | 15/32" | MS21076-08N | 000000000 | 00000 |