M2.5 Thin Hex Nut (Jam Nut), ISO 4035

The M2.5 thin hex nut (ISO 4035) is 4.82 to 5 mm across the flats and 1.35 to 1.6 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
• Model id: iso4035-m2-5
• Standard: ISO 4035:2012 · thread M2.5 × 0.45, ISO metric coarse, right hand

Files

Part key	Simplified	Threaded
iso4035-m2-5	STEP	STEP

Dimensions

Symbol	Name	min	nom	max	Modeled	Rule	Level
P	Thread pitch		0.45		0.45	nominal	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	1.35		1.6	1.475	midpoint of min–max	L2
mw	Wrenching height	1.1			1.1	single limit (min), modeled at the limit	L2
s	Width across flats	4.82		5	4.91	midpoint of min–max	L2
beta	Chamfer angle	15		30	22.5	midpoint of min–max	L2
theta	Countersink angle	110		120	115	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-ISO4035-SZ-M2.5.pdf.

Goes with the M2.5 thin hex nut

• Spanner: 5 mm, the hexagon's maximum 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 thin 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 thin hex nut: M2.5 Hex Head Screw (Hex Bolt), ISO 4017
• ISO 7089 flat washer, the same size as this M2.5 thin hex nut: M2.5 Flat Washer (Plain Washer), ISO 7089

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

The M2.5 is number 2, counting from the smallest, of the 7 ISO 4035 thin hex nuts published here, from M2 to M8.

• Thread pitch (P): 0.45 mm on the M2.5 thin hex nut, against 0.4 mm on the M2 and 0.5 mm on the M3.
• Countersink diameter (da): 2.5 to 2.9 mm on the M2.5 thin 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 thin 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 thin hex nut, against at least 4.32 mm on the M2 and at least 6.01 mm on the M3.
• Nut height (m): 1.35 to 1.6 mm on the M2.5 thin hex nut, against 0.95 to 1.2 mm on the M2 and 1.55 to 1.8 mm on the M3.
• Wrenching height (mw): at least 1.1 mm on the M2.5 thin hex nut, against at least 0.8 mm on the M2 and at least 1.2 mm on the M3.
• Width across flats (s): 4.82 to 5 mm on the M2.5 thin hex nut, against 3.82 to 4 mm on the M2 and 5.32 to 5.5 mm on the M3.
• Chamfer angle (beta): 15 to 30° on the M2.5 thin hex nut, the same on the M2 and the M3.

Other sizes

• One size smaller: M2 Thin Hex Nut (Jam Nut), ISO 4035, 3.82 to 4 mm across flats.
• One size larger: M3 Thin Hex Nut (Jam Nut), ISO 4035, 5.32 to 5.5 mm across flats.

Documents

• CC-ISO4035-DS-M2.5.pdf: M2.5 datasheet: values with levels, sources
• CC-ISO4035-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-tap-drill, boltport-iso4035, engineersedge-iso4035, fasten-it-iso4035, fuller-iso4035, iso4035-2012-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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