Washers · ISO 7980 / DIN 127

M4 Spring Lock Washers

M4 Spring Lock Washers is the m4-thread variant of Spring Lock Washers manufactured to ISO 7980 / DIN 127. This page focuses on the data engineers reach for at the bench: dimensional values for the M4 size, the spanner/drive that fits, and the assembly data you need to install it.

M4 Dimensional Row (ISO 7980 / DIN 127)

For bolt size	Inner diameter d1 min (mm)	Outer diameter d2 max (mm)	Width b (mm)	Thickness s (mm)	Reference standard
M4	4.1	7.6	2.5	1.0	ISO 7980 / DIN 127

Spanner & Drive for M4 Spring Lock Washers

Drive geometry for M4 Spring Lock Washers is given by the row above; match the tool to the listed values.

Common Applications for M4 Spring Lock Washers

M4 Spring Lock Washers are commonly specified for small electronics hardware and precision assemblies.

Installation Tips for M4 Spring Lock Washers

At M4 the joint is sensitive to over-torque — use a torque-limiting driver and check the head doesn't bury into a softer counterpart.

Mating Parts for M4

A M4 flat washer pairs with a M4 bolt/screw and matching M4 nut.

When to Step Up or Down from M4

When the joint preload approaches the proof load of M4 class 8.8, step up to M5 class 8.8 (or move to M4 class 10.9). When the joint is over-specified, M3 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 (ISO 7980 / DIN 127)

For bolt size	Inner diameter d1 min (mm)	Outer diameter d2 max (mm)	Width b (mm)	Thickness s (mm)	Reference standard
M2	2.1	4.4	1.6	0.5	ISO 7980 / DIN 127
M2.5	2.6	5.1	2.0	0.6	ISO 7980 / DIN 127
M3	3.1	6.2	2.0	0.8	ISO 7980 / DIN 127
M3.5	3.6	7.0	2.5	0.8	ISO 7980 / DIN 127
M4	4.1	7.6	2.5	1.0	ISO 7980 / DIN 127
M5	5.1	9.2	3.0	1.2	ISO 7980 / DIN 127
M6	6.1	11.8	4.0	1.6	ISO 7980 / DIN 127
M7	7.1	13.1	4.0	1.6	ISO 7980 / DIN 127
M8	8.1	14.8	5.0	2.0	ISO 7980 / DIN 127
M10	10.2	18.1	6.0	2.2	ISO 7980 / DIN 127
M12	12.2	21.1	7.0	2.5	ISO 7980 / DIN 127
M14	14.2	24.1	8.0	3.0	ISO 7980 / DIN 127
M16	16.2	27.4	9.0	3.5	ISO 7980 / DIN 127
M18	18.2	29.4	9.0	3.5	ISO 7980 / DIN 127
M20	20.2	33.6	10.0	4.0	ISO 7980 / DIN 127
M22	22.5	35.9	11.0	4.0	ISO 7980 / DIN 127
M24	24.5	40.1	12.0	5.0	ISO 7980 / DIN 127
M27	27.5	44.8	12.0	5.0	ISO 7980 / DIN 127
M30	30.5	50.0	14.0	6.0	ISO 7980 / DIN 127
M36	36.5	60.0	16.0	7.0	ISO 7980 / DIN 127

Frequently Asked Questions

What clearance and tapping drill suit M4?

Use a 4.5 mm clearance hole (ISO 273 medium) for through-fixing, or a 3.3 mm tapping drill for a coarse M4 thread.

Is M4 Spring Lock Washers suitable for electronics and small mechanisms?

M4 Spring Lock Washers is in the micro range and is widely used in electronics, instrument enclosures and small precision mechanisms. Watch the over-torque margin — micro joints strip easily.

What's the typical proof load behavior of M4 class 8.8?

Micro-thread joints are sensitive to plastic deformation in the first turn under load — use a torque-limiting driver and check the bearing surface deformation on softer mating materials.

Which washer dimensions matter most for M4?

For a flat washer, the outside diameter (the bearing surface) and the thickness control how the load is spread under the head and how much elastic preload is preserved. The inside diameter must clear the bolt body but not be so large that the head bears mostly on the washer's outer rim.

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.