Screw-in insert
Explore our high-performance screw-in inserts (self-tapping and threaded inserts) that provide durable and reliable fastening in wood, plastic, or soft metals. Backed by 28 years of experience, Juno Industries helps you select the ideal insert for your application.
What Are Screw-In Inserts?
Definition & Purpose
A screw-in insert (also called a threaded or self-tapping insert) is a metal sleeve with internal threading that is driven or screwed into a prepared hole. It provides a robust threaded anchor in materials that are too weak to hold a direct thread.
Core Functions
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Reinforces load-bearing capability
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Offers reusable and durable threaded connection
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Distributes stress over a larger contact area
Types of Screw-In Inserts Offered
Self-Tapping Inserts
These inserts cut their own mating threads while being screwed in — ideal for wood, plastics, and soft metal.
Threaded Inserts with Flange or Collar
Designed with a flange or collar to prevent over-insertion and provide better torque resistance as well as pull-out force in thrue hole applications.
Long Inserts (Extended Length)
Longer bodies for deeper engagement in thick panels or materials requiring extra anchorage.
Inserts with Slots or Holes
Selftapping slots or 3-holes allow for better embedding in the host substrate, improving grip and load transfer without applying to much stress.
Specialized Inserts
Variants for particular use cases — e.g. die cast shell bodies, hex-driven heads, or left-hand external threads for adjustable feet or casters.
How to Choose the Right Screw-In Insert
Internal Thread (Bore Thread) Selection
Match to the screw or rod you plan to insert (e.g. M4, M6, M8, M10). Make sure the thread tolerance and class suit your load and application.
Outer Diameter & Fit
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The outer diameter should match or slightly exceed the hole diameter for interference or press fit.
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Check tolerances so the insert can be driven without damaging the host material.
Insert Length & Engagement Depth
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Ensure sufficient thread engagement length (number of turns) for load strength.
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Avoid internal stress in the host material by not over-penetrating.
Material & Corrosion Resistance
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Stainless steel (e.g. A4 / 316) for harsh or marine environments
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Zinc-plated or mild steel for indoor use
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Bronze or brass to reduce galvanic corrosion or galling when mating with stainless screws
Host Material & Density Considerations
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In softwood or MDF: less pronounced outerthreads preferred
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In hardwood or dense plastics: self-tapping variants
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Avoid splitting or over-stress by selecting appropriate geometry
Installation Guide
Drill & Prepare the Hole
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Drill the hole with the diameter recommended for the outer diameter of the insert.
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Clean out debris, dust, or chips.
Insert Driving
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Use the correct drive tool (slotted, hex, thread)
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Apply steady torque and speed
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Stop when insert is flush or reaches designed depth
Testing & Final Threading
Once installed, insert a mating screw to check fit and thread alignment. Verify that the insert is stable and properly seated.
Benefits & Best Practices
Advantages
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Strong, reusable threads in weak materials
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Prevents thread wear or stripping
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Improved load distribution and joint reliability
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Robust solution in assemblies requiring disassembly / reassembly
Tips & Best Practices
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Avoid over-tightening (risk of strip out)
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Use lubrication or anti-seize when needed (especially in harsh environments)
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For high loads, consider inserts with increased contact area (flanges, slots)
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Always test with sample material before scaling to full production
Juno Industries Services & Product Support
Product Range & Custom Options
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Standard screw-in inserts (self tapping, flanged, long, slotted)
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Materials: stainless steel, zinc plated, brass, etc.
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Custom designs: special lengths, thread types, outer geometries
Sample & Minimum Order Policies
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Free sample options for testing
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Standard MOQ: 100 pcs (50 pcs for M10 sizes and more)
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Fast delivery from European stock
Technical Assistance & Consultation
Our engineering team can help with:
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Correct product selection per your material & loading needs
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Installation methods and tooling
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Material compatibility (to prevent corrosion or galling)