Threaded Inserts · DIN 8140 · Application guide

What Are Helical Thread Inserts Used For?

The primary duty of Helical Thread Inserts is reinforcing or repairing threads in aluminum, magnesium and plastics. Below: the sectors that specify them in volume, the checklist used to select the right size and material for the application, installation notes, and the known limits of the type. Stocked across roughly M3 to M20, they cover general to heavy-duty work.

Typical Applications for Helical Thread Inserts

The most common settings where these are specified:

Aerospace & motorsport: lightweight alloy parts needing full-strength steel threads.
Field repair: recovering a stripped thread without scrapping the part.
General machine building: fastening covers, brackets, motors and sub-assemblies on production equipment.
Maintenance & repair (MRO): a stocked size for servicing existing plant where the original fastener spec must be matched.
Fabrication & metalwork: bench and on-site assembly of steel frames, enclosures and weldments.

How to Specify Helical Thread Inserts for Your Application

Size: Match the nominal size to the mating thread or hole. This product spans M3–M20; check the full table below for the exact dimensions of each size.
Tap & length: Drill and tap to the specified STI size, and pick insert length (commonly 1.5×D or 2×D) for the load and parent material strength.
Environment: For damp, coastal or chemical exposure prefer A4/316 stainless or a suitable coating; indoors, plated steel or A2 is usually sufficient.
Standard: This product is supplied to DIN 8140. Quoting the standard on your order guarantees interchangeable dimensions between suppliers.

Installation & Assembly Practice

Drill and tap with the specified STI tap — a standard tap will not produce the correct thread for the insert.
Install to the specified depth (typically 0.25–0.5 mm below the surface) and remove the tang where the design requires it.

Common Selection Mistakes with Helical Thread Inserts

Fitting an insert into strong steel that already holds a thread — added cost for no gain.
Skipping the tang removal, which then blocks the mating screw.

Where Helical Thread Inserts Are Not the Right Choice

Not a fix for a hole that is already oversized beyond the STI tap range, and not needed in steel that already holds a thread well.

Technical Drawing

Customize the parameters below — every spec field is editable, and the drawing redraws to match the values you choose. Changing the size will snap the other fields to that size's standard values; you can then override any individual value.

Sends the selected values to the quote form below.

Request a Quote

Set the size and options in the drawing above, then send the exact configuration straight to this form.

Category Type Standard Thread size Material Finish

Dimensions & Specifications (DIN 8140)

Thread size	Pitch (mm)	Length (mm)	Drill / tap size (mm)	Free coil diameter (mm)	Reference standard	Notes
M3	0.5	4.5	3.1 (STI tap)	3.45	DIN 8140 / ISO 10130	Wire thread insert, 1.5xD length; tang break-off
M3	0.5	6.0	3.1 (STI tap)	3.45	DIN 8140 / ISO 10130	Wire thread insert, 2xD length; tang break-off
M4	0.7	6.0	4.2 (STI tap)	4.57	DIN 8140 / ISO 10130	Wire thread insert, 1.5xD length; tang break-off
M4	0.7	8.0	4.2 (STI tap)	4.57	DIN 8140 / ISO 10130	Wire thread insert, 2xD length; tang break-off
M5	0.8	7.5	5.3 (STI tap)	5.67	DIN 8140 / ISO 10130	Wire thread insert, 1.5xD length; tang break-off
M5	0.8	10.0	5.3 (STI tap)	5.67	DIN 8140 / ISO 10130	Wire thread insert, 2xD length; tang break-off
M6	1.0	9.0	6.3 (STI tap)	6.80	DIN 8140 / ISO 10130	Wire thread insert, 1.5xD length; tang break-off
M6	1.0	12.0	6.3 (STI tap)	6.80	DIN 8140 / ISO 10130	Wire thread insert, 2xD length; tang break-off
M8	1.25	12.0	8.4 (STI tap)	9.01	DIN 8140 / ISO 10130	Wire thread insert, 1.5xD length; tang break-off
M8	1.25	16.0	8.4 (STI tap)	9.01	DIN 8140 / ISO 10130	Wire thread insert, 2xD length; tang break-off
M10	1.5	15.0	10.5 (STI tap)	11.26	DIN 8140 / ISO 10130	Wire thread insert, 1.5xD length; tang break-off
M10	1.5	20.0	10.5 (STI tap)	11.26	DIN 8140 / ISO 10130	Wire thread insert, 2xD length; tang break-off
M12	1.75	18.0	12.6 (STI tap)	13.51	DIN 8140 / ISO 10130	Wire thread insert, 1.5xD length; tang break-off
M12	1.75	24.0	12.6 (STI tap)	13.51	DIN 8140 / ISO 10130	Wire thread insert, 2xD length; tang break-off
M16	2.0	24.0	16.5 (STI tap)	17.71	DIN 8140 / ISO 10130	Wire thread insert, 1.5xD length; tang break-off
M20	2.5	30.0	20.5 (STI tap)	22.07	DIN 8140 / ISO 10130	Wire thread insert, 1.5xD length; tang break-off

Frequently Asked Questions

How do I choose the right size of Helical Thread Inserts?

Match the nominal size to the mating thread or hole. This product is available from M3 to M20; the full dimension table on this page lists each size.

When should I use Helical Thread Inserts instead of tapping directly?

Use them in soft alloys, plastics or thin sections where a cut thread would strip, or to repair a stripped hole. In strong steel that already holds a thread well, they are usually unnecessary.

What material should Helical Thread Inserts be for outdoor use?

For damp, coastal or chemical environments specify A4 (316) stainless or a suitably coated steel. For indoor or dry use, A2 (304) stainless or zinc-plated steel is normally adequate.

Are Helical Thread Inserts made to a recognized standard?

Yes — they are manufactured to DIN 8140, so dimensions are interchangeable between suppliers when you quote the standard on your order.

Can I get a quote for Helical Thread Inserts in the size and material I need?

Yes. Use the technical drawing and quote form on this page to set the size and options, then send the exact configuration to our team for pricing and lead time.