M2.5 Hex Nut (Hexagon Nut), ISO 4032 / DIN 934

The M2.5 hex nut (ISO 4032) is 5 mm across the flats and 1.75 to 2 mm high. The thread is M2.5 × 0.45; the files are simplified and threaded STEP files.

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

• Also searched as: M2.5 nut
• Equivalent standards: DIN 934 (as listed by fasteners.eu); the values here are ISO 4032's.
• Model id: iso4032-m2-5
• Standard: ISO 4032:2012 · thread M2.5 × 0.45, ISO metric coarse, right hand

Files

Part key	Simplified	Threaded
iso4032-m2-5	STEP	STEP

Dimensions

Symbol	Name	min	nom	max	Modeled	Rule	Level
P	Thread pitch		0.45		0.45	nominal	L2
c	Washer face height	0.1		0.3	0.2	midpoint of min–max	L2
da	Countersink diameter	2.5		2.9	2.7	midpoint of min–max	L2
dw	Bearing face diameter	4.1			4.1	single limit (min), modeled at the limit	L2
e	Width across corners	5.45			5.45	single limit (min), modeled at the limit	L2
m	Nut height	1.75		2	1.875	midpoint of min–max	L2
mw	Wrenching height	1.4			1.4	single limit (min), modeled at the limit	L2
s	Width across flats	4.82	5	5	4.91	midpoint of min–max	L2
beta	Chamfer angle	15		30	22.5	midpoint of min–max	L2
theta	Countersink angle	90		120	105	midpoint of min–max	L2
P	Coarse thread pitch		0.45		0.45	nominal	L1
tap_drill	Tap drill diameter		2.05		2.05	nominal	L1
d1	Basic minor diameter		2.0128606		2.0128606	nominal	L1
ch_angle	Chamfered end angle			50	50	single limit (max), modeled at the limit	L2
dh_fine	Clearance hole, fine series		2.7		2.7	nominal	L1
dh_medium	Clearance hole, medium series		2.9		2.9	nominal	L1
dh_coarse	Clearance hole, coarse series		3.1		3.1	nominal	L1

Thread and holes

• Tap drill: 2.05 mm (method: d − P), L1, sources amesweb-tap-drill, rule-tap-drill.
• Clearance hole (ISO 273): close 2.7, normal 2.9, loose 3.1 mm (L1: fine, medium and coarse series (albany-clearance, wikipedia-de-clearance)).

Drawing

As a PDF: CC-ISO4032-SZ-M2.5.pdf.

Goes with the M2.5 hex nut

• Spanner: 5 mm, the hexagon's nominal width across flats (s) in the table above.
• ISO 4762 socket head cap screw in 9 lengths from 4 to 25 mm, the same size as this M2.5 hex nut: M2.5 Socket Head Cap Screw (Allen Bolt), ISO 4762 / DIN 912
• ISO 4017 hex head screw in 8 lengths from 5 to 25 mm, the same size as this M2.5 hex nut: M2.5 Hex Head Screw (Hex Bolt), ISO 4017
• ISO 7089 flat washer, the same size as this M2.5 hex nut: M2.5 Flat Washer (Plain Washer), ISO 7089

The M2.5 hex nut beside the M2 and the M3

The M2.5 is number 2, counting from the smallest, of the 7 ISO 4032 hex nuts published here, from M2 to M8.

• Thread pitch (P): 0.45 mm on the M2.5 hex nut, against 0.4 mm on the M2 and 0.5 mm on the M3.
• Washer face height (c): 0.1 to 0.3 mm on the M2.5 hex nut, against 0.1 to 0.2 mm on the M2 and 0.15 to 0.4 mm on the M3.
• Countersink diameter (da): 2.5 to 2.9 mm on the M2.5 hex nut, against 2 to 2.3 mm on the M2 and 3 to 3.45 mm on the M3.
• Bearing face diameter (dw): at least 4.1 mm on the M2.5 hex nut, against at least 3.1 mm on the M2 and at least 4.6 mm on the M3.
• Width across corners (e): at least 5.45 mm on the M2.5 hex nut, against at least 4.32 mm on the M2 and at least 6.01 mm on the M3.
• Nut height (m): 1.75 to 2 mm on the M2.5 hex nut, against 1.35 to 1.6 mm on the M2 and 2.15 to 2.4 mm on the M3.
• Wrenching height (mw): at least 1.4 mm on the M2.5 hex nut, against at least 1.1 mm on the M2 and at least 1.7 mm on the M3.
• Width across flats (s): 5 mm on the M2.5 hex nut, against 4 mm on the M2 and 5.5 mm on the M3.

Other sizes

• One size smaller: M2 Hex Nut (Hexagon Nut), ISO 4032 / DIN 934, 4 mm across flats.
• One size larger: M3 Hex Nut (Hexagon Nut), ISO 4032 / DIN 934, 5.5 mm across flats.

Documents

• CC-ISO4032-DS-M2.5.pdf: M2.5 datasheet: values with levels, sources
• CC-ISO4032-SZ-M2.5.pdf: M2.5 drawing: this size's values on the views
• parts.json: the part record of this size (the platform contract)

Sources

albany-clearance, amesweb-iso4032, amesweb-tap-drill, fasten-it-iso4032, fasteners-eu-iso4032, iso4032-2012-sample, iso4753-2011-sample, rule-basic-minor, rule-tap-drill, wikipedia-de-clearance, wikipedia-iso261. Full citations: the method page and this size's datasheet.

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