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Movement comparison

4R36 vs NH36

same diameter; same height. Can NH36 replace 4R36? The known figures match. Some fit figures are still unpublished, so this verdict is not confirmed.

Sources checked · How we source numbers
Movements to scale: Seiko 4R36, TMI NH36Dial side and side section at one scale, hand holes enlarged 8:1. A Seiko 4R36: Ø 27.4, H 5.32, date 3H, crown —. B TMI NH36: Ø 27.4, H 5.32, date 3H, crown 3H (vs A: Ø 0 H 0 mm).A Ø 27.4B Ø 27.4A 5.32B 5.32SIDE · HEIGHTS ON ONE BASELINEHAND HOLES · 8:1A hand holes —B hour 1.5 · minute 0.88 · second 0.198A Seiko 4R36Ø 27.4 · H 5.32 · date 3H · crown —B TMI NH36Ø 27.4 · H 5.32 · date 3H · crown 3Hvs A: Ø 0 H 0 mm
4R36 vs NH36 to one scaleDrawing from data, not a photo · mm

Published figures

Differences are highlighted. Each number links to its source; an empty field says what is missing.

4R36 vs NH36 specification comparison
FigureASeiko 4R36BTMI NH36
Diameter27.4 mm1secondary source27.4 mm2
Casing diameterone side onlynot in the documents we read29.36 mm2
Size in lignesone side onlynot published12‴3
Height5.32 mm1secondary source5.32 mm2
Jewels244243
Beat rate21,600 bph421,600 bph3
Power reserveone side only41 h4
2 sources disagree; show every value
  • manufacturer 41 h4
  • secondary source 40, 41 h1
not published by TMI
Accuracy (maker)one side only−35 to +45 s/day5not published by TMI
Hands and functionshours, minutes, centre seconds, date, day4hours, minutes, centre seconds, date, day3
Hacking secondsYes4Yes3
Hand windingYes4Yes7
Date windowdiffers3H1secondary source3H, 6H8
Do not set the date21:00–04:00421:00–04:009
Crownone side onlynot in the documents we read3H7 · 4H10
Hand holesone side onlynot published by Seikohour 1.5 · minute 0.88 · second 0.198 mm8
Dial feetone side onlynot in the documents we read1:36, 7:338 · 1:36, 7:338
Dial centre holeone side onlynot published2.05 mm8

Can NH36 replace 4R36?

The direction matters: this checks a watch built for the first calibre with the second installed. Size alone does not prove that hands, dial, stem and case will fit.

Drop-in· not confirmed
  • =diameterSame movement diameter: 27.4 mm.
  • =heightSame height: 5.32 mm.
  • =dateDate window at 3H on both.

Not published, so not checked: hand holes for 4R36; crown position for 4R36; dial feet for 4R36.

Check the actual case, stem height and parts before ordering. Compare another pair.

Sources

Documents checked · Report a wrong number

  1. 1Grail Watch — Grail Watch Reference: Seiko Cal. 4R36 · html · read
  2. 2Time Module Ltd. — Watch Movement Specification and Drawing - Standard Mechanical Movement NH36A · pdf · read
  3. 3Time Module Ltd. — Product Line-Up - Mechanical (NH0&NH3); NH34/NH35/NH36 product blocks · html · read
  4. 4Seiko Watch Corporation — Instructions: Seiko Automatic Diver's Watch Cal. 4R15/4R16/4R35/4R36/7S26/7S35/7S36 (English) · pdf · read
  5. 5Seiko Watch Corporation — Instructions: Diver's Watch for Air Diving, Cal. 4R35 / 4R36 (English) · pdf · read
  6. 6Seiko Watch Corporation — Instructions: Mechanical watch, Cal. 4R35 / 4R36 / 4R37 / 4R38 / 4R71 / 4R72 / 4R39 (English) · pdf · read
  7. 7Time Module Ltd. — Technical Guide & Parts Catalogue, Cal.NH3 Series (NH34A/35A/36A/37A/38A/39A) - Automatic Mechanical · pdf · read
  8. 8Time Module Ltd. — Watch Movement Specification and Drawing - NH36A (drawing pages read: Hand Fitting, Hand Setting Stem, Dial, Hands) · pdf · read
  9. 9Time Module Ltd. — Operation Manual, Cal.NH3 Series (NH34A/35A/36A/37A/38A/39A) · pdf · read
  10. 10Lucius Atelier (seller) — Seiko Mod Dial Compatibility Guide: NH34, NH35, NH36 (blog article) · html · read