A continuous sealing land.

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.

R4 separates the mated seal from the longitudinal keyways. The plug spigot now extends to Z36, its gland is centered at Z33, and the receiver has a continuous mating land over the gland. The original seal groove is filled. The dielectric support has a smaller forward nose so it clears the extended spigot while maintaining the existing contact positions. A tapered receiver entry provides an initial lead-in.

The complete STEP retains 457 separate cable/connector solids. Its source rebuild matches every solid. The inspection view shows the receiver translated45 mm and the dielectric85 mm for explanation; these are exploded poses, not an installation demonstration.

Nominal gland geometry

The seal is a constant-volume elliptic occupancy model , not a simulated rubber deformation or exact purchased O-ring. It preserves the nominal free-ring volume while fitting the radial gland height. Supplier ID/stretch effects, compound, hardness, actual dimensions, swelling and temperature must still be selected and evaluated.

Design reference and unresolved tolerance result

Trelleborg's June2024 O-Ring catalog, Table23 on page59, gives1.10 mm static radial housing depth for a1.50 mm cross-section, with2.00 mm groove width and a positive width allowance. Its groove-fill discussion on page54 recommends staying at or below85%; the footnote on page61 says the tabulated depths do not account for inside diameter and stretch. These are reference inputs, not Subfield qualification. Manufacturer catalog .

A64-case sensitivity study using explicitly illustrative tolerances reaches 85.5885% maximum fill , above that recommendation. The cases use custom radial±0.02 mm, width±0.05 mm, corner±0.02 mm, seal cross-section±0.05 mm and free ID±0.20 mm. These are not selected supplier tolerances. See tolerance-sensitivity.json for the exact worst combination. This revision is not tolerance-qualified. The next step is to select the seal/compound and resolve groove width, actual seal tolerances, stretch and swelling allowance together.

The seal still crosses keyway openings during insertion before reaching its continuous final land. Lead-in geometry alone does not prove damage-free mating. That service path, edge finishing and lubrication/contamination compatibility need development and testing. No immersion, pressure, gas-tightness or electrical rating follows from the nominal fit.

Verification and files

957 nominal geometry checks and two focused tests pass. Both rigid-part clearance and continuous mated land are checked. The STEP reimports with457 valid solids, and a copied-source rebuild matches all457 by individual Boolean symmetric difference. The native render was reopened and its four visible CAD meshes verified within0.001 mm. The full repository regression is running as session12127.

complete-termination.step — integrated cable and connector.

inspection.blend / inspection.png — native exploded interface view.

source/ — editable source and locked dependencies.

record.json — nominal geometry evidence and limitations.

tolerance-sensitivity.json — unresolved tolerance study, preserved independently of nominal passes.

Retaining-ring installation, actual vendor geometry, bayonet detent/preload, stud anchorage, contact termination, jacket sealing/anchorage and complete environmental/electrical qualification remain open. This is a construction-development revision, not a manufacturing release.