M8 Wing Nut (Butterfly Nut), DIN 315

The M8 wing nut (DIN 315) spans 36 to 39 mm across its wings and 18 to 20 mm high. The thread is M8 × 1.25; the files are simplified and threaded STEP files.

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

• Also searched as: M8 wing nut
• Model id: din315-m8
• Standard: DIN 315:1998 · thread M8 × 1.25, ISO metric coarse, right hand

Files

Part key	Simplified	Threaded
din315-m8	STEP	STEP

Dimensions

Symbol	Name	min	nom	max	Modeled	Rule	Level
P	Thread pitch		1.25		1.25	nominal	L1
d2	Boss diameter at the bearing face	13		16	14.5	midpoint of min–max	L1
d3	Boss diameter at the top	10.5		12.5	11.5	midpoint of min–max	L1
e	Wing span	36		39	37.5	midpoint of min–max	L1
g1	Wing thickness at the tip	2		2.8	2.4	midpoint of min–max	L1
g2	Wing thickness at the root	3.6		4.4	4	midpoint of min–max	L1
h	Overall height	18		20	19	midpoint of min–max	L1
m	Boss height	6.5		10	8.25	midpoint of min–max	L1
r1	Wing lobe radius		6 ref		6	reference value	L1
r3	Wing root fillet radius (front view)		1 ref		1	reference value	L1
r4	Wing root fillet radius (plan view)		3 ref		3	reference value	L1
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-DIN315-SZ-M8.pdf.

The M8 wing nut beside the M6

The M8 is the largest of the 4 DIN 315 wing nuts published here, from M4 to M8.

• Thread pitch (P): 1.25 mm on the M8 wing nut, against 1 mm on the M6.
• Boss diameter at the bearing face (d2): 13 to 16 mm on the M8 wing nut, against 10 to 13 mm on the M6.
• Boss diameter at the top (d3): 10.5 to 12.5 mm on the M8 wing nut, against 9 to 11 mm on the M6.
• Wing span (e): 36 to 39 mm on the M8 wing nut, against 30 to 33 mm on the M6.
• Wing thickness at the tip (g1): 2 to 2.8 mm on the M8 wing nut, against 1.5 to 2.3 mm on the M6.
• Wing thickness at the root (g2): 3.6 to 4.4 mm on the M8 wing nut, against 2.7 to 3.3 mm on the M6.
• Overall height (h): 18 to 20 mm on the M8 wing nut, against 15 to 17 mm on the M6.
• Boss height (m): 6.5 to 10 mm on the M8 wing nut, against 5 to 8 mm on the M6.

Other sizes

• One size smaller: M6 Wing Nut (Butterfly Nut), DIN 315, 30 to 33 mm across the wings.

Documents

• CC-DIN315-DS-M8.pdf: M8 datasheet: values with levels, sources
• CC-DIN315-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-din315, fasteners-eu-din315, iso4753-2011-sample, krepcom-din315, 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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