How to Install Key-Locking Inserts
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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. 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 |