Key Locking Inserts

Key locking thread inserts are designed to repair damaged threads or for use in original equipment, provide easy installation and versatility, available in carbon and stainless steel, both inch and metric series, and are supplied in Miniature, Thin wall, Thick Wall and Extra Thick Wall styles.

Featuring a key-locking action that prevents rotation due to vibration or torsion.

  • Mechanical Lock Prevention: Integrated keys drive into the parent material, locking the insert firmly against rotation and vibration.
  • Industrial-Grade Durability: Available in high-strength carbon steel and stainless steel for maximum corrosion resistance.
  • Easy Installation & Repair: No special taps required. Ideal for quickly repairing stripped threads or reinforcing original equipment.
  • USA Standard Compliance: Precision-engineered to meet rigorous US industrial and manufacturing standards.
key locking thread insert drill chart

Product Variations & Sizes

Key Locking Inserts For Metal

Mil-Spec Stainless Steel Key-Locking Inserts Miniature Non-Locking

Insert Finish: Passivated

Internal Thread (D1) External Thread (D2) Length/In (L) Internal Thread Class: External Thread Class Drill bit size Part # DINAMRO Military Standard Military Standard Part# Part No MCMASTER CHRISLYNN National Aerospace Standard Part#
2-56 8-32 1/8 3B 3A 29 D130001 MS51830-101 93904A100 76283 NA
4-40 10-32 11/64 3B 2A 20 D130002 MS51830-102 93904A200 76284 NA
4-40 12-24 1/4 3B 2A 14 D130003 NAS1395C04 93904A211 NA NA
6-32 12-28 11/64 3B 2A 3/16 D130004 MS51830-103 93904A300 76285 NA
6-32 1/4-20 1/4 3B 2A 7/32 D130005 NAS1395C06 93904A212 NA NA
8-32 1/4-20 1/4 3B 2A 7/32 D130006 NAS1394C08 93904A213 NA NA
8-32 1/4-28 7/32 3B 2A 15/64 D130007 MS51830-104 93904A400 76286 NA

Mil-Spec Stainless Steel Key-Locking Inserts Thin Wall Non-Locking

Insert Finish: Passivated

Internal Thread (D1) External Thread (D2) Length/In (L) Internal Thread Class: External Thread Class Drill bit size Part # DINAMRO Military Standard Military Standard Part# Part No MCMASTER CHRISLYNN CarrLane National Aerospace Standard Part#
10-24 5/16”-18 5/16” 3B 2A I D130008 MS51830-105 93904A600 76321 CL-1024-TSKS NA
10-32 5/16”-18 5/16” 3B 2A I D130009 MS51830-201 93904A612 76521 CL-1032-TSKS NAS1394C3
1/4”-20 3/8”-16 3/8” 3B 2A Q D130010 MS51830-106 93904A610 76322 CL-1420-TSKS NA
1/4”-28 3/8”-16 3/8” 3B 2A Q D130011 MS51830-202 93904A622 76522 CL-1428-TSKS NAS1394C4
5/16”-18 7/16”-14 7/16” 3B 2A X D130012 MS51830-107 93904A620 76323 CL-51618-TSKS NA
5/16”-24 7/16”-14 7/16” 3B 2A X D130013 MS51830-203 93904A214 76523 MS51830-203
3/8”-16 1/2”-13 1/2” 3B 2A 29/64” D130014 MS51830-108 93904A630 76324 CL-3816-TSKS NA
3/8”-24 1/2”-13 1/2” 3B 2A 29/64” D130015 MS51830-204 93904A215 76524 NAS1394C5
7/16”-14 9/16”-12 9/16” 3B 2A 33/64” D130016 MS51830-109 93904A227 76325 NA
7/16”-20 9/16”-12 9/16” 3B 2A 33/64” D130017 MS51830-205 93904A216 76525 NAS1394C7
1/2”-13 5/8”-11 5/8” 3B 2A 37/64” D130018 MS51830-110 93904A640 76326 CL-1213-TSKS NA
1/2”-20 5/8”-11 5/8” 3B 2A 37/64” D130019 MS51830-206 93904A217 76526 NAS1394C8

Mil-Spec Stainless Steel Key-Locking Inserts Thick Wall Non-Locking

Insert Finish: Passivated

Internal Thread (D1) External Thread (D2) Length/In (L) Internal Thread Class: External Thread Class Drill bit size Part # DINAMRO Military Standard Military Standard Part# Part No MCMASTER CHRISLYNN CarrLane National Aerospace Standard Part#
8-32 5/16”-18 5/16” 3B 2A I D130020 NA 93904A500 76300 NAS1395C08
10-24 3/8”-16 5/16” 3B 2A Q D130021 MS51831-101 93904A510 76301 CL-1024-SKS NA
10-32 3/8”-16 5/16” 3B 2A Q D130022 MS51831-201 93904A512 76501 CL-1032-SKS NAS1395C3
1/4”-20 7/16”-14 3/8” 3B 2A X D130023 MS51831-102 93904A520 76302 CL-1420-SKS NA
1/4”-28 7/16”-14 3/8” 3B 2A X D130024 MS51831-202 93904A522 76502 CL-1428-SKS NAS1395C4
5/16”-18 1/2”-13 7/16” 3B 2A 29/64” D130025 MS51831-103 93904A530 76303 CL-51618-SKS NA
5/16”-24 1/2”-13 7/16” 3B 2A 29/64” D130026 MS51831-203 93904A532 76503 NAS1395C5
3/8”-16 9/16”-12 1/2” 3B 2A 33/64” D130027 MS51831-104 93904A540 76304 CL-3816-SKS NA
3/8”-24 9/16”-12 1/2” 3B 2A 33/64” D130028 MS51831-204 93904A542 76504 CL-3824-SKS NAS1395C6
7/16”-14 5/8”-11 5/8” 3B 2A 37/64” D130029 MS51831-105 93904A226 76305 NA
7/16”-20 5/8”-11 5/8” 3B 2A 37/64” D130030 MS51831-205 93904A229 76505 NAS1395C7
1/2”-13 11/16-11 5/8” 3B 2A 45/64” D130031 MS51831-106 93904A550 76306 NA
1/2”-20 11/16-11 5/8” 3B 2A 45/64” D130032 MS51831-206 93904A232 76506 NAS1395C8
9/16”-12 13/16″-16 13/16” 3B 2A 45/64” D130033 MS51831-107 93904A234 76307 NA
9/16”-18 13/16″-16 13/16” 3B 2A 45/64” D130034 MS51831-207 93904A236 76507 NAS1395C9
5/8”-11 7/8”-14 7/8” 3B 2A 53/64” D130035 MS51831-108 93904A238 76308 CL-5811-SKS NA
5/8”-18 7/8”-14 7/8” 3B 2A 53/64” D130036 MS51831-208 93904A241 76508 NAS1395C10
3/4”-10 1 1/8”-12 1 1/8” 3B 2A 1 1/16” D130037 MS51831-109 93904A244 76309 CL-3410-SKS NA
3/4”-16 1 1/8”-12 1 1/8” 3B 2A 1 1/16” D130038 MS51831-209 93904A245 76509 NA
7/8″-9 1 1/4”-12 1 1/4″ 3B 2A 1 3/16″ D130039 MS51831-110 93904A247 76310 NA
7/8″-14 1 1/4”-12 1 1/4″ 3B 2A 1 3/16″ D130040 MS51831-210 93904A249 76510 NA
1″-8 1 3/8”-12 1 3/8″ 3B 2A 1 5/16″ D130041 MS51831-111 93904A252 NA
1″-12 1 3/8”-12 1 3/8″ 3B 2A 1 5/16″ D130042 MS51831-211 93904A254 76511 NA

Mil-Spec Stainless Steel Key-Locking Inserts Extra Thick Wall Non-Locking

Insert Finish: Passivated

Internal Thread (D1) External Thread (D2) Length/In (L) Internal Thread Class: External Thread Class Drill bit size Part # DINAMRO Military Standard Military Standard Part# Part No MCMASTER CHRISLYNN
10-24 7/16”-14 5/16” 3B 2A X D130043 MS51832-101 93904A218 76333
10-32 7/16”-14 5/16” 3B 2A X D130044 MS51832-201 93904A219 76533
1/4”-20 1/2”-13 3/8” 3B 2A 29/64” D130045 MS51832-102 93904A313 76334
1/4”-28 1/2”-13 3/8” 3B 2A 29/64” D130046 MS51832-202 93904A221 76534
5/16”-18 9/16”-12 7/16” 3B 2A 33/64” D130047 MS51832-103 93904A222 76335
5/16”-24 9/16”-12 7/16” 3B 2A 33/64” D130048 MS51832-203 93904A223 76535
3/8”-16 5/8”-11 1/2” 3B 2A 37/64” D130049 MS51832-104 93904A224 76336
3/8”-24 5/8”-11 1/2” 3B 2A 37/64” D130050 MS51832-204 93904A225 76536
7/16”-14 11/16”-11 5/8” 3B 2A 45/64” D130051 MS51832-105 93904A228 76337
1/2”-13 13/16”-16 11/16” 3B 2A 53/64” D130052 MS51832-106 93904A231 76338
1/2”-20 13/16”-16 11/16” 3B 2A 53/64” D130053 MS51832-206 93904A233 76538
9/16”-12 7/8”-14 13/16” 3B 2A 53/64” D130054 MS51832-107 93904A235 76339
9/16”-18 7/8”-14 13/16” 3B 2A 53/64” D130055 MS51832-207 93904A237 76539
5/8”-11 1”-12 7/8” 3B 2A 15/16” D130056 MS51832-108 93904A239 76340
5/8”-18 1”-12 7/8” 3B 2A 15/16” D130057 MS51832-208 93904A242 76540
3/4”-10 1 1/4”-12 1 1/8” 3B 2A 1 3/16” D130058 MS51832-109 93904A243 76341
7/8”-9 1 3/8”-12 1 1/4” 3B 2A 1 5/16” D130059 MS51832-110 93904A248 76342
1”-8 1 1/2”-12 1 3/8” 3B 2A 1 7/16” D130060 MS51832-111 93904A253 76343

Mil-Spec Metric Stainless Steel Key-Locking Inserts Heavy Duty Non-Locking

Insert Finish: Passivated

Internal Thread (D1) External Thread (D2) Length/In (L) Internal Thread Class: External Thread Class Drill bit size Part # DINAMRO Military Standard Military Standard Part# Part No MCMASTER CHRISLYNN
M4x0.7 M 8×1.25 8.0 5H 4H 6.9 D130061 KNHM 4×0.7 NA 66363
M5x0.8 M 10×1.25 10.0 5H 4H 8.8 D130062 KNHM 5×0.8 NA 66364
M6x1.0 M 12×1.25 12.0 5H 4H 10.8 D130063 KNHM 6×1.0 NA 76365
M8x1.25 M 14X1.5 14.0 5H 4H 12.8 D130064 KNHM 8×1.25 NA 66366
M8x1.0 M 14X1.5 14.0 5H 4H 12.8 D130065 KNHM 8×1.0 NA 66566
M10x1.5 M 16×1.5 16.0 5H 4H 14.75 D130066 KNHM 10×1.5 NA 66367
M10-1.25 M 16×1.5 16.0 5H 4H 14.75 D130067 KNHM 10×1.25 NA 66567
M12-1.75 M 18X1.5 18.0 5H 4H 16.75 D130068 KNHM 12×1.75 NA 66369
M12-1.5 M 18X1.5 18.0 5H 4H 16.75 D130069 KNHM 12×1.5 NA NA
M12-1.25 M 18X1.5 18.0 5H 4H 16.75 D130070 KNHM 12×1.25 NA 66569
M 14×2.0 M 20×1.5 20.0 5H 4H 18.75 D130071 KNHM 14×2.0 NA 66370
M 14×1.5 M 20×1.5 20.0 5H 4H 18.75 D130072 KNHM 14×1.5 NA 66570
M 16×2.0 M 22×1.5 22.0 5H 4H 20.5 D130073 KNHM16x2.0 NA 76371
M 16×1.5 M 22×1.5 22.0 5H 4H 20.5 D130074 KNHM 16×1.5 NA 76571
M 18×1.5 M 24×1.5 24.0 5H 4H 22.5 D130075 KNHM 18×1.5 NA 66572
M 20×2.5 M 30×2.0 30.0 5H 4H 28.0 D130076 KNHM 20×2.5 NA 76373
M 20×1.5 M 30×2.0 30.0 5H 4H 28.0 D130077 KNHM 20×1.5 NA 66573
M 22×1.5 M 32×2.0 32.0 5H 4H 30.0 D130078 KNHM 22×1.5 NA 76574
M 24×3.0 M 33×2.0 33.0 5H 4H 31.0 D130079 KNHM 24×3.0 NA 66375
M 24×2.0 M 33×2.0 33.0 5H 4H 31.0 D130080 KNHM 24×2.0 NA 76575

Mil-Spec Metric Stainless Steel Key-Locking Inserts Thin Wall Non-Locking

Insert Finish: Passivated

Internal Thread (D1) External Thread (D2) Length/In (L) Internal Thread Class: External Thread Class Drill bit size Part # DINAMRO Military Standard Military Standard Part# Part No MCMASTER CHRISLYNN
M 5×0.8 M 8×1.25 8.0 5H 4H 6.9 D130081 KNM 5×0.8 NA 76351
M 6×1.0 M 10×1.25 10.0 5H 4H 8.8 D130082 KNM 6×1.0 NA 76352
M 8×1.25 M 12×1.25 12.0 5H 4H 10.8 D130083 KNM 8×1.25 NA 76353
M 8×1.0 M 12×1.25 12.0 5H 4H 10.8 D130084 KNM 8×1.0 NA 76553
M 10×1.5 M 14X1.5 14.0 5H 4H 12.8 D130085 KNM 10×1.5 NA 76355
M 10×1.25 M 14X1.5 14.0 5H 4H 12.8 D130086 KNM 10×1.25 NA 76555
M 12×1.75 M 16X1.5 16.0 5H 4H 14.75 D130087 KNM 12×1.75 NA 76356
M 12×1.25 M 16X1.5 16.0 5H 4H 14.75 D130088 KNM 12×1.25 NA 76556

Mil-Spec Metric Stainless Steel Key-Locking Inserts Miniature Non-Locking

Insert Finish: Passivated

Internal Thread (D1) External Thread (D2) Length/In (L) Internal Thread Class: External Thread Class Drill bit size Part # DINAMRO Military Standard Military Standard Part# Part No MCMASTER CHRISLYNN
M2 x 0.4 M4 x 0.7 3 5H 4H 6.9 D130089 KNCM 2×0.4 NA 76382
M2.5 x 0.45 M4.5 x 0.75 3.81 5H 4H 8.8 D130090 KNCM 2.5×0.45 NA 76383
M3 x 0.5 M5 x 0.8 4.25 5H 4H 10.8 D130091 KNCM 3×0.5 NA 76384
M4 x 0.7 M6 x 0.75 5.25 5H 4H 10.8 D130092 KNCM 4×0.7 NA 76386

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