NH35 NH36 Dimensions, Stem Height & Technical Data

The Seiko NH35 and NH36 are robust Japanese automatic mechanical movements widely used in modding, microbrand watches, independent watch projects, tool watches, dive watches, field watches, and affordable automatic watch production.

For watch case design, the NH35 and NH36 should not be treated as simple 27.40 mm movements with a 5.32 mm height. They are fixed internal mechanical systems with a larger practical casing envelope, a dial holding spacer relationship, stem-axis requirements, calendar-display constraints, rotor clearance requirements, hand-height dependencies, movement-retention needs, sealing constraints, and service-access requirements.

The headline dimensions identify the movement family.

They do not define the finished watch case.

A professional NH35 or NH36 case must resolve four linked engineering groups:

movement location, dial holding spacer strategy, anti-rotation, and retention
radial clearance, axial clearance, rotor clearance, caseback depth, and spacer-controlled casing diameter
stem-axis, crown and stem alignment, dial, date or day-date display, hand-height, rehaut, and crystal relationships
sealing, tolerances, assembly, inspection, prototype validation, and service access

HorologyCAD treats the NH35 / NH36 family as a benchmark movement family for robust Japanese automatic watch case design because it demonstrates a specific movement-led case-design problem:

A common, affordable, widely supported movement still requires controlled case engineering.

The NH35 and NH36 are accessible, robust, affordable, and supported by a large ecosystem of cases, dials, hands, crowns, stems, and related components. That ecosystem is valuable, but it can create false confidence. A case can appear NH-compatible and still fail if the dial holding spacer, crown axis, rotor envelope, calendar interface, movement retention, hand clearance, sealing geometry, and service access are not controlled.

This page separates two information layers:

Official / Technical Manufacturer Data

Specifications, dimensions, movement functions, spacer relationships, and technical references defined by NH-series technical documentation.

HorologyCAD Engineering Interpretation

Case-design guidance explaining how those technical references affect movement location, radial clearance, axial clearance, rotor clearance, crown and stem alignment, spacer fit, calendar positioning, hand clearance, sealing, manufacturability, assembly, serviceability, and prototype validation.

Manufacturer documentation defines the movement.

HorologyCAD explains what that movement requires from the case.

NH35 / NH36 Quick Reference

Specification	NH35	NH36
Movement family	NH3 Series	NH3 Series
Movement type	Japanese automatic mechanical	Japanese automatic mechanical
Ligne size	12 lignes class	12 lignes class
Outside movement diameter	27.40 mm	27.40 mm
Casing diameter with dial holding spacer	29.36 mm	29.36 mm
Total movement height	5.32 mm	5.32 mm
Frequency	21,600 vibrations per hour / 3 Hz	21,600 vibrations per hour / 3 Hz
Jewels	24	24
Running time	More than 41 hours	More than 41 hours
Winding	Automatic and manual winding	Automatic and manual winding
Stop seconds	Yes	Yes
Display	Central hours, minutes, seconds; date	Central hours, minutes, seconds; day and date
Rotor	Central oscillating weight	Central oscillating weight
Standard design role	Robust Japanese automatic date movement	Robust Japanese automatic day-date movement
Case-design status	Spacer and calendar dependent	Spacer and calendar dependent

Ligne Size Note

The ligne is a traditional Swiss and French watchmaking unit used to classify movement size. One ligne equals 2.2558 mm, although ligne classifications are nominal and should not be treated as controlling engineering dimensions.

For watch-case design and CAD development, use the movement’s official metric dimensions rather than the ligne classification.

For the NH35 / NH36 family, the important case-design dimensions are not the ligne label alone.

The important case-design references are:

27.40 mm outside movement diameter
29.36 mm casing diameter with dial holding spacer
5.32 mm total height
the stem-axis relationship
the dial holding spacer relationship
the calendar-display arrangement
the automatic rotor envelope

The ligne class helps identify the movement category.

It does not replace the actual metric casing dimensions.

NH35 / NH36 Quick Reference Card

The 27.40 mm outside movement diameter, 29.36 mm casing diameter with dial holding spacer, and 5.32 mm total height are important technical references.

They are not a finished case design.

The 27.40 mm dimension identifies the outside movement body.

The 29.36 mm dimension identifies the practical casing diameter with the dial holding spacer.

The 5.32 mm total height identifies the movement height, not the finished watch thickness.

Final case geometry must additionally account for:

dial holding spacer fit
locating surfaces
holder or spacer geometry
assembly clearance
anti-rotation control
movement-retention features
date or day-date display alignment
dial support
dial thickness
hand-to-crystal clearance
rotor clearance
caseback internal depth
caseback wall thickness
crown and stem alignment
crown-tube support
gasket systems
crystal retention
manufacturing variation
finishing allowance
service access

A movement dimension becomes useful only when its function within the complete watch system is understood.

NH35 / NH36 Quick Reference Card

Official Manufacturer Source

Item	Reference
Manufacturer / supplier ecosystem	TMI / Seiko Instruments NH3 Series
Calibres	NH35 / NH36
Movement family	NH3 Series
Primary source	NH3 Series technical guide and NH35 / NH36 technical references
Current HorologyCAD source status	Technical documentation identified and checked
HorologyCAD archive reference	HC-MTS-NH35-NH36

The NH3 Series technical documentation is the primary source for manufacturer-defined information on this page.

It contains information relating to:

outside movement diameter
casing diameter with dial holding spacer
total movement height
frequency
running time
jewel count
automatic winding
manual winding
stop-second device
date display
day-date display
spacer relationship
dimensional drawing
operating instructions

Where information is described as manufacturer or technical data, it should be traceable to the relevant NH3 Series documentation.

The technical document does not remove the need to inspect the exact movement and components used in the project.

Manufacturer-Document Use

The original NH3 Series technical documentation should be linked for attribution and verification where available.

Manufacturer drawings contain protected technical material. HorologyCAD should therefore not reproduce complete NH3 technical drawings without the appropriate permission.

HorologyCAD technical visuals and explanations should be:

independently created
clearly source-attributed
based on verified technical references
explanatory rather than copied
labelled according to source status

This maintains a clear distinction between:

manufacturer documentation
HorologyCAD engineering interpretation
HorologyCAD original explanatory material

Readers should consult the original technical document for the complete NH35 / NH36 specification.

Verification and Revision Notes

Item	Status
Manufacturer / supplier ecosystem	TMI / Seiko Instruments NH3 Series
Calibres	NH35 / NH36
Primary source	NH3 Series technical guide and related technical references
Initial HorologyCAD source review	22 June 2026
Manufacturer documentation audit	Completed against identified available NH3 references
Physical movement validation	Pending
Prototype validation	Pending
Page status	Manufacturer-documentation audited flagship draft

Verification Scope

The manufacturer specifications and principal case-integration relationships used on this page have been checked against identified NH3 Series technical references.

The audit covers:

headline specifications
outside movement diameter
casing diameter with dial holding spacer
total movement height
frequency
jewel count
running time
automatic winding
manual winding
stop-second device
NH35 date display
NH36 day-date display
dial holding spacer relationship
NH3 Series context

HorologyCAD guidance concerning finished cavity sizing, spacer strategy, holder strategy, radial clearance, axial clearance, anti-rotation, caseback architecture, rotor protection, sealing, tolerances, assembly, inspection, serviceability, and prototype acceptance is engineering interpretation.

It is not a universal set of manufacturer-prescribed case dimensions.

Configuration Warning

Final case geometry must be checked against:

physical calibre marking
exact NH35 or NH36 execution
current technical document
date or day-date configuration
selected hand-fitting height
dial construction
setting-stem option
dial holding spacer
holder or casing arrangement
crown and tube system
actual movement sample where practical

NH35 and NH36 share major architecture and case-fit similarities, but they are not identical at the calendar and dial-display level.

A date movement and a day-date movement must not be treated as visually or functionally identical.

NH35 / NH36 Compared With Other Common Watch Movements

The NH35 and NH36 are among the most widely used automatic movements in modern modding, microbrand, and independent watch projects.

Comparing them with alternatives such as the Miyota 9015, Miyota 8215, Sellita SW200-1, Sellita SW300-1, ETA 2824-2, and ETA 2892-A2 helps show why movement diameter, spacer-controlled casing diameter, height, stem position, rotor clearance, and calendar architecture must be considered before the external case shape is finalised.

The NH35 / NH36 family is larger in practical casing diameter and thicker than several common alternatives.

That distinction is central to the case-design problem.

The NH35 / NH36 is not a slim automatic movement.

It is a robust, accessible, spacer-dependent automatic movement family suited to thicker, practical, tool-style, dive-style, and affordable automatic watches.

NH35 / NH36 Compared With Other Common Movements

Technical Source Classification

The following hierarchy applies throughout this page.

Level A — Direct Manufacturer / Technical Specification
Level B — Manufacturer Drawing Interpretation
Level C — Execution-Dependent Manufacturer Information
Level D — HorologyCAD Engineering Interpretation
Level E — Project-Specific Validation

Level A means a value stated explicitly in NH3 Series technical documentation or official movement data.

Level B means a dimension or relationship read directly from a technical drawing.

Level C means a value or relationship that may change according to NH35 or NH36 execution, calendar arrangement, dial configuration, hand-fitting height, supplied stem, spacer, holder, or casing components.

Level D means case-design guidance developed from manufacturer information and movement-led engineering principles.

Level E means a relationship requiring confirmation through selected components, physical measurements, tolerance analysis, prototype assembly, functional testing, or production inspection.

Level D and Level E information must not be represented as official manufacturer specifications.

Manufacturer Data Register

Data item	Manufacturer / technical reference	Source class
Calibre family	NH3 Series	Level A
Calibres	NH35 / NH36	Level A
Outside movement diameter	27.40 mm	Level A / B
Casing diameter with dial holding spacer	29.36 mm	Level A / B
Total movement height	5.32 mm	Level A
Frequency	21,600 vibrations per hour / 3 Hz	Level A
Jewel count	24	Level A
Running time	More than 41 hours	Level A
Winding	Automatic and manual winding	Level A
Stop seconds	Yes	Level A
NH35 display	Central hours, minutes, seconds; date	Level A / C
NH36 display	Central hours, minutes, seconds; day and date	Level A / C
Dial holding spacer	Required casing relationship	Level A / B / C
Hand-fitting height	Execution dependent	Level C
Movement-holder strategy	Project specific	Level D / E
Finished case cavity	Project specific	Level D / E
Rotor clearance allowance	Project specific	Level D / E
Crown-tube position	Derived from movement stem axis and case datum system	Level B / D / E

Every numerical value used in released production CAD should be checked against:

applicable drawing page
document revision
exact movement execution
drawing convention
stated tolerance
physical movement sample where practical

Where a drawing is unclear, an inference should not be presented as confirmed manufacturer data.

Record Before Beginning CAD

Before developing the case, create a project-specific movement record.

Record:

manufacturer or supplier
calibre
NH35 or NH36 selection
physical movement marking
supplier
purchase date
date or day-date execution
hand-fitting-height code
dial specification
dial thickness
dial attachment
intended hand set
setting-stem option and reference
dial holding spacer
holder or movement-ring strategy
crown type
crown-tube architecture
solid or display caseback
manufacturer-document revision
physical measurements
known component deviations
CAD revision
prototype revision

A movement should not be represented only by a vague project label such as “NH case.”

The project record should identify the exact movement and component configuration around which the case is being developed.

Why NH35 / NH36 Dimensions Matter

A watch case designed around the NH35 or NH36 must begin with verified movement geometry.

The movement family defines:

internal case geometry
outside movement diameter
casing diameter with dial holding spacer
crown and stem alignment
axial-stack structure
dial-seat position
hand-clearance envelope
date or day-date display alignment
caseback and rotor clearance
movement-retention requirements
service access

Incorrect dimensional assumptions can result in:

stem and crown misalignment
dial or hand-clearance failure
date or day-date window error
rotor or caseback interference
poor movement retention
incorrect spacer fit
assembly incompatibility
unnecessary case thickness
functional failure during operation

The NH35 / NH36 family is widely used in modding, independent projects, and affordable production watches.

That popularity can make it appear easy to integrate.

It is not automatically easy.

A case can accept an NH35 visually and still fail if the spacer, crown axis, calendar interface, rotor envelope, and axial stack are not controlled.

TMI, Seiko Instruments, and the NH3 Series Context

The NH35 and NH36 belong to the broader NH3 movement series produced through the TMI and Seiko Instruments supply ecosystem.

These movements are widely used outside Seiko-branded watches and have become some of the most recognisable automatic calibres in the modding and microbrand markets.

Their popularity results from a practical combination of:

affordability
availability
robustness
automatic winding
manual winding
stop seconds
date or day-date functionality
broad parts compatibility
strong supplier familiarity
straightforward replacement economics

For independent and entry-level watch projects, the NH35 / NH36 family often becomes the default starting point because it is:

easy to source
widely documented
familiar to modders and assemblers
supported by many cases, dials, hands, crowns, and stems
robust enough for tool-style watches
inexpensive relative to many Swiss alternatives
suitable for first serious mechanical watch projects

That accessibility is useful, but it can create false confidence.

A movement being common does not mean the case can be designed casually.

The NH35 / NH36 still requires controlled spacer fit, crown alignment, rotor clearance, hand clearance, calendar positioning, movement retention, and caseback planning.

Current Calibre Status

This page covers the NH35 and NH36 movement family.

The NH35 / NH36 family remains important because it continues to appear in:

microbrand watches
independent-brand watches
Seiko modding projects
affordable automatic watches
tool-watch projects
dive-watch projects
first mechanical watch builds
replacement-case projects
technical education around robust Japanese automatic architecture
comparison with Miyota 9015 and Miyota 8215

The purpose of this page is not to present the NH35 / NH36 as a premium Swiss alternative or a slim automatic movement.

It is to provide a rigorous case-design reference for projects that actually use or study the NH35 / NH36 as a robust, accessible Japanese automatic movement family.

Movement Architecture

The NH35 and NH36 are automatic mechanical movements within the NH3 Series.

Their architecture includes:

central rotor automatic winding
manual winding
stop-second functionality
central hours
central minutes
central seconds
21,600 vibrations per hour
24 jewels
date display on NH35
day and date display on NH36
dial holding spacer relationship
robust entry-level automatic architecture

The NH35 is the date version.

The NH36 is the day-date version.

The movement family is not thin compared with movements such as the Miyota 9015, Sellita SW300-1, or ETA 2892-A2.

Its 5.32 mm total height, rotor system, dial holding spacer, and calendar requirements must be included from the beginning of the case-design process.

The case designer must coordinate:

movement body
dial holding spacer
movement cavity
automatic rotor
caseback
dial
hand stack
crystal
stem axis
crown tube
calendar display
movement retention
gasket compression

The NH35 / NH36 is robust and accessible.

The complete watch case still has to be engineered.

NH35 / NH36 Movement Architecture Diagram

Movement Family and Derivative Context

The NH35 and NH36 should be understood within the wider NH3 Series rather than as isolated movements.

Relevant related movements include:

NH35

The date-equipped movement and one of the most widely used automatic calibres in modding, independent projects, and microbrand watches.

NH36

The day-date version.

It shares the same broad dimensional architecture but introduces additional calendar and dial-opening requirements.

NH34

A related GMT movement incorporating an additional 24-hour hand.

This changes the hand stack, dial requirements, and crystal-clearance relationship.

NH37

A related movement with date and 24-hour indication.

It requires different dial-side and display planning.

NH38

A related no-date or open-heart movement depending on the exact execution.

Removing the standard date display changes the dial and calendar relationship but does not remove the need for exact case-fit validation.

NH39

A related movement with a 24-hour indication and different display requirements.

The existence of a wider movement family does not imply automatic interchangeability.

Each variant may alter:

dial layout
calendar interface
hand stack
crown-setting positions
crystal clearance
case-opening requirements

Every movement variant requires its own technical review.

Appropriate Applications and Limitations

The NH35 / NH36 family offers a practical balance of:

affordability
availability
robustness
modding ecosystem support
automatic winding
manual winding
stop seconds
date or day-date functionality
practical replacement economics
broad familiarity

It is particularly appropriate for:

dive watches
tool watches
field watches
modding projects
entry-level automatic watches
affordable microbrand watches
robust independent-watch projects
larger sports watches
cases using established dial and hand ecosystems
first mechanical watch projects

It is less naturally suited to projects centred on:

ultra-thin watches
refined slim dress watches
high-frequency movement requirements
movement prestige as a primary selling point
display-back watches where movement decoration is central
designs requiring very low case thickness
day-date projects where the dial interface is not properly controlled
cases where spacer fit is treated casually

These are application boundaries rather than defects.

The NH35 / NH36 can support a strong and honest watch.

It is not the right choice where maximum thinness, high-frequency operation, or movement prestige is the primary design objective.

From Manufacturer Data to Case Architecture

Manufacturer documentation tells the designer what the movement is.

It does not completely determine how the watch case should be built.

The case designer must still establish:

locating datums
cavity strategy
dial holding spacer strategy
holder geometry
radial clearance
anti-rotation
axial retention
stem-axis transfer
crown-tube geometry
rotor protection
caseback depth
dial support
date or day-date window coordination
hand clearance
crystal clearance
sealing
tolerances
assembly
inspection
service removal

The central HorologyCAD principle is:

A movement dimension becomes useful only when its role within the complete watch system is understood.

NH35 / NH36 Casing Envelope

The NH35 / NH36 should be treated as a three-dimensional casing system rather than a single simple cylinder.

The principal headline dimensions are:

27.40 mm outside movement diameter
29.36 mm casing diameter with dial holding spacer
5.32 mm total height

These dimensions serve different functions.

The 27.40 mm dimension identifies the outside movement body.

The 29.36 mm dimension identifies the practical casing diameter with the dial holding spacer.

The 5.32 mm dimension describes the total movement height, not the finished watch stack.

The finished case cavity should therefore not be represented as one unsupported cylindrical diameter.

The designer must determine:

which feature locates the movement
whether the dial holding spacer is the primary casing interface
which surface establishes the support plane
how the spacer interacts with the case
how the movement enters and leaves the case
how the dial and hands sit above the movement
how the rotor is protected below the movement
how the crown tube is aligned from the stem axis

The NH35 / NH36 is common, but the casing envelope still has to be interpreted as a controlled movement-to-case system.

Related engineering reference: Internal Case Geometry & Movement Cavity Sizing

NH35 / NH36 Internal Case Envelope Diagram

Movement Diameter, Spacer Diameter and Internal Case Geometry

The NH35 / NH36 has an outside movement diameter of 27.40 mm and a casing diameter of 29.36 mm with the dial holding spacer.

That distinction is fundamental.

The bare movement diameter is not always the practical case-design reference.

In many NH35 / NH36 case systems, the dial holding spacer becomes the dominant interface between the movement and the case.

The cavity must account for:

outside movement diameter
casing diameter with dial holding spacer
spacer geometry
movement-holder or support features
radial clearance
machining tolerance
finishing allowance
assembly clearance
anti-rotation strategy
movement seating
case-wall thickness
inspection limits
service access

A case that treats only the 27.40 mm bare movement diameter as the fit condition can fail when the spacer, dial support, and retention method are considered.

The movement and spacer must be located accurately without being forced into place.

The internal geometry must define:

where the movement sits
where the spacer locates
which surface acts as the primary datum
how rotation is prevented
how the movement is retained
how the stem axis is controlled
how the movement is removed during service

Related engineering reference: Internal Case Geometry & Movement Cavity Sizing

Dial Holding Spacer as a Case Interface

The dial holding spacer is one of the defining NH35 / NH36 case-design features.

The technical casing diameter of 29.36 mm includes this spacer relationship.

That means the spacer may control:

radial location
movement seating
dial support
movement-to-case relationship
assembly behaviour
anti-rotation
service removal
tolerance accumulation

The spacer should not be treated as incidental packaging.

It is part of the movement-fit architecture.

The designer must determine:

whether the supplied spacer is retained
whether a separate holder is used
which diameter locates the assembly
which shoulder controls axial position
how the spacer is prevented from shifting
how the assembly is removed without damage

The nominal 27.40 mm movement diameter and 29.36 mm casing diameter serve different engineering purposes.

Confusing them can produce an incorrect cavity and unreliable movement location.

Radial Clearance and Movement Location

Radial clearance is the controlled allowance between the locating components of the movement system and the surrounding case structure.

For the NH35 / NH36, the relevant interface may be:

bare movement to holder
dial holding spacer to case
spacer to movement holder
movement holder to case
clamp system to case

The correct allowance depends on:

spacer architecture
holder architecture
component material
machining method
surface finish
coating
dimensional tolerance
assembly method
inspection strategy
service requirements

Insufficient clearance can produce:

difficult insertion
forced seating
spacer distortion
holder interference
stem-axis displacement
dial displacement
date or day-date displacement
surface damage
dependence on hand fitting

Excessive clearance can produce:

radial movement
spacer movement
rotation
date or day-date displacement
dial movement
stem side loading
inconsistent crown feel
overdependence on clamps or the caseback

There is no responsible universal cavity addition suitable for every NH35 / NH36 case.

Clearance must be allocated to a defined interface within a defined architecture.

Related engineering reference: Radial Clearance

Anti-Rotation Control

Radial location and rotational control are separate functions.

A circular cavity may establish approximate concentricity while still permitting movement or spacer rotation.

Rotation can affect:

stem alignment
crown function
dial position
date-window alignment
day-date alignment
hand alignment
spacer loading
clamp loading
assembly consistency

Anti-rotation may be provided through:

dial holding spacer geometry
movement-holder geometry
casing clamps
keyed features
locating tabs
dedicated case geometry

The setting stem must not be treated as a structural anti-rotation pin.

The stem is an operating component.

It is not a substitute for movement retention.

Movement Height and Finished Watch Thickness

The NH35 / NH36 total height is 5.32 mm.

This makes the family thicker than several common automatic alternatives, especially the Miyota 9015, Sellita SW300-1, and ETA 2892-A2.

That does not make the NH35 / NH36 unsuitable for case design.

It means the vertical stack must be planned realistically.

Finished thickness must also account for:

movement seating
spacer or holder relationship
dial support
dial thickness
calendar-display clearance
hand-fitting height
hand-to-hand clearance
hand-to-crystal clearance
rehaut depth
crystal thickness
crystal retention
rotor clearance
caseback internal depth
caseback wall thickness
gasket compression
movement retention
manufacturing variation
finishing variation

A case designed around the 5.32 mm movement height alone will usually be incorrect.

Potential consequences include:

rotor contact
hand contact
movement compression
excessive caseback depth
tall rehaut geometry
greater finished thickness than expected
incorrect crown-axis position
compromised sealing geometry

The NH35 / NH36 often produces thicker finished watches because several vertical requirements accumulate:

movement height
spacer relationship
rotor clearance
calendar and dial-side stack
caseback structure
crystal clearance

Related engineering reference: Movement Height vs Case Thickness

Axial Stack Control

The axial stack controls the vertical relationship between:

caseback
rotor
movement
dial holding spacer
movement seat
dial
hands
rehaut
crystal

The NH35 / NH36 is often chosen for robustness, affordability, and parts availability rather than thinness.

That does not remove the need for controlled vertical architecture.

The caseback side must provide free operating space for the automatic winding system.

The dial side must provide controlled support and clearance for the dial, calendar display, hands, rehaut, and crystal.

Insufficient axial space can cause:

rotor rubbing
hand contact
dial loading
calendar interference
movement compression
caseback interference
reduced winding efficiency

Excessive uncontrolled space can cause:

movement lift
spacer movement
dial movement
stem misalignment
retention inconsistency
impact noise
variable crown operation

Axial clearance is not arbitrary empty space.

It is a controlled relationship between real surfaces and their tolerance limits.

Related engineering reference: Axial Clearance

NH35 / NH36 Axial Stack Diagram

Rotor Clearance and Caseback Architecture

The rotor occupies a moving envelope behind the movement.

The caseback cannot be developed only from the desired exterior profile.

Its internal geometry must preserve rotor clearance through:

movement seating variation
spacer position
rotor motion
rotor endshake
manufacturing tolerance
caseback deflection
gasket compression
finishing buildup
shock loading

A common beginner mistake is to assume that because NH35 / NH36 cases are widely available, rotor clearance is automatically solved.

It is not.

Every new case architecture must protect the rotor envelope independently.

Insufficient rotor clearance can cause:

rubbing
scraping noise
winding drag
audible contact
reduced winding efficiency
witness marks
wear debris
movement damage

A professional NH35 / NH36 case resolves the rotor volume before the exterior caseback profile is finalised.

The caseback must satisfy several requirements simultaneously:

rotor protection
structural stiffness
gasket support
thread or retention geometry
service access
acceptable external proportion

Related engineering reference: Rotor Clearance Requirements

Winding and Functional Behaviour

The NH35 / NH36 supports automatic and manual winding.

The crown and setting stem remain central to daily user interaction.

For the case designer, the important implications are:

the crown and stem system must permit smooth manual winding
the setting stem must remain aligned throughout operation
the crown must provide suitable access
the keyless works must not receive lateral load
the rotor must remain free to operate
the caseback must not introduce automatic-winding interference
date or day-date correction must remain clean and distinct

A case can satisfy nominal movement dimensions and still compromise winding performance through poor stem alignment, insufficient rotor clearance, spacer movement, or weak movement retention.

Stem Axis and Crown-Tube Alignment

The crown position must be derived from the movement stem axis.

It should not be selected visually and joined to the movement afterward.

The stem axis controls:

case-wall bore position
crown-tube centreline
crown seating
winding feel
setting feel
date or day-date correction
keyless-works loading
crown-gasket alignment
crown-guard geometry
case-wall material around the tube

If the crown tube is misplaced, the stem may be forced into alignment during assembly.

The watch may still operate, but the system can suffer from:

stem bending
rough winding
poor setting feel
keyless-works side load
uneven gasket compression
crown-tube wear
premature failure
visibly incorrect crown position

The movement support plane, spacer position, stem axis, case-wall bore, crown tube, and crown should be developed as one mechanical chain.

The crown is both:

a user interface
a sealing interface

Related engineering reference: Crown and Stem Alignment in Watch Cases

Stem Height and Crown-Tube Position

Stem height is one of the most important movement-led case dimensions.

For the NH35 / NH36, the stem axis must be interpreted from the relevant technical drawing convention and transferred into the case datum system correctly.

The designer must define:

movement support plane
movement seating level
spacer or holder relationship
stem centreline
case-tube bore height
crown-tube shoulder
crown seat
gasket relationship
external crown centreline
remaining structural material around the tube

Small stem-height errors can cause large practical problems.

The watch may still assemble, but:

crown operation may feel rough
the stem may drag
the keyless works may receive side load
the crown gasket may compress unevenly
the crown may sit visibly high or low

A correct NH35 / NH36 case uses the stem axis as a datum.

The exterior crown position is designed around that datum.

Related engineering reference: Stem Height to Crown Tube Position Relationship

NH35 vs NH36 Calendar Interface

The NH35 and NH36 share a closely related movement architecture, but their calendar interfaces are not identical.

The NH35 provides a date display.

The NH36 provides day and date displays.

This affects:

dial-aperture design
dial printing
movement rotation
crown-setting positions
calendar correction
visual alignment
spacer orientation
case-opening relationships

A case can fit the movement mechanically and still fail as a complete watch if the calendar display does not align correctly with the dial.

The designer must account for:

date-window position
day/date-window geometry
dial-print alignment
movement-rotation control
movement-holder accuracy
crown-setting behaviour
calendar-correction access

NH35 and NH36 should therefore not be treated as identical at the dial and calendar level simply because the main case-fitting dimensions are similar.

NH35 Date vs NH36 Day-Date Interface Diagram

Dial Interface and Dial Holding Spacer

The NH35 / NH36 dial side must be coordinated with:

movement location
dial holding spacer
dial seat
case opening
date or day-date aperture
rehaut
chapter ring
crystal
hand stack

Important dial constraints include:

dial-seat diameter
support geometry
dial thickness
dial-feet or dial-fixing compatibility
calendar-window position
movement rotational position
rehaut depth
chapter-ring clearance
hand-stack height
crystal underside clearance
visual centring

The dial holding spacer affects:

movement support
movement seating
dial-side relationship
radial fit
assembly behaviour
retention strategy

The dial is not merely a decorative disc above the movement.

It is part of the axial stack and the visible movement-location system.

If the movement or spacer shifts, the calendar display may misalign even when the movement continues to run.

Related engineering reference: Dial Integration & Case Interface

Dial Attachment

The final dial programme must confirm:

dial-feet compatibility
dial attachment method
locking geometry
engagement
dial thickness
date-disc or day-date clearance
service release method

The case should not compensate for an incorrectly specified dial.

Movement, spacer, dial, and case should be developed as one coordinated assembly.

Changes to dial thickness, attachment position, applied markers, dial construction, calendar-window design, or surface build-up may alter the axial stack or assembly process.

Hand-Fitting Heights and Crystal Clearance

The selected hand-fitting execution changes the dial-side stack.

The NH35 / NH36 case must provide clearance for:

hour hand above the dial
minute hand above the hour hand
seconds hand above the minute hand
seconds hand below the crystal
hand-fitting variation
dial-thickness variation
hand flex
shock displacement
crystal-position variation
manufacturing tolerance

A case can have correct movement diameter, spacer fit, rotor clearance, and crown alignment and still fail at the hand stack.

Possible failures include:

hour hand contacting the dial
minute hand contacting the hour hand
seconds hand contacting the minute hand
seconds hand contacting the crystal
hand tips contacting the rehaut
hand tips contacting the chapter ring
inadequate shock allowance

The highest operating hand should be treated as a dynamic upper boundary.

The crystal underside must remain clear under expected tolerance and operating conditions.

Related engineering references: Hand Stack Height and Clearance Requirements and Dial to Crystal Clearance

Detailed Hand-Height Data

The complete manufacturer hand-height and dial-side data should be made available through:

an expandable technical-reference section
a separate HorologyCAD reference table
direct consultation of the official NH3 Series drawing

The main article should identify the need to confirm the exact hand-fitting execution without overwhelming the introductory specification layer.

Movement Holder and Retention Strategy

The NH35 / NH36 must be retained securely without being:

distorted
pinched
allowed to shift
allowed to rotate
compressed by the caseback

A complete retention system should control:

radial movement
axial movement
rotation
dial alignment
spacer alignment
stem loading
shock response
service removal

Possible strategies include:

use of the dial holding spacer as part of the locating system
dedicated movement holder
movement ring
spacer ring
locating shoulders
casing clamps
combined locating and retention geometry

The correct method depends on:

case material
machining method
production quantity
assembly order
water-resistance target
dial architecture
service strategy

The movement should not be trapped accidentally between the dial side and caseback.

The caseback should not become the sole retention feature unless the full axial stack has deliberately been engineered for that role.

Retention must be controlled.

It should not depend on unknown compression.

Related engineering reference: Movement Securing Methods

Setting-Stem Removal and Service Access

A professional NH35 / NH36 case must allow the movement to be installed, tested, removed, and recased without damage.

Service access should be considered during CAD development, not after the first prototype has already been machined.

The case architecture should provide:

visible access to required release points
sufficient tool approach
adequate clearance around the movement
stable support during stem removal
controlled handling of the dial holding spacer
access to holder or retention features
a service sequence that avoids levering against finished surfaces

The release point and retention features should not be hidden behind:

an inaccessible spacer
an inaccessible holder
a case-wall obstruction
a casing clamp
a decorative internal feature
an assembly sequence that traps the movement

A case may hold the movement securely and still be poorly engineered if the movement cannot be removed safely.

Service access must be reviewed during CAD development.

Sealing and Water-Resistance Architecture

Water resistance must be integrated into the movement-led case architecture from the beginning.

The case must coordinate:

crown sealing
crown-tube alignment
caseback sealing
crystal sealing
gasket compression
thread engagement
sealing-surface finish
structural stiffness
axial-stack behaviour
service replacement

The crown is both an operating interface and a sealing interface.

A misaligned crown tube can compromise crown feel and gasket function simultaneously.

The caseback must preserve rotor clearance while also supporting:

gasket compression
sufficient wall thickness
thread or retention structure
repeatable assembly
service access

A shallow caseback may appear attractive externally but can compromise the rotor envelope or gasket behaviour if the internal architecture has not been resolved.

Water resistance is not added after movement fit is complete.

It is part of the same engineering system.

Related engineering references: Water Resistance Engineering in Watch Cases and Caseback Sealing System

Manufacturing and Tolerance Strategy

A CAD model can appear correct while remaining difficult or impossible to manufacture consistently.

The case architecture must account for:

tool access
cutter radius
bore accuracy
concentricity
flatness
perpendicularity
thread geometry
finishing removal
coating buildup
inspection method
component variation
assembly variation

Every critical interface should have:

nominal dimension
tolerance
functional purpose
inspection method

The designer should be able to explain:

what locates the movement
what locates the spacer
what retains the assembly
what prevents rotation
what controls the stem axis
what protects the rotor
what supports the dial
what positions the date or day-date display
what establishes hand clearance
what compresses each gasket
how each relationship will be inspected

If a critical feature cannot be measured or inspected, its production control is weak.

The NH35 / NH36 ecosystem is forgiving in sourcing.

It is not a substitute for tolerance control.

The objective is not to eliminate all clearance.

The objective is to allocate clearance and tolerance deliberately where mechanically required.

Related engineering references: Watch Case Tolerances and CNC Machining Constraints in Watch Cases

Manufacturing Suitability

The NH35 / NH36 family is highly suitable for practical production when the case is engineered correctly.

Use case	Suitability	Reason
CNC prototyping	Excellent	Robust, common, and well understood
Low-volume production	Excellent	Widely available and economically practical
Independent brands	Good to excellent	Strong affordable automatic option
First serious watch project	Excellent	Accessible when the case architecture is controlled
Modding projects	Excellent	Supported by a very large parts ecosystem
Tool and dive watches	Excellent	Robust architecture suits thicker cases
Thin automatic watches	Poor to moderate	5.32 mm height and spacer stack limit thinness
Haute horology context	Poor to moderate	Practical rather than prestigious or decorative

The NH35 / NH36 is accessible enough to be practical, but not so simple that case development can be casual.

It rewards disciplined engineering and exposes poor tolerance control, especially around:

spacer fit
crown alignment
rotor clearance
axial stack
calendar positioning
movement retention

Service Ecosystem and Long-Term Use

One of the strongest practical arguments for the NH35 / NH36 family is its service and parts ecosystem.

A movement intended for production use must be considered beyond the first sale.

It must be:

serviced
regulated
repaired
replaced
understood by future watchmakers

The NH35 / NH36 benefits from:

very wide availability
a large modding ecosystem
broad parts support
familiar dial and hand systems
accessible stems, holders, spacers, and crowns
practical replacement economics
a large community knowledge base
continued use across affordable and microbrand watches

Serviceability also imposes case-design requirements.

A well-resolved case should permit:

controlled stem removal
access to retention features
controlled spacer handling
holder or spacer removal
non-destructive movement extraction
caseback servicing
gasket replacement
reliable recasing
functional checks after assembly

A case that cannot be serviced cleanly is not fully engineered.

Collector and Product Perception

Collectors generally understand the NH35 / NH36 as:

robust
affordable
practical
familiar
easy to service
widely available

It does not carry Swiss prestige and is not normally considered a premium movement.

Its reputation is based on accessibility, durability, and ecosystem support.

That perception can be positive or negative depending on the finished watch.

In a weak watch, the NH35 / NH36 can feel like the cheapest possible automatic movement choice.

In a well-engineered watch, it can feel:

honest
durable
appropriate
maintainable
professionally integrated

Collectors usually judge an NH35 / NH36 watch by the complete execution.

Important factors include:

case thickness
crown feel
rotor behaviour
dial quality
water resistance
finishing
proportion
assembly quality

The movement provides a robust foundation.

The case design determines whether that foundation feels basic or well executed.

Known Weaknesses and Trade-Offs

The NH35 / NH36 is a strong movement family, but it is not suitable for every project.

Its trade-offs include:

greater thickness than slim automatics such as the Miyota 9015
lower perceived prestige than Swiss alternatives
21,600 vibrations per hour rather than 28,800 vibrations per hour
standard industrial finishing
common architecture that places more pressure on surrounding design quality
date or day-date alignment requirements
spacer relationship that can dominate case fit
tendency toward thick finished watches when the stack is not controlled

These characteristics do not make the NH35 / NH36 a poor movement.

They define where the surrounding watch must work harder.

A successful NH35 / NH36 watch should rely on:

robust case architecture
disciplined movement integration
good crown feel
controlled proportions
dial quality
finishing quality
serviceability
coherent engineering

It should not rely on movement prestige.

Relationship to NH34, NH37, NH38 and NH39

The NH35 / NH36 should not be treated as universal stand-ins for all NH3 Series movements.

Related variants may alter the dial and case-design problem.

NH34

A GMT movement with an additional 24-hour hand.

This can affect:

hand stack
crystal clearance
dial printing
bezel or chapter-ring concept
crown setting behaviour

NH37

A movement with date and 24-hour indication.

This requires separate display planning.

NH38

A no-date or open-heart related movement depending on exact execution.

This can alter dial-side layout and calendar assumptions.

NH39

A related movement with 24-hour indication and different display requirements.

Each movement variant requires its own technical review.

Shared family architecture does not prove complete case interchangeability.

Relationship to SW200-1 and Miyota 9015

The NH35 / NH36 occupies a different design position from the Sellita SW200-1 and Miyota 9015.

Compared with the Sellita SW200-1, the NH35 / NH36 is generally:

more affordable
less prestigious
lower frequency
larger in practical casing diameter
more strongly associated with modding and affordable microbrands

Compared with the Miyota 9015, the NH35 / NH36 is:

thicker
less suitable for slim automatic cases
lower frequency
more widely supported by modding parts
strongly associated with robust tool-watch architecture

These comparisons matter because movement choice affects the complete watch architecture.

Changing from an SW200-1 or Miyota 9015 to an NH35 / NH36 changes:

movement cavity requirements
spacer relationship
stem relationship
axial stack
caseback planning
dial interface
calendar display
rotor clearance
finished case-thickness potential

The NH35 / NH36 must therefore be treated as a movement family with its own engineering requirements, not merely as a cheap or common substitute for another calibre.

Related comparison reference: SW200-1 vs NH35 vs Miyota 9015

What NH35 / NH36 Does Not Decide

The movement does not define:

final case diameter
bezel design
lug geometry
case-wall thickness
crown shape
crown-tube installation
caseback profile
gasket selection
crystal system
rehaut depth
dial opening
finishing specification
machining strategy
external proportion

A common movement reduces one category of sourcing difficulty.

It does not replace case engineering.

The movement establishes the internal reference.

The designer must convert that reference into:

controlled geometry
tolerance behaviour
assembly logic
inspection criteria
prototype validation
repeatable production architecture

Common NH35 / NH36 Case-Design Mistakes

Treating 27.40 mm as the only important diameter

The 29.36 mm casing diameter with dial holding spacer is often the more practical case-design reference.

Ignoring the dial holding spacer

The spacer can control radial location, movement seating, dial support, assembly behaviour, and service removal.

Assuming modding compatibility equals engineering compatibility

A component fitting a popular mod case does not prove suitability for a new manufacturable case design.

Positioning the crown visually

The crown tube must be positioned from the movement stem axis.

Treating NH35 and NH36 calendar interfaces as identical

NH35 is date-only. NH36 is day-date. The dial interface changes.

Ignoring day-date aperture requirements on NH36

The day-date display must be coordinated with dial printing, movement rotation, and calendar correction.

Reducing caseback depth without checking rotor clearance

The automatic rotor requires a protected operating envelope.

Failing to validate hand-to-crystal clearance

The hand stack can fail even if the movement and spacer fit correctly.

Using the caseback to crush or trap the movement

Retention should be deliberate and repeatable.

Allowing the spacer or movement to shift radially

Spacer movement can disturb the crown axis, dial position, and calendar display.

Ignoring machining and finishing allowance

A correct nominal CAD model may become wrong after real manufacturing variation.

Adding gasket geometry after the case has been designed

Sealing affects wall thickness, axial stack, threads, crown alignment, and caseback architecture.

Assuming broad parts availability guarantees correct tolerances

Availability is not the same as engineering control.

Designing without an assembly sequence

A component can fit in CAD but remain impossible to install or service.

Treating one successful prototype as production proof

A working prototype demonstrates possibility.

Production requires repeatability.

CAD Difficulty Assessment

The NH35 / NH36 can appear simple in CAD because it is common, widely supported, and used in many modding projects.

That impression is misleading.

A basic visual representation is relatively straightforward.

A professional, manufacturable, serviceable, and tolerance-aware NH35 / NH36 case is considerably more demanding.

Task	Approximate difficulty
Basic conceptual movement placement	2/10
Functional modding-style compatibility	4/10
Professional movement-fit case architecture	7/10

The main difficulty lies in:

spacer relationship
radial tolerance
movement location
crown feel
stem alignment
rotor clearance
caseback depth
dial-side stack
calendar positioning
water-resistance geometry
repeatable assembly
service access

A beginner can place the NH35 inside a circular cavity.

A professional case design defines how the movement and spacer are located, protected, sealed, retained, and serviced through real manufacturing variation.

Physical-Sample Validation

Manufacturer documentation establishes the nominal technical basis.

Physical inspection confirms the actual components entering the project.

Before final CAD release, compare the documentation with:

physical NH35 or NH36 movement
dial holding spacer
selected dial
intended hand set
setting stem
crown
crown tube
movement holder
prototype components

Where practical, inspect:

outside movement diameter
casing diameter with spacer
total movement height
stem-axis relationship
setting-stem positions
rotor envelope
dial interface
date or day-date position
spacer geometry
hand-height execution
crown-tube relationship

Physical measurements should not casually override official drawings.

Measurement uncertainty, access limitations, and component condition must be considered.

Where the drawing, supplier information, and physical component appear to disagree:

stop the design release
identify the discrepancy
verify document revision
confirm movement execution
consult the supplier or manufacturer where necessary
record the resolution

An unresolved discrepancy should not be hidden inside an arbitrary clearance.

NH35 / NH36 Pre-Prototype Verification Checklist

Before releasing the case for prototyping, confirm that:

physical calibre is identified as NH35 or NH36
exact movement execution is recorded
technical-document revision is recorded
27.40 mm outside movement diameter is understood
29.36 mm casing diameter with dial holding spacer is understood
5.32 mm total height is understood as movement height only
NH35 date or NH36 day-date display is confirmed
hand-fitting-height execution is confirmed
dial specification is confirmed
dial attachment is confirmed
date or day-date aperture is coordinated
setting-stem option is confirmed
crown system is confirmed
dial holding spacer strategy is defined
locating datum is defined
radial locating interface is defined
holder or spacer system is defined
stem-release access is preserved
anti-rotation control is defined
spacer movement is prevented
radial tolerances are assigned
axial tolerances are assigned
rotor clearance is protected
caseback clearance is checked at worst case
stem axis is transferred into the case datum system
crown-tube alignment is verified
crown positions are verified
dial-seat height is controlled
calendar-window position is coordinated
hand-to-hand clearance is protected
hand-to-dial clearance is protected
hand-to-marker clearance is protected
hand-to-rehaut clearance is protected
hand-to-crystal clearance is protected
movement lift is controlled
movement rotation is controlled
gasket compression does not compromise movement clearance
machining allowances are included
finishing allowances are included
inspection methods exist
assembly order has been reviewed
service removal is possible
physical-sample inspection is recorded
representative production components will be used in the prototype

This checklist does not replace production drawings or prototype testing.

It controls the principal NH35 / NH36 movement-to-case risks before manufacture begins.

Movement-Led NH35 / NH36 Case-Design Workflow

Confirm the movement.

Identify whether the project uses NH35, NH36, or another NH3 Series movement.

Confirm the calendar requirement.

Decide whether the design requires date only, day-date, GMT, no-date, open-heart, or another NH3-family display.

Secure the official documentation.

Record the document title, revision, date, and source.

Create the project movement record.

Record the physical marking, supplier, dial, hands, stem, spacer, holder, crown system, caseback type, and calendar notes.

Extract manufacturer geometry.

Review the 27.40 mm outside movement diameter, 29.36 mm casing diameter with dial holding spacer, 5.32 mm total height, stem axis, calendar display, automatic-winding architecture, and casing references.

Inspect the physical components.

Compare the actual movement, spacer, and selected parts against the documented specification.

Select the locating architecture.

Define whether the spacer, holder, or another feature establishes position.

Resolve radial fit.

Allocate clearance and tolerance at the selected locating interface.

Resolve anti-rotation.

Provide rotational control independent of the setting stem.

Resolve the axial stack.

Build the complete stack from caseback to crystal.

Protect the rotor.

Resolve internal caseback geometry before fixing the exterior profile.

Transfer the stem axis.

Position the case-wall bore and crown tube from the movement datum system.

Resolve the crown system.

Establish stem length, crown diameter, winding access, tube projection, crown seating, and gasket behaviour.

Resolve dial, calendar, and hands.

Coordinate dial seat, date or day-date aperture, selected hand height, rehaut, and crystal.

Define retention.

Control radial movement, axial lift, spacer movement, and rotation without distorting the movement.

Preserve service access.

Ensure that stem release, spacer, holder, and removal sequence remain practical.

Integrate sealing.

Coordinate crown, crystal, and caseback sealing with the existing architecture.

Apply tolerances.

Assign tolerances and inspection methods to all critical interfaces.

Validate assembly and service.

Confirm that the watch can be assembled, wound, set, opened, and serviced without damage.

Build and inspect the prototype.

Use representative components and record deviations from CAD.

This sequence prevents the common mistake of assuming that widespread movement use and parts availability equal automatic case compatibility.

Related engineering reference: Movement to Case Fit

Prototype Validation

The first prototype is an engineering test article.

After assembly, verify that:

movement enters without forced seating
dial holding spacer remains undistorted
holder or spacer seats correctly
retention features seat correctly where used
stem-release access remains accessible
movement cannot shift radially
spacer cannot shift radially
movement cannot rotate
movement cannot lift axially
stem enters without lateral deflection
winding is smooth
time setting is smooth
date correction operates correctly on NH35
day-date correction operates correctly on NH36
crown positions are distinct
dial remains centred
date aperture remains aligned
day-date aperture remains aligned where applicable
hands clear one another
hands clear the dial
hands clear applied markers
hands clear the rehaut
hands clear the crystal
rotor rotates freely
no caseback witness marks appear
no abnormal rotor noise is present
caseback sealing does not reduce rotor clearance
crown and crystal sealing function as intended
case can be reopened
movement can be removed
movement can be recased repeatably

Where appropriate, repeat checks:

dial up
dial down
crown up
crown down
before final caseback tightening
after final assembly
after repeated winding
after normal motion tests
after sealing tests
after reopening and recasing

Prototype Measurement Record

For each prototype, record:

prototype revision
CAD revision
technical-document revision
movement identification
NH35 or NH36 selection
dial holding spacer identification
dial identification
calendar display type
hand-set identification
hand-height execution
date or day-date alignment
crown and tube identification
stem option
holder or spacer revision
radial-interface measurement
movement seating position
caseback clearance
dial position
hand clearances where practical
winding observations
setting observations
calendar-correction observations
sealing-test result
failed checks
corrective action
final disposition

Possible dispositions include:

accepted
accepted with controlled deviation
rework required
redesign required
rejected

A prototype should not be accepted merely because it can be assembled.

Acceptance requires correct location, free operation, calendar alignment, serviceability, structural adequacy, and conformity with the intended engineering requirements.

Production Acceptance Criteria

Before approving the architecture for production, confirm that:

critical dimensions have tolerances
tolerances reflect the manufacturing process
inspection methods exist
worst-case conditions have been reviewed
movement installation is repeatable
spacer installation is repeatable
movement retention is repeatable
anti-rotation is repeatable
crown function is repeatable
rotor clearance is repeatable
dial and calendar alignment are repeatable
hand clearance is repeatable
sealing is repeatable
disassembly and recasing are repeatable
approved deviations are documented
production samples match the approved prototype

One successful prototype proves possibility.

Production approval requires repeatability.

Related HorologyCAD Engineering Pages

Continue through the movement-led case-design system.

Start With Movement Fit

Movement Selection
Movement to Case Fit
Internal Case Geometry & Movement Cavity Sizing

Define Clearance and Case Architecture

Resolve Crown, Stem, Dial, and Hands

Control Retention, Sealing, and Manufacturing

Movement Securing Methods
Water Resistance Engineering in Watch Cases
Caseback Sealing System
Watch Case Tolerances
CNC Machining Constraints in Watch Cases

Continue the NH35 / NH36 Cluster

Compare With Related Movements

Miyota 9015 Dimensions & Technical Data
Miyota 8215 Dimensions & Technical Data
Sellita SW200-1 Dimensions & Technical Data
Sellita SW300-1 Dimensions & Technical Data
ETA 2824-2 Dimensions & Technical Data
ETA 2892-A2 Dimensions & Technical Data

HorologyCAD Design Position

The NH35 / NH36 is not merely a common automatic movement specification.

It is a fixed internal engineering system around which the watch case must be developed.

Its 27.40 mm outside movement diameter, 29.36 mm casing diameter with dial holding spacer, 5.32 mm total height, stem axis, calendar interface, hand-fitting execution, automatic rotor, spacer relationship, and retention requirements all influence the finished watch.

When those relationships are interpreted correctly, the designer can create a case that:

assembles predictably
locates the movement and spacer accurately
controls rotation
protects the automatic system
aligns the crown and stem
preserves date or day-date alignment
preserves dial and hand clearance
supports water resistance
controls manufacturing variation
can be inspected
remains serviceable

The principle is straightforward:

Begin with verified manufacturer data, establish the internal case architecture, control the spacer relationship, validate using real components, and develop the exterior around a mechanically resolved system.

Compatibility must be engineered.

It cannot be assumed.

Next Step

For the complete movement-to-case relationship:

→ Movement to Case Fit

For movement-cavity sizing and location logic:

→ Internal Case Geometry & Movement Cavity Sizing

For NH35 / NH36-specific failure boundaries:

→ NH35 / NH36 Case Design Constraints

For the applied NH35 / NH36 design process:

→ NH35 / NH36 Case Design Guide

Return to HorologyCAD

HorologyCAD is a movement-led watch case design system for developing case architecture around real mechanical movements, manufacturable constraints, and functional assembly requirements.

→ Movement-Led Watch Case Design & Engineering

Technical Note

This page is based on identified NH3 Series technical documentation and current NH35 / NH36 reference checks.

Last checked against identified manufacturer documentation: 22 June 2026.

Manufacturer data should always be checked against the current NH3 Series technical documentation, the exact movement execution, the selected dial and calendar configuration, the dial holding spacer, and the physical movement used in the project.

HorologyCAD engineering guidance on case geometry, clearance, spacer fit, retention, stem alignment, rotor clearance, sealing, assembly, robust automatic architecture, calendar alignment, and validation is interpretive design guidance. Final case architecture should be confirmed against physical components, prototype assembly, and production inspection.