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Edison screw lamp bases: E12, E14, E26, E27, E39, E40 thread sizes

What are the thread diameter and pitch of E26, E27, E14 and E12 light bulb bases? · Standard part · basis: Wikipedia Edison screw table (IEC 60061-1 / ANSI C81.67 values); numbers only

Also called: e26 base dimensions, e27 thread diameter, e12 candelabra base size, e26 vs e27, light bulb base sizes, lamp socket adapter dimensions

Exact dimensions. True size, with no printing tolerance added.

sizes
6 in table

Notes

  • The number after E is the thread outer diameter in mm. E26 is the US medium base, E27 the European one; E12 is the US candelabra, E14 the European small base, E39 the US mogul.
  • Pitch: E14 2.82 mm (9 threads per inch), E26 7 threads per inch (3.63 mm, computed 25.4 / 7), E27 3.62 mm, E40 6.35 mm. E12 and E39 pitch was not confirmed on a reachable page, so none is given.
  • No file: the thread profile (flank angle, root and crest radius), base length and gauge shape are not published on any page available to Xem, and a plain cylinder at the major diameter would not be the base.

Edison screw lamp bases: E12, E14, E26, E27, E39, E40 thread sizes size chart

basethread outer diameter, mmpitch
E12 candelabra12not confirmed
E14 small142.82 mm (9 per in)
E26 medium (US)267 per in = 3.63 mm
E27 medium273.62 mm
E39 mogul (US)39not confirmed
E40 goliath406.35 mm

Where the files are

Other publishers' files are linked, not hosted. "verify" = check the license at the link before commercial use.

WikipediaEdison screwwebCC BY-SA; facts only

Xem scan

File coming

No downloadable true-size file yet: the published figures do not fix the whole shape, and Xem never guesses a number. A measured scan is planned; request it and it moves up.

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Plain text: sheet.txt · JSON: /api/geometry?object=lamp-base-edison-screw

length
Schematic, not to scale.

Fits with

A19 light bulb (E26 base), isometric render of a generated part
A19 light bulb (E26 base)61.0×61.0×107.4 mm★ sheet
A21 light bulb (E26 base), isometric render of a generated part
A21 light bulb (E26 base)78×78×140 mm★ sheet
BR30 light bulb (E26 base), isometric render of a generated part
BR30 light bulb (E26 base)95.2×95.2×136.4 mm★ sheet
BR40 light bulb (E26 base), isometric render of a generated part
BR40 light bulb (E26 base)125.4×125.4×160.3 mm★ sheet
PAR30L light bulb (E26 base), isometric render of a generated part
PAR30L light bulb (E26 base)96.8×96.8×119.1 mm★ sheet
PAR38 light bulb (E26 base), isometric render of a generated part
PAR38 light bulb (E26 base)122.2×122.2×134.9 mm★ sheet
G25 light bulb (E26 base), isometric render of a generated part
G25 light bulb (E26 base)81×81×121 mm★ sheet
MR16 light bulb (GU5.3 base), isometric render of a generated part
MR16 light bulb (GU5.3 base)51×51×55 mm★ sheet
GU10 PAR16 light bulb (GU10 base), isometric render of a generated part
GU10 PAR16 light bulb (GU10 base)50.0×50.0×54.0 mm★ sheet
length
GU10 and GU5.3 (MR16) bi-pin lamp bases: pin spacing2 sizes★ sheet

Questions

What is the diameter of an E26 base?

26 mm thread outer diameter, 7 threads per inch.

Is E26 the same as E27?

No: 26 mm and 27 mm; they often screw in but are different standards.