Threaded Inserts · DIN 8140

M20 Helical Thread Inserts Dimensions & Specifications

M20 is one of the standard coarse-thread sizes for helical thread inserts under DIN 8140. The sections below reproduce the dimensional row, list the matching tools and hole sizes, and summarize where this size is normally specified.

M20 Dimensional Row (DIN 8140)

Thread size	Pitch (mm)	Length (mm)	Drill / tap size (mm)	Free coil diameter (mm)	Reference standard	Notes
M20	2.5	30.0	20.5 (STI tap)	22.07	DIN 8140 / ISO 10130	Wire thread insert, 1.5xD length; tang break-off

Spanner & Drive for M20 Helical Thread Inserts

Drive geometry for M20 Helical Thread Inserts is given by the row above; match the tool to the listed values.

Common Applications for M20 Helical Thread Inserts

M20 Helical Thread Inserts are commonly specified for general engineering applications.

Installation Tips for M20 Helical Thread Inserts

At M20 the stretch in the bolt becomes the controlling factor — for critical joints, use angle-controlled or stretch-controlled tightening instead of pure torque.

When to Step Up or Down from M20

When the joint preload approaches the proof load of M20 class 8.8, step up to M24 class 8.8 (or move to M20 class 10.9). When the joint is over-specified, M16 often saves weight and cost without losing the safety margin.

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

Adjust the parameters in the drawing above and click "Request this configuration" to send the exact specification 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

What clearance and tapping drill suit M20?

Use a 22 mm clearance hole (ISO 273 medium) for through-fixing, or a 17.5 mm tapping drill for a coarse M20 thread.

Should M20 Helical Thread Inserts be tightened by torque or by angle?

For critical structural joints at M20, angle-controlled or stretch-controlled tightening is more repeatable than pure torque — the friction scatter at large diameters can dominate the torque signal.

What grip range is typical for M20 structural bolts?

Grip ranges are highly application-dependent at M20. As a guide, choose a length that gives at least 1× the thread diameter engagement in the nut plus 2–3 thread pitches projecting.

What is the coarse-thread pitch of M20 for Helical Thread Inserts?

For M20 the standard coarse pitch is 2.5 mm — this is the value used for Helical Thread Inserts.

How do I request a quotation?

Use the technical drawing on this page to pick the exact configuration, then submit it with the quote form. We respond within one business day.