GD&T Symbol Guide
Spotface
Defines a shallow flat-bottomed cylindrical cleanup area around a hole.
Definition
A spotface is a shallow flat-bottomed cylindrical feature coaxial with a hole.
It creates a flat seating surface without necessarily recessing the fastener head like a counterbore.
Application
Use it for washer seats, pan head screws, or cleanup pads on rough cast or forged surfaces.
The spotface callout includes the symbol, the spotface diameter, and depth only when a depth is required.
Spotface Drawing Use
Spotface is read with the adjacent dimension, note, or feature control frame so inspection uses the intended feature definition.
3D Tolerance Zone
This symbol defines or modifies a size, shape, or manufacturing dimension rather than creating a GD&T tolerance zone by itself.
Inspection Method
Read the symbol with the attached dimension, note, or feature control frame before evaluating the feature.
Verify the controlled feature using the drawing's stated limits, datum setup, and any special notes tied to the symbol.
Worked Read: Spotface
A drawing includes the Spotface symbol with a related feature requirement.
Identify
SF
Recognize the Spotface symbol and the feature it modifies.
Read
Adjacent value
Use the attached dimension, note, or frame cells as the controlling requirement.
Inspect
Per drawing
Measure the named feature using the specified interpretation rather than assuming a generic size check.
Spotface clarifies how the feature is defined so the drawing and inspection method stay aligned.
Comparison Table
| Item | Controls | Typical Placement |
|---|---|---|
| Spotface | Dimension interpretation | Next to a dimension, note, or frame |
| GD&T control | Geometric variation | Feature control frame |
| Datum reference | Measurement setup | Datum feature or frame cell |
Notes
This page is part of the drawing-symbol reference set rather than a standalone geometric tolerance category.
When the symbol modifies a feature control frame, read it together with the tolerance value and datum references.