Wall-mount stud slots — coverage, hardware, material

kerfmaster pin list · The spec — what we build to

rulingA decision by Aristide or Jordan. True because it was decided; it can be superseded, but it cannot be stale.

Content last changed 2026-08-09 — computed from the item itself, not typed.

Aristide, 2026-08-08 — the stud-slot rules, stated as generalizations (closing gaps found while framing the fresh-agent test):

• Coverage: two rows of slots, overlapped/staggered so that wherever a stud is, one of the slots will always line up — at any lateral offset of the template on the wall.
• Both stud pitches: the slots must accommodate 16" and 24" on-center framing. Slot width and the spacing between slots are the design variables that carry this requirement; the layout math is derived, not stated.
• Bolts: stud slots always take 1/4" lag bolts.
• Hardware set: we create the slots; 1/4" lag bolts; the customer-provided zip ties (the 2.5 mm strap already in the tables); 1/8" steel.
• Placement (Aristide, 2026-08-09, from the option-C teaching file): stud slots live ONLY in metal that is never seen — a hidden template plate, or on a flat-to-wall build the regions the raised elements cover (the never-seen map is the fixing budget). An option whose mount is a hidden template or pins carries NO slots in any visible plate; a build whose never-seen metal cannot take the slots does not get visible slots as a "disclosed tradeoff" — it gets a different mounting, or the constraint is reported ([[mvt-cloud-fixing]] is the worked example). Cutting stud slots through a finished face is a defect, not an economy option.

Like the placement rulebook: these are requirements, not a drawing. Any layout that provably meets them is legal; the proof (coverage at every offset, both pitches) belongs on the shop sheet. The worked proof exists (measured 2026-08-09): Aristide's option-C file carries it — slot 1.08", pitch 1.33" (under the 1.5" stud face, so each row alone catches every stud), rows staggered so each row's gaps are covered by the other with margin: union coverage continuous, both-rows-per-stud at every offset ([[mvt-option-c-file]]). The mechanism generalizes: pitch under the stud face width; stagger the second row so its slots cover the first row's gaps.

Completed 2026-08-08 (Aristide):

• Slot height 5/16" for the 1/4" lag bolt — bolt plus 1/16 clearance.
• Engagement (Aristide, 2026-08-08 — clarifies, supersedes "two studs at every offset"): the requirement is the SLOT MATH — slot width and slot spacing chosen so the pattern WORKS at both 16" and 24" OC: every stud that falls behind the template is caught, at any lateral offset. Engage every stud available — two when the geometry offers them (on 30" art it does at many positions) — but two-at-every-offset is not forced: guaranteeing two at 24" OC takes 48" of slot span, which small art cannot carry. Anti-rotation is carried by BOLTS, not stud count: minimum two lag bolts always; when only one stud is reachable, the two rows put both bolts into that stud as a vertical couple. One bolt lets the sign rotate.
• Row placement (REWRITTEN 2026-08-09 from the owner's option-C file — supersedes the earlier "as far apart as the template allows", which was the kit's own error, not the owner's rule): slot rows come as FIELDS of TWO rows 0.60" apart. The close pair is the vertical bolt couple — both lags into the same stud; anti-rotation lives INSIDE the field, not in spreading rows to the template's extremes. A wide template takes its width in MORE fields (the owner's file carries several), never by stretching one pair apart. No row sits closer to an edge than the web minimum.
• Catch window (added 2026-08-09, from the round-3 failure): the horizontal slot span plus the 1.5" stud face must EXCEED the largest pitch served — span + 1.5 > 24 for 24" OC — otherwise lateral offsets exist where NO stud falls behind any slot and the piece is unmountable there (round 3 drew span 5.25–23.62 → window 19.9" < 24 → ~4.6" of offsets with zero bolts). Prove it by sweeping offsets per pitch; the sweep result is a shop-sheet claim.
• Edge web at a slot: the teaching sheet's slot QC ran at 0.40"; use 0.40 for load-bearing slots, 0.20 absolute floor (see [[fastener-holes]]).

Self-QC (added 2026-08-09, from the round-2 blind test; extended after round 3): after ANY slot is moved or added, re-run (a) contour clearance — no two cut contours may approach closer than the non-adjacent web floor (proposed 0.40", pending Jordan) UNLESS they are adjacent slots of the same designed row: the in-row gap is a DESIGN value, not a QC floor — the owner's own file cuts 0.25" between in-row slots; the floor exists to catch features that were never designed together drifting into each other. Two contours that intersect are an automatic FAIL, never shipped; (b) the edge-web audit against the final outline; (c) the coverage sweep; (d) a polyline census of our OWN output — zero polylined curves in anything we emit; a curve standing as hundreds of LINE segments in our own DXF is the exact defect cadmaster exists to undo (round 3 shipped a template outline as 4177 LINE segs); (e) per-plate tie-pair verification — for every tie pair, both holes sit at the ladder webs in their OWN metal, and the hidden hole is actually BACKED by hidden metal (a pair with no template behind it fastens nothing). The claims on the sheet are RE-GENERATED from the final geometry, never carried forward from the layout that preceded the fit. This clause is general: it applies to every adjusted geometry, holes and marks included — round 2 built the right architecture and then shipped two intersecting slot pairs and a 0.112 web against a claimed 0.15, all because nothing forced a re-measure after the stage-2 shift.