Core Rear Mount R8.

Research record

The detail behind
the study.

Source-linked work for this revision. Reported checks describe the stated model or test; physical qualification and applicability to the current retrofit remain separate.

The 81-part concept assembly increases keyhole entry diameter from 8.6 to 9.0 mm, slot width from 4.6 to 5.0 mm and stud neck length from 4.3 to 4.7 mm. The changes address the R7 prototype-fit budget shortfall while retaining the 12 mm lift / 25 mm outward removal path and captive anti-lift screw.

With the same proposed tolerance/coating budget, entry and slot radial clearance each increase from 0.085 to 0.285 mm; total axial throat clearance increases from 0.05 to 0.45 mm. These exceed the proposed 0.10 mm radial and 0.20 mm axial targets. The head moves 0.4 mm toward the wall, leaving 1.8 mm nominal head-to-wall clearance. This budget covers only three local fits, not global form/alignment, contamination, thermal expansion or load deflection. Supplier capability and the coating process remain unqualified.

Two focused tests passed in 79.43 seconds. Nominal fit/export, release/capture motion and compartment checks passed. Stud heads still reject a pull without the required lift. Full CAD regression for R8 passed: 334 tests in 1538.36 seconds. This does not cover R9. A standalone source copy in a separate locked dependency environment reproduced all 81 STEP bodies with zero Boolean symmetric difference.

No manufacturing release is claimed. Materials, wall anchors, threaded strength and anti-loosening, clip elasticity, carrier fabrication, tolerances for the rest of the enclosure, physical assembly/handling, weathering, electrical components, wiring and qualification remain unfinished. R7 drawings are historical and do not describe the changed R8 stud or slot dimensions. The R8 review sheets cover these interfaces, but are not complete production drawings for all enclosure parts. Prototype assumptions must not be mistaken for production specifications.

The current R8 carrier is not defined as a fabricable sheet-metal part. Actual STEP measurements find a 4 mm main ring and a 3 mm return web/foot in one solid. The return's tested inside corner is sharp. There is no defined bend, relief, weld or assembly joint.

This leaves a fabrication decision, not merely a missing file export. A uniform-thickness flat pattern cannot reproduce this exact solid. Select and model the intended route: a formed construction with consistent sheet thickness and qualified bend details, or a separate return with its joint explicitly designed and checked. An alternative subtractive route needs its own tool-access and corner treatment review.

The local bounding prism is 334 x 601 x 24 mm (4,817,616 cubic mm), while the modeled part volume is 113,536.40 cubic mm, or 2.36% of that prism. This comparison shows the extent of empty space; it is not a stock selection, cost estimate or machining approval.

The JSON contains source hashes and three thickness witnesses plus the inside-corner checks. This finding does not change R8 geometry or invalidate its nominal clearance checks. It does prevent describing the current carrier as ready for sheet fabrication. Material, process, joint strength, tolerances and physical qualification remain open.