M4 Split Lock Washer (Spring Washer), DIN 127

The M4 split lock washer (DIN 127) is 1.8 to 2.1 mm thick, with a 4.1 to 4.4 mm hole and an outside diameter of up to 7.6 mm. It sits under M4 screw heads and nuts; here as simplified STEP files.

How these parts are made, and what the levels mean: read the method

• Also searched as: M4 washer
• Model id: din127-b-m4
• Standard: DIN 127:1987 · size M4

Files

Part key	Simplified
din127-b-m4	STEP

Dimensions

Symbol	Name	min	nom	max	Modeled	Rule	Level
d1	Inside diameter	4.1		4.4	4.25	midpoint of min–max	L1
d2	Outside diameter			7.6	7.6	single limit (max), modeled at the limit	L1
b	Section width	1.4	1.5	1.6	1.5	nominal	L1
s	Section thickness	0.8	0.9	1	0.9	nominal	L1
r	Section corner radius		0.2		0.2	nominal	L1
h	Free height	1.8		2.1	1.95	midpoint of min–max	L1

Drawing

As a PDF: CC-DIN127-SZ-M4.pdf.

Goes with the M4 split lock washer

• ISO 4762 socket head cap screw in 10 lengths from 6 to 40 mm, the same size as this M4 split lock washer: M4 Socket Head Cap Screw (Allen Bolt), ISO 4762 / DIN 912
• ISO 4017 hex head screw in 9 lengths from 8 to 40 mm, the same size as this M4 split lock washer: M4 Hex Head Screw (Hex Bolt), ISO 4017
• ISO 4032 hex nut, the same size as this M4 split lock washer: M4 Hex Nut (Hexagon Nut), ISO 4032 / DIN 934

The M4 split lock washer beside the M3 and the M5

The M4 is number 4, counting from the smallest, of the 7 DIN 127 split lock washers published here, from M2 to M8.

• Inside diameter (d1): 4.1 to 4.4 mm on the M4 split lock washer, against 3.1 to 3.4 mm on the M3 and 5.1 to 5.4 mm on the M5.
• Outside diameter (d2): up to 7.6 mm on the M4 split lock washer, against up to 6.2 mm on the M3 and up to 9.2 mm on the M5.
• Section width (b): 1.5 mm on the M4 split lock washer, against 1.3 mm on the M3 and 1.8 mm on the M5.
• Section thickness (s): 0.9 mm on the M4 split lock washer, against 0.8 mm on the M3 and 1.2 mm on the M5.
• Section corner radius (r): 0.2 mm on the M4 split lock washer, the same on the M3 and the M5.
• Free height (h): 1.8 to 2.1 mm on the M4 split lock washer, against 1.6 to 1.9 mm on the M3 and 2.4 to 2.8 mm on the M5.

Other sizes

• One size smaller: M3 Split Lock Washer (Spring Washer), DIN 127, 3.1 to 3.4 mm hole, up to 6.2 mm OD.
• One size larger: M5 Split Lock Washer (Spring Washer), DIN 127, 5.1 to 5.4 mm hole, up to 9.2 mm OD.

Documents

• CC-DIN127-DS-M4.pdf: M4 datasheet: values with levels, sources
• CC-DIN127-SZ-M4.pdf: M4 drawing: this size's values on the views
• parts.json: the part record of this size (the platform contract)

Sources

fasten-it-din127, fasteners-eu-din127, fasteners-eu-din127-a-section, globalfastener-din127, globalfastener-din127-a-section. Full citations: the method page and this size's datasheet.

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