Send a part number, a photo, or a whole BOM — we supply it and stand behind it. Worldwide shipping to 80+ countries.

3G Electric
RFQ CartGet a QuoteSign inSign up
APPROVED VENDOR Key Locking Insert: Heavy Wall, 4 Keys, 5/16"-24 Int Thrd Sz, 1/2"-13 Ext Thrd Sz - Mil. Spec. Key-Locking Inserts
APPROVED VENDORMil. Spec. Key-Locking Inserts

APPROVED VENDOR Key Locking Insert: Heavy Wall, 4 Keys, 5/16"-24 Int Thrd Sz, 1/2"-13 Ext Thrd Sz

The APPROVED VENDOR Key Locking Insert is a heavy-wall, mil-spec insert with 4 keys, 5/16"-24 internal thread size, and 1/2"-13 external thread size. It is plain finish, 18-8 material, inch system, meeting…

SKU 3G-OTH-531734

Brand
APPROVED VENDOR
Item
Key Locking Insert: Heavy Wall, 4 Keys, 5/16"-24 Int Thrd Sz, 1/2"-13 Ext Thrd Sz
Category
Mil. Spec. Key-Locking Inserts
Available to Order
Trade pricing by quote — replies within 24h
Qty
WhatsApp an engineer
No account needed — your quote request goes straight to our engineers. A free account lets you track quotes and re-order faster.
Worldwide Shipping
Air & sea freight
Datasheet on Request
Technical specs
1-Day Quote
Replies within 24h

Technical Specifications

APPROVED VENDOR
Manufacturer Part Number
217-077503
Type
Plain, 10 PK
Keys
4
Wall Type
Heavy Wall
Ext Thrd Sz
1/2"-13
Finish Type
Plain
Int Thrd Sz
5/16"-24
Thread Type
Coarse
Industry Standards
MS51831-104L
Compatible Tap Size
1/2"-13
External Thread Fit
2A
Internal Thread Fit
3B
Material Grade/Class
18-8
System of Measurement
Inch
View Full Spec Sheet

Technical Documents

No technical documents available for this product.
Request documentation →
Not sure this is the right part? Get a recommendation.

Need installation or engineering help?

Installation, commissioning, maintenance plans, system design, and bundled product + service quotes — one team handles the full scope.
Talk to an engineer

Ask a question

APPROVED VENDOR Products
3G Electric (S) Pte. Ltd. — Singapore

Product Description

The APPROVED VENDOR Key Locking Insert is a heavy-wall, mil-spec insert with 4 keys, 5/16"-24 internal thread size, and 1/2"-13 external thread size. It is plain finish, 18-8 material, inch system, meeting MS51831-104L, supplied in a 10-pack.

Frequently Asked Questions

What is an APPROVED VENDOR Key Locking Insert used for?

This heavy-wall key locking insert repairs or strengthens stripped threads in metal assemblies. It is used across aerospace, defense, and industrial maintenance applications where a mil-spec (MS51831-104L) thread repair is required. The 4 keys lock the insert in place to prevent rotation under vibration.

What are the specifications of the APPROVED VENDOR Key Locking Insert 217-077503?

This insert has a 5/16"-24 internal thread and 1/2"-13 external thread, heavy wall, plain finish, 18-8 stainless steel, inch system. It includes 4 keys, meets MS51831-104L, and is supplied in a 10-pack. Compatible tap size is 1/2"-13 with external thread fit 2A and internal thread fit 3B.

Where to buy APPROVED VENDOR Key Locking Inserts worldwide?

3G Electric supplies APPROVED VENDOR key locking inserts to customers worldwide. We handle full logistics, customs clearance, and delivery for global orders. Contact us to source this MS51831-104L heavy-wall insert in a 10-pack or other quantities for your industrial thread repair needs.

How to install a key locking insert?

Installation requires drilling out the damaged thread to the specified tap size (1/2"-13 for this insert), tapping the hole, then threading the insert in using a driver tool. The 4 keys are then set into the parent material to lock the insert. Follow standard mil-spec installation procedures for best results.

Used in

Common applications for APPROVED VENDOR
Laboratory sampling — APPROVED VENDOR clear wide mouth glass bottles for collecting and storing liquid samples in non-sterile environments.
Steam heating maintenance — APPROVED VENDOR forged brass radiator valves for regulating steam flow in commercial building heating systems.
High-pressure cleaning — APPROVED VENDOR turbo spray nozzles for pressure washers used in industrial equipment cleaning up to 6,000 psi.
Cleanroom operations — APPROVED VENDOR vinyl task chairs for seating in ISO 5 classified manufacturing or assembly areas.
General sealing — APPROVED VENDOR natural rubber stoppers for closing laboratory flasks or test tubes in educational or research settings.
Tamper-evident security — APPROVED VENDOR brass lead and wire seals for securing utility meters, cargo containers, or access panels.

APPROVED VENDOR Products

3G Electric supplies APPROVED VENDOR mil. spec. key-locking inserts. We supply genuine products with in-stock availability on common SKUs, technical documentation, commissioning support, and warranty service — worldwide.

You might also need

Burners & Combustion →Pumps & Compressors →Spare Parts →All Products →

More from APPROVED VENDOR

View all APPROVED VENDOR parts →
Key Locking Insert: Thin Wall, 4 Keys, M10x1.5 Int Thrd Sz, M14x1.5 Ext Thrd Sz, Plain, Plain, 10 PK (MPN 217-077355). Key specifications — Wall Type: Thin Wall; Brand: APPROVED VENDOR; Compatible Tap Size: M14x1.5; External Thread Fit: 2A; Internal Thread Fit: 3B; Material Grade/Class: 18-8; Industry Standards: Fed Std. H28/21, MJ Form; System of Measurement: Metric.
APPROVED VENDOR
Key Locking Insert: Thin Wall, 4 Keys, M10x1.5 Int Thrd Sz, M14x1.5 Ext Thrd Sz, Plain, Plain, 10 PK (MPN 217-077355). Key specifications — Wall Type: Thin Wall; Brand: APPROVED VENDOR; Compatible Tap Size: M14x1.5; External Thread Fit: 2A; Internal Thread Fit: 3B; Material Grade/Class: 18-8; Industry Standards: Fed Std. H28/21, MJ Form; System of Measurement: Metric.
Key Locking Insert: Thin Wall, 2 Keys, #4-40 Int Thrd Sz, #10-32 Ext Thrd Sz, Stainless Steel, 10 PK (MPN 217-076284). Key specifications — Wall Type: Thin Wall; Brand: APPROVED VENDOR; Compatible Tap Size: #10-32; External Thread Fit: 2A; Internal Thread Fit: 3B; Material Grade/Class: 18-8; Industry Standards: MS51830-102; System of Measurement: Inch.
APPROVED VENDOR
Key Locking Insert: Thin Wall, 2 Keys, #4-40 Int Thrd Sz, #10-32 Ext Thrd Sz, Stainless Steel, 10 PK (MPN 217-076284). Key specifications — Wall Type: Thin Wall; Brand: APPROVED VENDOR; Compatible Tap Size: #10-32; External Thread Fit: 2A; Internal Thread Fit: 3B; Material Grade/Class: 18-8; Industry Standards: MS51830-102; System of Measurement: Inch.
Key Locking Insert: Thin Wall, 4 Keys, M6-1.00 Int Thrd Sz, M10x1.25 Ext Thrd Sz, Plain, 10 PK (MPN 217-076352). Key specifications — Wall Type: Thin Wall; Brand: APPROVED VENDOR; Compatible Tap Size: M10x1.25; External Thread Fit: 2A; Internal Thread Fit: 3B; Material Grade/Class: 18-8; Industry Standards: Fed Std. H28/21, MJ Form; System of Measurement: Metric.
APPROVED VENDOR
Key Locking Insert: Thin Wall, 4 Keys, M6-1.00 Int Thrd Sz, M10x1.25 Ext Thrd Sz, Plain, 10 PK (MPN 217-076352). Key specifications — Wall Type: Thin Wall; Brand: APPROVED VENDOR; Compatible Tap Size: M10x1.25; External Thread Fit: 2A; Internal Thread Fit: 3B; Material Grade/Class: 18-8; Industry Standards: Fed Std. H28/21, MJ Form; System of Measurement: Metric.
Key Locking Insert: Heavy Wall, 4 Keys, M10x1.25 Int Thrd Sz, M16x1.5 Ext Thrd Sz, Plain, 10 PK (MPN 217-077567). Key specifications — Wall Type: Heavy Wall; Brand: APPROVED VENDOR; Compatible Tap Size: M16x1.5; External Thread Fit: 2A; Internal Thread Fit: 3B; Material Grade/Class: 18-8; Industry Standards: Fed Std. H28/21, MJ Form; System of Measurement: Metric.
APPROVED VENDOR
Key Locking Insert: Heavy Wall, 4 Keys, M10x1.25 Int Thrd Sz, M16x1.5 Ext Thrd Sz, Plain, 10 PK (MPN 217-077567). Key specifications — Wall Type: Heavy Wall; Brand: APPROVED VENDOR; Compatible Tap Size: M16x1.5; External Thread Fit: 2A; Internal Thread Fit: 3B; Material Grade/Class: 18-8; Industry Standards: Fed Std. H28/21, MJ Form; System of Measurement: Metric.
Key Locking Insert: Heavy Wall, 4 Keys, 5/16"-18 Int Thrd Sz, 1/2"-13 Ext Thrd Sz, Plain, 10 PK (MPN 217-077303). Key specifications — Wall Type: Heavy Wall; Brand: APPROVED VENDOR; Compatible Tap Size: 1/2"-13; External Thread Fit: 2A; Internal Thread Fit: 3B; Material Grade/Class: 18-8; Industry Standards: MS51832-209; System of Measurement: Inch.
APPROVED VENDOR
Key Locking Insert: Heavy Wall, 4 Keys, 5/16"-18 Int Thrd Sz, 1/2"-13 Ext Thrd Sz, Plain, 10 PK (MPN 217-077303). Key specifications — Wall Type: Heavy Wall; Brand: APPROVED VENDOR; Compatible Tap Size: 1/2"-13; External Thread Fit: 2A; Internal Thread Fit: 3B; Material Grade/Class: 18-8; Industry Standards: MS51832-209; System of Measurement: Inch.
Key Locking Insert: Heavy Wall, 4 Keys, M20-2.50 Int Thrd Sz, M30-2.00 Ext Thrd Sz, Plain, 10 PK (MPN 217-077373). Key specifications — Wall Type: Heavy Wall; Brand: APPROVED VENDOR; Compatible Tap Size: M30-2.00; Drill Bit Size: 28.10 mm; External Thread Fit: 2A; External Thread Size: M30-2.00; Internal Thread Fit: 3B; Material Grade/Class: 18-8.
APPROVED VENDOR
Key Locking Insert: Heavy Wall, 4 Keys, M20-2.50 Int Thrd Sz, M30-2.00 Ext Thrd Sz, Plain, 10 PK (MPN 217-077373). Key specifications — Wall Type: Heavy Wall; Brand: APPROVED VENDOR; Compatible Tap Size: M30-2.00; Drill Bit Size: 28.10 mm; External Thread Fit: 2A; External Thread Size: M30-2.00; Internal Thread Fit: 3B; Material Grade/Class: 18-8.
Key Locking Insert: Extra Heavy Wall, 4 Keys, 3/4"-16 Int Thrd Sz, 1 1/4"-12 Ext Thrd Sz, 10 PK (MPN 217-077541). Key specifications — Wall Type: Extra Heavy Wall; Brand: APPROVED VENDOR; Compatible Tap Size: 1-1/4"-12; Drill Bit Size: 1-11/64 in; External Thread Fit: 2A; Internal Thread Fit: 3B; Material Grade/Class: 18-8; Industry Standards: MS51832-209L.
APPROVED VENDOR
Key Locking Insert: Extra Heavy Wall, 4 Keys, 3/4"-16 Int Thrd Sz, 1 1/4"-12 Ext Thrd Sz, 10 PK (MPN 217-077541). Key specifications — Wall Type: Extra Heavy Wall; Brand: APPROVED VENDOR; Compatible Tap Size: 1-1/4"-12; Drill Bit Size: 1-11/64 in; External Thread Fit: 2A; Internal Thread Fit: 3B; Material Grade/Class: 18-8; Industry Standards: MS51832-209L.
Key Locking Insert: Heavy Wall, 4 Keys, 1"-8 Int Thrd Sz, 1 3/8"-12 Ext Thrd Sz, Plain, Plain, 10 PK (MPN 217-076311). Key specifications — Wall Type: Heavy Wall; Brand: APPROVED VENDOR; Compatible Tap Size: 1-3/8"-12; Drill Bit Size: 1-19/64 in; External Thread Fit: 2A; Internal Thread Fit: 3B; Material Grade/Class: 18-8; Industry Standards: MS51831-211.
APPROVED VENDOR
Key Locking Insert: Heavy Wall, 4 Keys, 1"-8 Int Thrd Sz, 1 3/8"-12 Ext Thrd Sz, Plain, Plain, 10 PK (MPN 217-076311). Key specifications — Wall Type: Heavy Wall; Brand: APPROVED VENDOR; Compatible Tap Size: 1-3/8"-12; Drill Bit Size: 1-19/64 in; External Thread Fit: 2A; Internal Thread Fit: 3B; Material Grade/Class: 18-8; Industry Standards: MS51831-211.