Wood products — In construction documentation and shop practice, is it accurate that the visible surface of a wood member is finished by milling or planing to achieve the specified smoothness before any coating?

Introduction / Context:
Wood members in buildings and millwork pass through primary sizing and surface preparation steps. Milling and planing produce dimensional accuracy and smoothness, forming the basis for appearance, fit, and subsequent finishing such as sanding, sealing, staining, or painting. The question asks whether planing/milling constitute the finishing of the surface in the sense of preparing the visible face.

Given Data / Assumptions:

• Wood elements include solid lumber and some engineered products.
• “Finished surface” refers to the prepared face as supplied or before coatings.
• Additional sanding and coatings may follow milling/planing.

Concept / Approach:
Planers and milling machines remove irregularities, flatten faces, and produce uniform thickness, creating a smooth surface suitable for installation or finishing. While final appearance may require sanding and coatings, the essential finishing of the raw surface is achieved through milling/planing, which is why lumber is often graded surfaced on one or more sides (e.g., S4S).

Step-by-Step Solution:
1) Identify surface preparation tools: planer and milling cutters.2) Recognize their objective: smooth, dimensionally accurate faces.3) Relate to documentation: drawings/specs call for planed/milled finishes prior to any coatings.4) Conclude the statement is correct.

Verification / Alternative check:
Material takeoffs and millwork schedules often specify surfaced grades or machining marks such as “S4S” (surfaced four sides), indicating planing/milling as the finishing basis for visible faces.

Why Other Options Are Wrong:

• Incorrect: Conflicts with standard woodworking process flow.
• Engineered wood only / softwoods only / stained only: Planing/milling are applicable across species and finish types.

Common Pitfalls:
Confusing planing with sanding or coating; assuming rough-sawn faces are acceptable where smooth finish is required; omitting notes in drawings regarding visible face requirements.

Final Answer:
Correct