The Sellita SW200-1 is an 11½-ligne Swiss automatic mechanical movement widely used in independent, microbrand, and established production watches.

For watch case design, the SW200-1 should not be treated as a simple circular object with a diameter and height. It is a fixed internal mechanical system with casing geometry, stem-axis requirements, dial-side relationships, rotor clearance requirements, hand-height options, clamp arrangements, and service-access needs.

The headline dimensions identify the movement.

They do not define the finished watch case.

A professional SW200-1 case must resolve four linked engineering groups:

movement location and retention
radial clearance, axial stack, and rotor protection
stem-axis, crown-tube, dial, date, and hand-height relationships
sealing, tolerances, assembly, inspection, and service access

HorologyCAD treats the SW200-1 as a benchmark movement for movement-led watch case design because it demonstrates the difference between reading a manufacturer specification and converting that information into a manufacturable, serviceable, and tolerance-aware case architecture.

This page separates two information layers:

Official Sellita Manufacturer Data

Specifications, dimensions, drawings, and movement relationships defined by Sellita documentation.

HorologyCAD Engineering Interpretation

Case-design guidance explaining how those manufacturer references affect movement location, clearance, retention, assembly, sealing, serviceability, and manufacturability.

Manufacturer documentation defines the movement.

HorologyCAD explains what that movement requires from the case.

Specification	Manufacturer reference
Calibre	Sellita SW200-1
Movement type	Swiss automatic mechanical
Ligne size	11½ lignes
Overall movement diameter	26.00 mm
Case-fitting diameter	25.60 mm
Movement height	4.60 mm
Frequency	28,800 A/h / 4 Hz
Jewels	26
Running time	Minimum 38 hours; typical 41 hours
Winding	Automatic and manual
Stop seconds	Yes
Display	Central hours, minutes, and seconds; date window with quick correction in the documented execution
Oscillating weight	Heavy-metal segment with ball-bearing support
Balance lift angle	50°
Total setting-stem travel	0.80 mm
Standard hand-fitting execution	Height 2
Case-design status	Execution dependent

SW200-1 Quick Reference

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.

SW200-1 Quick Reference Card

Key Design Note

The 26.00 mm overall movement diameter and 25.60 mm case-fitting diameter describe different physical relationships.

The 26.00 mm dimension identifies the broader physical movement envelope.

The 25.60 mm dimension identifies the principal manufacturer-defined casing-fit reference.

Neither dimension automatically defines the finished case cavity.

The 4.60 mm movement height also does not define the total finished watch thickness.

Final case geometry must additionally account for:

locating surfaces
holder or casing-ring geometry
assembly clearance
anti-rotation control
casing clamps
dial support
selected hand height
rotor clearance
caseback construction
crown and stem alignment
gasket systems
manufacturing variation
service access

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

Official Manufacturer Source

Item	Reference
Manufacturer	Sellita Watch Co. SA
Calibre	SW200-1
Primary document	Sellita SW200-1 Technical Documentation
Document revision	07
Document date	2 September 2024
HorologyCAD archive reference	HC-MTS-SW200-1-REV07

The official Sellita technical document is the primary source for manufacturer-defined information on this page.

It contains information relating to:

movement specifications
movement grades and timing criteria
winding and testing
component identification
movement assembly
automatic winding assembly
setting-stem removal
theoretical inner movement position
casing frame
casing fits
casing-clamp options
dial indications
date geometry
hand-fitting heights
hand-fitting heights without central seconds
setting-stem length
crown position
screw-down crown relationships

Where information is described as official manufacturer data, it should be traceable to the relevant Sellita document section.

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

Manufacturer-Document Use

The original Sellita technical documentation should be linked for attribution and verification.

The manufacturer drawings contain protected technical material. HorologyCAD should therefore not reproduce complete Sellita drawings without the appropriate permission.

HorologyCAD technical visuals and explanations should be:

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

This maintains a clear distinction between:

Sellita documentation
HorologyCAD engineering interpretation
HorologyCAD original explanatory material

Readers should consult the original manufacturer document for the complete Sellita specification.

Verification and Revision Notes

Item	Status
Manufacturer	Sellita Watch Co. SA
Calibre	SW200-1
Primary source	Sellita SW200-1 Technical Documentation
Document revision	07
Document date	2 September 2024
Initial HorologyCAD source review	17 June 2026
Manufacturer documentation audit	Completed
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 the identified Sellita technical documentation.

The audit covers:

headline specifications
overall and case-fitting diameters
movement height
casing-frame geometry
casing options
casing clamps
dial interface
date-window geometry
hand-fitting-height system
stem length
setting-stem travel
crown position
crown-impact guidance
screw-down crown operating positions
movement grades
timing criteria
winding-test information
setting-stem removal

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

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

Configuration Warning

Final case geometry must be checked against:

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

Nominal similarity to the ETA 2824-2 or another Sellita-family movement does not prove complete casing interchangeability.

SW200-1 Compared With Other Common Watch Movements

The SW200-1 is one of several common automatic movements used in modern watch case design. Comparing it with alternatives such as the ETA 2824-2, Sellita SW300-1, Miyota 9015, and Seiko NH35 helps show why movement diameter, height, stem position, rotor clearance, and caseback architecture must be considered before the external case shape is finalised.

Technical Source Classification

The following hierarchy applies throughout this page.

Level A — Direct Manufacturer Specification

A value stated explicitly in official Sellita documentation.

Level B — Manufacturer Drawing Interpretation

A dimension or relationship read directly from an official Sellita technical drawing.

Level C — Execution-Dependent Manufacturer Information

A value or relationship that may change according to movement execution, date arrangement, dial configuration, hand-fitting height, supplied stem, or casing components.

Level D — HorologyCAD Engineering Interpretation

Case-design guidance developed from manufacturer information and movement-led engineering principles.

Level E — Project-Specific Validation

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 Sellita specifications.

Manufacturer Source Register

Subject	Sellita document page
Technical specifications	Page 3
Winding, running time, and movement grades	Page 4
Timing and performance criteria	Page 5
Component list	Pages 6–7
Movement assembly	Pages 8–17
Setting-stem removal	Page 18
Frame for case	Page 19
Casing options and clamps	Page 20
Dial indications	Pages 21–22
Hand-fitting heights	Page 23
Hand-fitting heights without central seconds	Page 24
Setting-stem length and crown position	Page 25
Screw-down crown positions	Page 26

The visible Sellita document page numbers should be used when referring readers to the manufacturer PDF.

Manufacturer Data Register

Data item	Manufacturer reference	Source class
Calibre	SW200-1	Level A
Overall movement diameter	26.00 mm	Level A / B
Case-fitting diameter	25.60 mm	Level A / B
Movement height	4.60 mm	Level A
Frequency	28,800 A/h / 4 Hz	Level A
Jewel count	26	Level A
Running time	Minimum 38 hours; typical 41 hours	Level A
Balance lift angle	50°	Level A
Total setting-stem travel	0.80 mm	Level B
Casing fits	Multiple manufacturer-defined options	Level B / C
Casing clamps	Multiple options	Level B / C
Dial geometry	Execution dependent	Level B / C
Revised date-window dimension	2.30 mm	Level B / C
Revised date-window centre distance	10.40 mm	Level B / C
Hand-fitting heights	Eight three-hand arrangements	Level B / C
Standard hand-fitting execution	Height 2	Level B / C
Hand heights without central seconds	Separate manufacturer table	Level B / C
Normal setting-stem option	Manufacturer-defined	Level B / C
Long setting-stem option	Manufacturer-defined	Level B / C
Setting-stem thread	S0.90	Level B
Crown-to-middle maximum gap	0.10 mm	Level A / B
Movement grades	Elaboré, Top, and Chronomètre	Level A
Stem-removal tool	1.00 mm screwdriver	Level A
Stem-removal position	Time-setting position	Level A

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

applicable drawing page
document revision
exact movement execution
drawing convention
stated tolerance

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
calibre
physical movement marking
movement grade
supplier
purchase date
date execution
hand-fitting-height code
dial specification
dial thickness
dial attachment
intended hand set
setting-stem option and reference
selected casing clamp
clamp bend and length
clamp screw type
movement-holder strategy
crown type
crown-tube architecture
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 “SW200 case.”

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

Why the SW200-1 Matters

The SW200-1 occupies an important position in practical Swiss automatic watchmaking.

Its value does not come from rarity.

It comes from being:

established in production
familiar to watchmakers
serviceable
commercially realistic
suitable for independent brands
supported by an established supplier and service ecosystem
recognised by collectors

These qualities reduce movement-selection risk.

They do not remove case-design risk.

A familiar movement can still be integrated badly.

Poor SW200-1 integration can produce:

rough winding
poor setting feel
crown and stem misalignment
rotor contact
weak movement retention
date-window misalignment
dial displacement
insufficient hand clearance
excessive watch thickness
sealing problems
difficult servicing

A correctly integrated SW200-1 can produce a watch that feels robust, controlled, and professionally resolved.

The difference lies in the surrounding architecture.

Sellita and the SW200 Family

The SW200 family belongs to the established 11½-ligne Swiss automatic movement category used across practical three-hand watches.

Sellita is a Swiss movement manufacturer based in La Chaux-de-Fonds, an important centre of Swiss watchmaking. The company became especially important to the wider watch industry as independent and non-integrated brands sought reliable Swiss mechanical movements outside fully in-house production. Within that context, the SW200 family became one of the most widely used practical Swiss automatic movement families for brands requiring a familiar, serviceable and well-documented calibre.

The SW200-1 became particularly relevant to independent and non-integrated brands requiring a recognised and serviceable Swiss automatic movement without developing a proprietary calibre.

Current Calibre Status

This page covers the Sellita SW200-1.

Sellita has since introduced the SW200-2 as an evolution of the SW200 family.

An SW200-1 project must be validated against SW200-1 documentation.

An SW200-2 project must be validated separately against the technical information applicable to the SW200-2.

The SW200-1 remains important because it continues to appear in:

existing production watches
service and repair work
legacy designs
replacement-case projects
established dial and hand programmes
independent-brand products
microbrand watches

The purpose of this page is not to present the SW200-1 as Sellita’s latest movement development.

It is to provide a rigorous engineering reference for projects that actually use the SW200-1.

Movement Architecture

The documented SW200-1 execution provides:

central hours
central minutes
central seconds
date through a window
quick date correction
automatic winding
manual winding
stop seconds
central oscillating weight with a heavy-metal segment
ball-bearing rotor support
conventional dial-side hand and calendar architecture

The architecture is familiar.

It is not mechanically trivial.

The case designer must coordinate:

overall movement envelope
casing-fit diameter
stepped movement geometry
locating surfaces
holder or casing ring
casing clamps
dial attachment
date display
selected hand stack
setting stem
keyless works
crown tube
crown
rotor envelope
caseback
rehaut
crystal
gaskets

The SW200-1 is not an ultra-thin movement.

Its movement height and automatic winding system must be considered before the external case profile is fixed.

SW200-1 Movement Architecture Diagram

Movement Grades and Timing Performance

Sellita identifies several SW200-1 movement grades, including:

Elaboré
Top
Chronomètre

Movement grade should not be confused with movement variant.

A grade principally concerns:

regulation
positional performance
quality-control limits
component selection
finishing
commercial positioning

A movement variant or execution may affect physical case integration through:

calendar arrangement
hand-fitting height
display system
dial geometry
supplied casing components

Manufacturer timing criteria are useful for:

movement specification
procurement
quality control
regulation expectations
final product positioning

They do not change the basic 26.00 mm overall envelope, 25.60 mm case-fitting diameter, or 4.60 mm movement height.

The exact grade should nevertheless be recorded in the project movement register.

Appropriate Applications and Limitations

The SW200-1 offers a practical balance of:

Swiss manufacture
serviceability
supplier availability
production familiarity
collector recognition
established technical documentation
suitability for modest production volumes

It is particularly appropriate for:

dive watches
field watches
pilot watches
tool watches
sports watches
robust dress watches
independent-brand production
serviceable long-term watches

It is less naturally suited to projects centred on:

extreme thinness
unusually long power reserve
unconventional display architecture
movement decoration as the main visual attraction

These are application boundaries rather than defects.

The movement should be selected because it suits the intended watch architecture.

Movement origin cannot compensate for weak case integration.

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
holder geometry
casing-clamp use
radial clearance
anti-rotation
axial retention
stem-axis transfer
crown-tube geometry
rotor protection
caseback depth
dial support
hand 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.

SW200-1 Casing Envelope

Sellita’s casing-frame drawing defines the SW200-1 as a stepped three-dimensional movement envelope.

It distinguishes between:

26.00 mm overall movement diameter
25.60 mm principal case-fitting diameter
smaller stepped movement-body regions
dial-side and caseback-side axial references
movement support relationship
setting-stem centreline
total setting-stem travel

These dimensions serve different functions.

The 26.00 mm dimension describes the broader physical movement envelope.

The 25.60 mm dimension identifies the principal manufacturer casing-fit reference.

The smaller stepped diameters describe additional body and support geometry that may affect:

movement-holder design
internal cavity relief
clamp access
movement insertion
service removal
component clearance

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

The designer must determine:

which feature locates the movement
which regions require clearance
which surface establishes the support plane
how the holder or clamps interact with the case
how the complete movement enters and leaves the case

Sellita also instructs that the distance to the movement centre should be checked before casing a production series.

This supports an important HorologyCAD principle:

Nominal source geometry establishes the design basis, but production release still requires project-specific verification.

Related engineering reference: Internal Case Geometry & Movement Cavity Sizing

SW200-1 Internal Case Envelope Diagram

Movement Diameter and Internal Case Geometry

The 25.60 mm case-fitting dimension establishes a manufacturer casing reference.

It does not automatically establish the finished case-cavity diameter.

The internal case may also need to accommodate:

a movement holder
casing ring
locating shoulders
casing clamps
clamp screws
radial assembly clearance
coating or finishing buildup
anti-rotation features
inspection access
service-tool access

A cavity modelled directly at the nominal movement dimension may become difficult or impossible to assemble after manufacturing variation is introduced.

It may also apply uncontrolled force to the movement or holder.

The designer must define:

which component contacts the case
which surface establishes concentricity
which feature limits radial movement
which feature prevents rotation
how the movement enters the case
how the movement is removed for service

The objective is not merely to make the movement fit.

The objective is to locate it predictably.

Related engineering reference: Internal Case Geometry & Movement Cavity Sizing

Official Casing-Clamp Options

Sellita provides multiple manufacturer-defined casing-clamp arrangements for the SW200-1.

The manufacturer documentation identifies variations including:

short clamps
long clamps
differing bend forms
standard fixing screws
alternative screw-head arrangements
defined clamp positions relative to the movement and stem
a dedicated area for setting-stem removal

The selected clamp may change:

internal ledge height
radial space
screw depth
screwdriver access
axial retention
assembly order
service access

The exact clamp and screw reference should be recorded before the internal case geometry is finalised.

A generic “SW200 clamp” does not describe every manufacturer-supported arrangement.

Casing clamps retain the movement.

They should not be used to compensate for:

excessive radial clearance
poor concentricity
incorrect holder geometry
misaligned stem geometry
inadequate anti-rotation control

Movement location and movement retention are related but distinct functions.

Radial Clearance and Movement Location

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

The relevant interface may be:

movement to case
movement to holder
holder to case
casing ring to case
clamp system to case

The correct allowance depends on:

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
movement or holder distortion
stem-axis displacement
surface damage
dependence on hand fitting

Excessive clearance can produce:

radial movement
rotation
date-window displacement
dial movement
stem side loading
inconsistent crown feel
overdependence on clamps

There is no responsible universal cavity addition suitable for every SW200-1 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 holder rotation.

Rotation can affect:

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

Anti-rotation may be provided through:

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 SW200-1 movement height is 4.60 mm.

That dimension represents only one part of the complete watch stack.

Finished thickness must also account for:

movement seating
dial support
dial thickness
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 movement height alone will usually be incorrect.

Potential consequences include:

rotor contact
hand contact
movement compression
excessive caseback depth
greater finished thickness than expected
incorrect crown-axis position

A well-proportioned SW200-1 case is possible.

The complete axial stack must be resolved before the exterior thickness is fixed.

Related engineering reference: Movement Height vs Case Thickness

Axial Stack Control

The axial stack controls the vertical relationship between:

caseback
rotor
movement
movement seat
dial
hands
rehaut
crystal

The movement must be protected on both sides.

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 and hands.

Insufficient axial space can cause:

rotor rubbing
hand contact
dial loading
movement compression
caseback interference

Excessive uncontrolled space can cause:

movement lift
dial movement
stem misalignment
retention inconsistency
impact noise

Axial clearance is not arbitrary empty space.

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

Related engineering reference: Axial Clearance

SW200-1 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
rotor motion
rotor endshake
manufacturing tolerance
caseback deflection
gasket compression
finishing buildup
shock loading

Insufficient clearance can cause:

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

A common mistake is to reduce caseback depth in pursuit of a thinner-looking watch without protecting the rotor envelope.

The rotor space should be resolved before the external caseback profile is finalised.

The caseback must then 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 Test Information

The SW200-1 supports automatic and manual winding.

Sellita also provides controlled winding and test instructions for workshop and production use.

These instructions relate to:

manual winding through the stem
powered winding equipment
testing with the automatic winding system installed
testing without the automatic system installed

These are servicing and controlled-test procedures rather than everyday user instructions.

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

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

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 correction
keyless-works loading
crown-gasket alignment
crown-guard geometry

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
premature wear
visibly incorrect crown position

The movement support plane, 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

Setting-Stem Length and Crown Position

Sellita provides normal and long setting-stem options.

Setting-stem option	L	L1	L2
Normal	15.50 mm	8.45 mm	21.25 mm
Long	20.00 mm	12.95 mm	25.75 mm

The setting-stem thread is identified as S0.90.

These are manufacturer component references.

They do not directly define the final cut length for every case.

Final stem length must be derived from the assembled relationship between:

movement seating position
case wall
crown tube
crown internal geometry
winding and setting positions
gasket arrangement
screw-down travel where applicable

Sellita states that the gap between the crown and the middle case must not exceed 0.10 mm when the movement is fixed in the case.

The purpose is functional.

An excessive gap can increase the risk that an impact on the crown transfers damaging load through the setting stem into the movement.

The crown-to-middle relationship should therefore be treated as:

an impact-protection requirement
a stem-loading consideration
an operating-position constraint
a sealing-system relationship

It is not merely an exterior styling gap.

The final stem should never be shortened by visual judgement alone.

Its length should be established using the actual movement, case, tube, and crown assembly.

Related engineering reference: Stem Height to Crown Tube Position Relationship

Screw-Down Crown Operating Positions

Sellita provides a dedicated screw-down crown-position drawing for the documented SW200-1 arrangement.

The total 0.80 mm setting-stem travel is divided into two manufacturer-defined operating segments.

The drawing also includes force references for the illustrated crown mechanism.

These values describe the manufacturer’s documented operating relationship.

They do not prescribe one universal crown, tube, spring, or gasket design for every SW200-1 case.

A project-specific screw-down crown system must still be validated for:

thread engagement
crown release
winding position
date-correction position
time-setting position
spring preload
gasket compression
stem alignment
operating force

Dial Interface and Date-Window Geometry

Sellita provides dedicated dial-interface drawings for the SW200-1.

These define manufacturer relationships for:

dial retention
dial support
centre-hole geometry
dial-side clearance
date-disc position
date-window size
date-window centre distance
attachment locations

For the documented date-equipped execution, the revised drawing identifies:

Feature	Manufacturer reference
Dial centre hole	2.00 mm with stated positive tolerance
Dial attachment radius	11.60 mm
Attachment offset	3.78 mm
Dial-to-date-disc relationship	0.16 mm
Revised date-window dimension	2.30 mm
Revised date-window centre distance	10.40 mm

These values apply to the documented dial execution.

They should not be assumed to describe every supplier dial, modified calendar arrangement, or custom no-date configuration.

The final dial and case system must coordinate:

movement concentricity
rotational orientation
dial retention
dial thickness
centre-hole clearance
date-window position
rehaut opening
chapter-ring geometry
applied-marker clearance
hand-stack clearance

Small movement-location errors can become visually obvious at the date aperture.

A movement may remain mechanically operational while the date appears displaced because of:

radial movement
rotational movement
incorrect dial location
incorrect aperture position
cumulative tolerance error

The case should not be used to compensate for an incorrectly designed dial.

Movement, dial, date display, and case opening should be developed as one controlled assembly.

Related engineering reference: Dial Integration & Case Interface

Dial Attachment

The Sellita drawing identifies a manufacturer-defined dial-locking arrangement.

The final dial programme must confirm:

attachment method
locking geometry
engagement
dial thickness
date-disc clearance
service release method

The case should not compensate for an incorrectly specified dial.

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

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

Hand-Fitting Heights and Crystal Clearance

Sellita provides eight three-hand fitting-height arrangements for the SW200-1.

Hand-fitting height 2 is identified as the standard arrangement.

Additional heights are available as special configurations.

Sellita also provides a separate table for arrangements without a central seconds hand.

This matters because the selected hand-height execution changes:

cannon-pinion length
hour-wheel height
seconds-pinion height
hand-seat position
dial-to-hand relationship
hand-to-hand spacing
required rehaut depth
crystal clearance
total dial-side stack

The case designer must record the exact hand-fitting-height code before fixing:

dial thickness
applied-marker height
rehaut geometry
hand profile
crystal underside position

“SW200-1 hand height” is not one universal dimension.

It is a selected manufacturer execution.

The complete system must protect against contact between:

hour hand and dial
minute hand and hour hand
seconds hand and minute hand
hands and applied markers
hands and rehaut
upper hand and crystal

Movement fit, rotor clearance, and crown alignment can all be correct while the watch still fails because of hand contact.

Detailed Hand-Height Data

The complete manufacturer hand-height tables should be made available through:

an expandable technical-reference section
a separate HorologyCAD reference table
or direct consultation of the official Sellita document

The main article should identify the standard Height 2 execution without overwhelming the introductory specification layer.

Movement Holder and Retention Strategy

The SW200-1 must be retained securely without being:

distorted
pinched
allowed to shift
allowed to rotate

A complete retention system should control:

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

Possible strategies include:

manufacturer-style casing clamps
dedicated movement holder
casing ring
spacer ring
locating shoulders
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

Sellita defines a specific procedure for removing the SW200-1 setting stem.

The movement should first be placed in the time-setting position.

The setting-lever axis is then pressed using a 1.00 mm screwdriver before the stem is withdrawn.

Sellita warns against using pointed tools such as tweezers because excessive or poorly controlled pressure may jam the setting lever or damage the setting-lever spring.

This procedure creates a direct case-design requirement.

The case architecture should provide:

visible access to the release point
sufficient screwdriver approach
adequate clearance around the movement
stable support during stem removal
a service sequence that avoids levering against finished surfaces

The release point should not be hidden behind:

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 stem 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 misplaced 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

Water resistance is not added after movement fit is complete.

It is part of the same engineering 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 retains it
what prevents rotation
what controls the stem axis
what protects the rotor
what supports the dial
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.

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

Assembly and Service Access

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

The assembly sequence should define:

how the movement and dial assembly enter the case
how the setting stem is inserted
how the setting stem is removed
how the holder or clamps are installed
how rotation is controlled
how axial retention is applied
how rotor clearance is checked
how crown functions are tested
how sealing components are installed
how the watch is reopened for service

A design requiring excessive force, component distortion, inaccessible screws, or destructive disassembly is not fully resolved.

Serviceability is an engineering requirement.

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 SW200-1 movement
selected dial
intended hand set
setting stem
crown
crown tube
casing clamps
movement holder
prototype components

Where practical, inspect:

overall movement envelope
case-fitting region
movement height
stem-axis relationship
setting-stem travel
rotor envelope
dial interface
clamp geometry
hand-height execution

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.

Common SW200-1 Case-Design Mistakes

Treating the movement as a single 25.60 mm cylinder

The movement has a broader 26.00 mm envelope and additional stepped geometry.

Machining the cavity at exactly 25.60 mm

This ignores the actual locating interface, assembly method, tolerances, and finishing allowance.

Treating 4.60 mm as the finished watch thickness

Movement height excludes the dial, hands, crystal, rotor clearance, caseback, and sealing architecture.

Selecting the crown position visually

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

Guessing setting-stem length

Stem length must be derived from the actual case, tube, and crown system.

Ignoring the crown-to-middle limit

The manufacturer’s maximum-gap instruction is an impact-protection requirement, not only a visual consideration.

Ignoring hand-fitting height

Different hand-height executions alter the required dial-to-crystal stack.

Reducing caseback depth without checking the rotor

A thin external profile can create rotor interference.

Using the stem as an anti-rotation feature

The setting stem should not carry structural locating loads.

Relying on caseback compression to retain the movement

Retention should be deliberate and repeatable.

Ignoring date-window alignment

Small radial or rotational errors can create obvious visual displacement.

Assuming ETA 2824-2 interchangeability

Nominal similarity does not prove compatibility across every casing interface.

Adding sealing geometry after the case is designed

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

Blocking setting-stem release access

A secure casing system is still poor if the stem cannot be removed safely.

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.

Service Ecosystem and Long-Term Use

The SW200-1 benefits from broad watchmaker familiarity and an established servicing context.

It is suitable for watches intended to be:

maintained
regulated
repaired
recased
retained long term

Serviceability also imposes case-design requirements.

A well-resolved case should permit:

controlled stem removal
access to retention features
holder or clamp removal
non-destructive movement extraction
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 SW200-1 as a familiar and serviceable Swiss automatic movement rather than a rare or exotic calibre.

That perception depends heavily on the finished watch.

In a poorly resolved watch, the movement may feel generic.

In a well-engineered watch, it can feel:

dependable
maintainable
appropriately specified
professionally integrated
suitable for the product

Movement prestige cannot compensate for:

poor crown action
rotor contact
excessive thickness
weak retention
poor sealing
poor dial alignment
inconsistent assembly

The quality of integration determines whether the movement feels ordinary or correctly applied.

SW200-1 Ecosystem and Related Movements

The SW200-1 is often compared with the ETA 2824-2 because both occupy the same broad 11½-ligne Swiss automatic category.

That comparison is useful for:

movement selection
general dimensional context
service familiarity
product planning

It does not establish universal interchangeability.

The final case must still be checked against:

exact calibre
execution
current technical drawing
overall envelope
casing frame
dial interface
date configuration
hand-fitting height
setting stem
holder and clamp arrangement

The SW200-1 should also be understood within a broader movement ecosystem that may include:

ETA 2824-2 — a historically important reference point for this category
Sellita SW200-1 — the calibre covered by this page
Sellita SW300-1 — a thinner Sellita movement family requiring separate case architecture
Sellita SW400-1 — a larger related Sellita movement family requiring separate dimensional validation

Similar naming, similar function, or similar nominal diameter does not prove casing compatibility.

The word “compatible” should never replace dimensional verification.

What the SW200-1 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 proven movement reduces one category of uncertainty.

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

SW200-1 Pre-Prototype Verification Checklist

Before releasing the case for prototyping, confirm that:

physical calibre is identified as SW200-1
exact execution is recorded
technical-document revision is recorded
overall 26.00 mm envelope is understood
applicable 25.60 mm casing fit is identified
stepped movement geometry is accommodated
date arrangement is confirmed
hand-fitting-height execution is confirmed
dial specification is confirmed
dial attachment is confirmed
date aperture is coordinated
setting-stem option is confirmed
crown system is confirmed
crown-to-middle maximum is reviewed
locating datum is defined
radial locating interface is defined
holder or casing-ring system is defined
clamp type and screw are defined
stem-release access is preserved
anti-rotation control is defined
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
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 movement-to-case risks before manufacture begins.

Movement-Led SW200-1 Case-Design Workflow

1. Confirm the movement

Identify the exact calibre, execution, date arrangement, grade, hand height, and supplied components.

2. Secure the official documentation

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

3. Create the project movement record

Record the physical marking, supplier, dial, hands, stem, holder, clamps, and crown system.

4. Extract manufacturer geometry

Review the 26.00 mm envelope, 25.60 mm case-fitting reference, stepped casing geometry, dial interface, hand heights, stem information, and crown guidance.

5. Inspect the physical components

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

6. Select the locating architecture

Define which component establishes position.

7. Resolve radial fit

Allocate clearance and tolerance at the selected locating interface.

8. Resolve anti-rotation

Provide rotational control independent of the setting stem.

9. Resolve the axial stack

Build the complete stack from caseback to crystal.

10. Protect the rotor

Resolve internal caseback geometry before fixing the exterior profile.

11. Transfer the stem axis

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

12. Resolve the crown system

Establish stem length, operating positions, tube projection, crown-to-middle gap, and gasket behaviour.

13. Resolve dial and hands

Coordinate dial seat, revised date aperture, selected hand height, rehaut, and crystal.

14. Define retention

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

15. Preserve stem-removal access

Ensure the setting-lever release remains safely accessible.

16. Integrate sealing

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

17. Apply tolerances

Assign tolerances and inspection methods to all critical interfaces.

18. Validate assembly and service

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

19. Build and inspect the prototype

Use representative components and record deviations from CAD.

This sequence prevents the common mistake of designing the exterior first and forcing the movement into the remaining space.

Prototype Validation

The first prototype is an engineering test article.

After assembly, verify that:

movement enters without forced seating
holder or casing ring remains undistorted
casing clamps seat correctly
clamp screws remain accessible
setting-stem release remains accessible
movement 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
crown positions are distinct
crown-to-middle relationship is controlled
dial remains centred
date aperture remains aligned
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 sealing tests
after reopening and recasing

Prototype Measurement Record

For each prototype, record:

prototype revision
CAD revision
technical-document revision
movement identification
movement grade
dial identification
hand-set identification
hand-height execution
crown and tube identification
stem option
holder or clamp revision
radial-interface measurement
movement seating position
caseback clearance
dial position
date-window alignment
hand clearances where practical
winding observations
setting 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, serviceability, 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
movement retention is repeatable
stem access is repeatable
crown function is repeatable
rotor clearance is repeatable
dial and date 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 SW200-1 Cluster

SW200-1 Case Design Constraints
SW200-1 Case Design Guide
SW200-1 Case Core: Movement-Fit CAD System
SW200-1 vs NH35 vs Miyota 9015

HorologyCAD Design Position

The Sellita SW200-1 is not merely a list of specifications.

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

Its overall envelope, case-fitting diameter, movement height, stem axis, dial interface, hand-fitting execution, rotor, 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 accurately
controls rotation
protects the automatic system
aligns the crown and stem
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, validate it using real components, and develop the exterior around a mechanically resolved system.

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 SW200-1-specific failure boundaries:

→ SW200-1 Case Design Constraints

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 Sellita SW200-1 technical documentation, Revision 07, dated 2 September 2024.

Last checked against the identified manufacturer documentation: 21 June 2026.

Manufacturer data should always be checked against the current official Sellita documentation and the exact movement execution used in the project.

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