SMS-13RBN Sanitary Slotted Round Blind Union Nut with Chain in SS304 / SS316L

Component Role & Tethered Blind-Cap Geometry

The SMS-13RBN blind union nut is a closed-end slotted round nut designed to cap off an externally threaded SMS-15 union male port without requiring a separate blank disc and open nut. As shown in the dimensional schedule, its solid outer face features a centered boss fitted with a stainless steel retaining chain so the cap remains tethered to the line during washdown or sampling.

Material Grades, Surface Finish & Dimensional Scope

Manufactured in SS304 and SS316L stainless steel with a surface finish rated at Ra < 0.8 um in the series specification schedule, the SMS-13RBN series spans 25 mm to 104 mm in the page summary and tabulates eight sizes in the dimensional schedule: 25, 32, 38, 51, 63.5, 76.1, 101.6 (Max), and 101.6 (Min). Across these rows, outer diameter A runs from 51 mm to 154 mm, internal knuckle thread B progresses from Rd40×1/6" to Rd132×1/6" (101.6 Max) and Rd125×1/4" (101.6 Min), and total height H (including boss) spans 27 mm to 39 mm.

101.6 mm Thread Variants & Ordering Notes

Pay particular attention to the two 101.6 mm variants in the dimensional schedule: 101.6 (Max) uses Rd132×1/6" threads with a 154 mm OD, whereas 101.6 (Min) uses Rd125×1/4" threads with a 140 mm OD. Confirm the mating SMS male thread specification and stainless steel grade when ordering.