M8 Acorn Nut (Cap Nut), DIN 1587

Across the flats an M8 acorn nut (DIN 1587) measures 13 mm, and it stands 15 mm tall on the M8 × 1.25 thread. It comes as simplified and threaded STEP files.

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

• Also searched as: M8 acorn nut
• Model id: din1587-m8
• Standard: DIN 1587:2000 · thread M8 × 1.25, ISO metric coarse, right hand

Files

Part key	Simplified	Threaded
din1587-m8	STEP	STEP

Dimensions

Symbol	Name	min	nom	max	Modeled	Rule	Level
P	Thread pitch		1.25		1.25	nominal	L1
dk	Dome diameter			12.5	12.5	single limit (max), modeled at the limit	L1
h	Overall height	14.57	15	15	15	nominal	L1
m	Hex height	6.14		6.5	6.32	midpoint of min–max	L1
mw	Wrenching height	4.91			4.91	single limit (min), modeled at the limit	L0 (min: one source)
s	Width across flats	12.73	13	13	13	nominal	L1
e	Width across corners	14.38			14.38	single limit (min), modeled at the limit	L1
r	Dome radius		6.25 ref		6.25	reference value	L1
t	Bore depth	10.65		11.35	11	midpoint of min–max	L1
x	Thread run-out			2.5	2.5	single limit (max), modeled at the limit	L1
w	Dome wall thickness	2			2	single limit (min), modeled at the limit	L1
da	Countersink diameter	8		8.75	8.375	midpoint of min–max	L0 (min, max: one source)
dw	Bearing face diameter	11.6			11.6	single limit (min), modeled at the limit	L0 (min: one source)
beta	Chamfer angle	15		30	22.5	midpoint of min–max	L0 (min, max: one source)
theta	Countersink angle		120		120	nominal	L0 (nom: one source)
P	Coarse thread pitch		1.25		1.25	nominal	L1
tap_drill	Tap drill diameter		6.75		6.75	nominal	L1
d1	Basic minor diameter		6.646835		6.646835	nominal	L1
ch_angle	Chamfered end angle			50	50	single limit (max), modeled at the limit	L2
dh_fine	Clearance hole, fine series		8.4		8.4	nominal	L1
dh_medium	Clearance hole, medium series		9		9	nominal	L1
dh_coarse	Clearance hole, coarse series		10		10	nominal	L1

Thread and holes

• Tap drill: 6.75 mm (method: d − P), L1, sources amesweb-tap-drill, rule-tap-drill.
• Clearance hole (ISO 273): close 8.4, normal 9, loose 10 mm (L1: fine, medium and coarse series (albany-clearance, wikipedia-de-clearance)).

Drawing

As a PDF: CC-DIN1587-SZ-M8.pdf.

Goes with the M8 acorn nut

• Spanner: 13 mm, the hexagon's nominal width across flats (s) in the table above.
• ISO 4762 socket head cap screw in 14 lengths from 12 to 80 mm, the same size as this M8 acorn nut: M8 Socket Head Cap Screw (Allen Bolt), ISO 4762 / DIN 912
• ISO 4017 hex head screw in 13 lengths from 16 to 80 mm, the same size as this M8 acorn nut: M8 Hex Head Screw (Hex Bolt), ISO 4017
• ISO 7089 flat washer, the same size as this M8 acorn nut: M8 Flat Washer (Plain Washer), ISO 7089

The M8 acorn nut beside the M6

The M8 is the largest of the 4 DIN 1587 acorn nuts published here, from M4 to M8.

• Thread pitch (P): 1.25 mm on the M8 acorn nut, against 1 mm on the M6.
• Dome diameter (dk): up to 12.5 mm on the M8 acorn nut, against up to 9.5 mm on the M6.
• Overall height (h): 15 mm on the M8 acorn nut, against 12 mm on the M6.
• Hex height (m): 6.14 to 6.5 mm on the M8 acorn nut, against 4.7 to 5 mm on the M6.
• Wrenching height (mw): at least 4.91 mm on the M8 acorn nut, against at least 3.76 mm on the M6.
• Width across flats (s): 13 mm on the M8 acorn nut, against 10 mm on the M6.
• Width across corners (e): at least 14.38 mm on the M8 acorn nut, against at least 11.05 mm on the M6.
• Dome radius (r): 6.25 mm (reference) on the M8 acorn nut, against 4.75 mm (reference) on the M6.

Other sizes

• One size smaller: M6 Acorn Nut (Cap Nut), DIN 1587, 10 mm across flats.

Documents

• CC-DIN1587-DS-M8.pdf: M8 datasheet: values with levels, sources
• CC-DIN1587-SZ-M8.pdf: M8 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, fasten-it-din1587, fasteners-eu-din1587, fasteners-eu-din1587-drawing, iso4753-2011-sample, rule-basic-minor, rule-iso4759-1-nut-height, rule-tap-drill, schrauben-lexikon-din1587, wikipedia-de-clearance, wikipedia-iso261. Full citations: the method page and this size's datasheet.

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