DSS-M.01.02 — Straightedge / Metal-Guide Scoring

Long, ruler-straight linear score(s) produced when a scraper/razor or other hard edge rides along a metal straightedge/guide on the glass face. Typically presents bright “chip flanks” / micro-chipping along the line in raking light; persists after reveal and does not behave like a residue film. Terminology for micro-chipping and chip flank per VIS §3; classification is appearance-based using surface-catch and morphology under VIS viewing conditions.

• Ruler-straight tracks across part or all of the lite; often parallel multiples (repeat passes along the guide).
• Sparkling flanks in raking light from edge breakout; consistent line width/depth compared to hand-free scratches.
• Persists after Non-Invasive Reveal (clean & dry); does not wipe off.

Surface-catch class (MSRT):

• Commonly SC-2 (clear) for true guide-assisted scores; shallow grazes may read SC-1 (slight). One light, non-marring pass only; MSRT supports classification, not acceptance.

Reveal / lighting / geometry:

• Complete Non-Invasive Reveal (distilled/neutral-pH water; lint-free microfiber; no blades/abrasives/chemicals prior to evaluation). Inspect at 12 / 36 / 72 in, normal incidence + oblique sweep (~60°-120°) with raking light, per VIS.

Location / access:

• Confirm the cue is on the exposed face (not between panes). If any doubt, use parallax (between-pane features show fixed parallax) and record surface numbering #1-#4 on Forms:

Assign CAT by visibility convention and MSRT outcome under VIS inspection-use chip-flank severity to distinguish depth bands:

• CAT-2 - Light: Narrow, clean-edged line(s) with SC-1, no pronounced chip flanks; limited impact at standard view.
• CAT-3 - Moderate: SC-2 with minor chip flanks; noticeable at standard distance.
• CAT-4 - Severe: SC-2 (clear-to-strong) with rough chip flanks, possible pits/craters; distinctly visible at standard and wide-field views.

(Use the VIS three-part cueing: surface catch + edge/surface morphology + location/access.

• CAT-2: ~0.2-1 μm typical surface incision (clean edges; minimal flank breakout).
• CAT-3: ~1-5 μm with incipient micro-chipping along flanks.
• CAT-4: ≥5 μm with rough chip-flank breakout; local pits/craters may be present.

(Depths are illustrative for cueing only; VIS classification/acceptance remains appearance-based.)

• vs. Scraper/Razor scoring (M.01.01): Hand-free scores often show arcs/variable directionality; guide scores are ruler-straight with consistent depth and may have parallel repeats.
• vs. Glass-on-glass tracks (M.01.03): Tracks commonly present paired arcs/lines with travel-path periodicity; guide scores are single or parallel straight runs.
• vs. Coating anomalies (Co-family): Coating rub/patch/colour shifts are area-based, generally SC-0/SC-1, and lack chip flanks; coating anomalies on worked faces are not permitted at acceptance.
• vs. Between-pane cues (A-family): Internal features show fixed parallax → CAT-5 by location.

• Photo set (VIS): 12 / 36 / 72 in, normal + oblique, include raking; add macro frames of the line showing chip flanks (no worked transition edge). Consider one context photo showing ruler-straight alignment (include a straightedge in frame when appropriate). Note reveal status and lighting/time.
• MSRT result: Record SC class (often SC-2); one pass, non-marring.
• Forms: Pane ID; surface numbering; worked surface Y/N; geometry checklist; photos attached (per VIS Appendix X3 fields).

• Attempting to “feather” a straightedge score during inspection can create a worked region/transition edge, which VIS disallows at acceptance for CAT-0...CAT-4. Keep evaluation non-marring and appearance-only.

• M.01.02 Straightedge/Metal-Guide Scoring - Ruler-straight linear line(s) at #__ with chip-flank sparkle in raking; MSRT = SC-1/SC-2. Persists after Non-Invasive Reveal. Classified CAT-2/3/4 by visibility and flank severity per VIS. Photo set at 12/36/72 in (normal + oblique + raking); surface numbering and form fields recorded. Acceptance per VIS §6 (appearance-based).