DSS-M.03.04 — Edge “Shelling” at Hardware Holes/Slots

Edge “shelling” at hardware holes/slots is a localized shell-type loss that originates at the perimeter of a drilled hole or machined notch and intrudes onto the exposed face. It is distinct from a factory exit-lip (a uniform burr confined to the hole/slot perimeter that reads SC-0 on the face and is not damage). Classification here is appearance-only per VIS; restoration methodology is out of scope. Inspect under VIS lighting/geometry and record surface numbering and worked-surface status on Forms:

• Crescent/shell-shaped losses or ragged “bites” breaking from the hole/slot perimeter onto the face; often brightest in raking light.
• May include short chip flanks and micro-cracking radiating from the penetration.
• Common at hardware landings (standoff holes, spider fittings) or notch roots. (Use VIS oblique sweep and raking light.)

Surface-catch class (MSRT)

• Expect SC-2 (clear) where shelling intrudes onto the face. Perform one light, non-marring pass only per VIS §5.5; do not abrade or “probe.” Prefer a polymer stylus on suspected coated faces; MSRT supports classification, not acceptance.

Visual signature

• Bright, rough chip flanks at the penetration edge with discrete shell geometry; distinguish from a uniform exit-lip that is edge-confined and SC-0 on the face.

Viewing / lighting

• After Non-Invasive Reveal (clean & dry), evaluate at 12 / 36 / 72 in, normal incidence and oblique sweep (~60°-120°) under raking light.
• Location / access Record pane ID and surface numbering (#1-#4; laminate-internal) on Forms: If fixed parallax proves a between-pane look-alike or the defect is otherwise inaccessible, record CAT-5 and refer.

Assign CAT by appearance + MSRT + morphology (three-part cueing under VIS). Depths below are indicative to anchor the spectrum:

• CAT-2 → low CAT-3 (lower bound): Small, shallow shells just breaking onto the face; SC-1-SC-2; primarily a raking-light cue at close/standard view. Indicative depth: ~10-40 μm.
• CAT-3 (typical): Pronounced shelling with clear catch and bright, rough chip flanks; noticeable at standard view. Indicative depth: ~40-120 μm.
• CAT-4 (upper bound): Deep/extended shelling with secondary pits/craters and/or short cracks propagating from the penetration; strong catch; clearly visible at standard & wide-field views. Indicative depth: ~120-300 μm+.
• CAT-5 (by location/condition): Between-pane/inaccessible or integrity indicators (active cracks, moving pane) → out of in-place scope; document and refer per project protocol.

CAT assignment is appearance-based under VIS; acceptance is separate (VIS §6).

• vs. Factory drill/slot exit-lip (P.03.04): Exit-lip is a uniform burr confined to the hole/slot, reads SC-0 on the face, and shows no chip-flank morphology. Do not classify as damage.
• vs. Linear scoring (M.01): Scoring forms extended lines across the face; an exit-lip/shelling is peripheral to a hole/slot. If scoring is present, classify under M.01 in addition.
• vs. Coating anomalies (Co.01/Co.03): Worked-face coating rub/patchiness is disallowed at acceptance on coated faces (VIS §6.2.e); shelling shows fracture morphology at a penetration.

• Photo set (VIS): 12 / 36 / 72 in, normal + oblique, with raking macros of the penetration edge showing chip flanks and at least one context frame proving the condition breaks onto the face (i.e., not just an exit-lip).
• MSRT result: Record SC class (SC-0/1/2 as observed). One pass, non-marring; prefer polymer stylus on suspected coated faces.
• Forms: Pane ID; product family & surface numbering; worked surface Y/N; functional coating on worked surface? (Y/N/Unknown); reveal status; lighting/time; geometry checklist; photos attached.
• Acceptance split: VIS governs post-restoration appearance. Do not conflate a factory exit-lip with face-side acceptance; if a worked region is created, transition edges remain disqualifying at acceptance for CAT-0...CAT-4.

• M.03.04 Edge “Shelling” at Hardware Hole/Slot - Discrete shell-type loss breaking from [hole/slot] perimeter onto the exposed face #___. MSRT = SC-2 (clear) at shell perimeter; bright, rough chip flanks present. Visible at [12/36/72 in] under VIS geometry. Classification: CAT-[3/4] by morphology + MSRT. Differentiation: not a uniform exit-lip (SC-0 on face). Acceptance: per VIS §6; documentation attached (photo set + forms).