Definition
Movement selection defines the mechanical foundation from which the entire watch case is engineered.
The movement establishes:
external diameter
total height
stem position
dial interface geometry
All case geometry, clearances, and interfaces are derived from these parameters.
Movement selection is the first step in the HorologyCAD system.
Movement as a Fixed Constraint
A watch case is not designed independently.
It is built around a fixed movement.
Once selected, the movement defines:
case diameter range
case thickness limits
crown and stem alignment position
internal geometry envelope
Changing the movement after design begins invalidates the system.
Movement must be selected before any case geometry is defined.
Why Movement Selection Matters
Failure to define the movement results in:
incompatible case proportions
misaligned crown and stem geometry
insufficient internal clearance
assembly failure
A valid case design begins with a known movement and proceeds outward from that constraint.
Core Movement Options
The following movements define the primary design architectures within HorologyCAD.
Each represents a distinct constraint set.
Sellita SW200-1
Diameter: ~25.6 mm
Height: ~4.6 mm
Standard automatic architecture with balanced proportions.
→ Use for: general-purpose automatic case design
→ Continue: Movement to Case Fit
Seiko NH35
Diameter: ~27.4 mm
Height: ~5.3 mm
Larger diameter and increased thickness.
→ Use for: robust, thicker case designs
→ Continue: Movement to Case Fit
Miyota 9015
Diameter: ~26.0 mm
Height: ~3.9 mm
Reduced height automatic movement for slimmer cases.
→ Use for: thin automatic case architecture
→ Continue: Movement to Case Fit
ETA 2892-A2
Diameter: ~25.6 mm
Height: ~3.6 mm
Thin, higher-grade movement architecture.
→ Use for: reduced thickness and refined designs
→ Continue: Movement to Case Fit
ETA 6497
Diameter: ~36.6 mm
Height: ~4.5 mm
Large-format manual movement defining oversized cases.
→ Use for: large diameter, manual-wind architecture
→ Continue: Movement to Case Fit
Selection Principle
Movement selection is governed by physical constraints, not preference.
Selection must consider:
target case diameter
target case thickness
movement type (automatic or manual)
intended case architecture
Each movement defines a fixed design envelope.
There is no interchangeable solution.
System Integration
Movement selection is the entry point to the case design system.
Once selected, proceed immediately to:
Movement to Case Fit
This step converts movement parameters into a usable case geometry and leads directly into:
Radial Clearance
Axial Clearance
Internal Case Geometry & Movement Cavity Sizing
Final Statement
Movement selection defines the entire case architecture.
A valid design must:
begin with a fixed movement
derive all geometry from that movement
maintain consistency throughout the system
If the movement is not defined, the case cannot be engineered.
Next Step
Select your movement and continue the system.
→ Movement to Case Fit
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