SOSHH® Stainless Steel Snap-In Spigots | SS304 / SS316L Weld-On Spigots for Flexible Connectors

Pricing depends on diameter, height, stainless-steel grade, quantity, surface finish and custom geometry. Prototype quantities and OEM production orders are supported.

SOSHH® stainless steel snap-in spigots are precision-formed rigid interfaces for compatible snap-in flexible connectors used on vibrating sifters, screeners, feeders, hoppers, dosing systems and powder-processing equipment. Standard construction uses AISI 304 or AISI 316L stainless steel with a nominal 2.0 mm wall thickness, with 50 mm compact and 90 mm extended height configurations.

The spigot provides the rigid seating geometry for the flexible connector cuff. Proper compatibility depends on the actual spigot outside diameter, inner bore, groove/profile and installation conditions. For replacement and retrofit projects, SOSHH can review existing dimensions, drawings or photographs and provide a matched spigot and flexible connector specification.

Standard diameter references extend from Ø102 to Ø804 mm, with custom diameters, heights, wall thicknesses, surface finishes and geometries available for OEM and retrofit applications.

Installation Instructions: Permanent Spigot Welding

Select the corresponding size of the steel spigot based on the outer diameter of your on-site equipment or piping, and proceed to weld both ends in sequence.

Step 01: Measure Outer Diameter (OD)

Accurately measure the exact outer diameter of your existing rigid pipe to select the matching SOSHH spigot size.

Step 02: Align & Weld First Spigot

Position the steel spigot coaxially over the pipe. Apply a full-perimeter TIG (Argon-arc) weld to ensure a secure, airtight seal. The 2mm wall thickness prevents burn-through.

Step 03: Weld Opposing Spigot

Align and weld the second spigot to the opposing pipe, paying close attention to the vertical alignment.

Step 04: Verify Installation Gap (IG)

Once welded, check that the correct Installation Gap is maintained between the two spigot heads. The system is now ready for the tool-free snap-in of the flexible PU sleeve.

Installation Instructions: Tool-Free PU Sleeve Snap-In

Step 01: Compress the Snap-Band
integrated elastic snap-band... gently fold the ring into a C-shape for easy insertion.

Step 02: Seat the Lower Band
Insert the compressed band into the lower welded steel spigot. Release your grip, allowing the band's elastic memory to snap it firmly into the internal locking groove.

Step 03: Seat the Upper Band
Repeat the exact same folding process for the top snap-band. Push it upward into the internal groove of the upper steel spigot and release.

Step 04: Perfect Hygienic Seal
The flexible sleeve is now fully installed. The outward radial tension of the snap-bands ensures a 100% dust-tight, flush, and crevice-free seal that resists high vibration and pressure.

1. Why the Spigot Is the Foundation of a Dust-Tight Seal

Why the Spigot Is Critical to a Reliable Flexible Connector Interface

A snap-in flexible connector depends on a correctly formed rigid spigot for reliable mechanical engagement. The spigot controls the seating geometry of the connector cuff and influences alignment, retention, hygiene and service life. Common interface problems include: incorrect outside diameter excessive ovality damaged or poorly finished seating surfaces weld spatter or sharp internal edges incorrect installation gap mismatch between the connector cuff and spigot profile SOSHH therefore recommends specifying the spigot and flexible connector as a matched interface, particularly for vibrating equipment, food-processing lines, vacuum service and retrofit applications.

2. Core Engineering Specifications & Compliance

• Structural Metallurgy: AISI 304 (1.4301) for dry food powders and bulk solids; AISI 316L (1.4404) for pharmaceutical API synthesis, high-chloride media, and hot caustic CIP washdowns.
• Internal Surface Finish: Standard 2B mechanically polished to Ra ≤ 0.8 µm (32 µ-in); electro-polished to Ra ≤ 0.4 µm (16 µ-in) for sterile sanitary suites.
• Wall Thickness: 2.0 mm structural gauge — engineered for high-integrity manual or orbital TIG (argon-arc) butt-welding.
• Machining Tolerances: Precision turned and rolled to ISO 2768-m.
• European Regulatory Framework: Fully compliant with European Regulation (EC) No 1935/2004 for materials intended to come into contact with foodstuffs.
• Explosion Safety (ATEX): Passive metallic piping component. When earth-grounded, it provides electrical continuity across the flexible joint. Pair with SOSHH static-dissipative sleeves (PU-10-AS or Anti-Static PTFE, surface resistivity < 10⁹ Ω) for ATEX Zones 20, 21, and 22.
• Material Traceability: EN 10204 Type 3.1 Inspection Certificate supplied with chemical batch analysis and mechanical test properties.

3. Spigot Anatomy & Tapered Sealing Principle

• The Head (Locking Groove): The precision-formed upper section featuring an internal rolled channel and a calibrated outward taper. When the flexible sleeve cuff snaps over the rim, this taper generates progressive radial tension — the farther the cuff seats, the tighter it grips under 20–30 Hz continuous vibratory screening.
• The Tail (Weldable Extension): The straight lower cylinder designed for on-site butt-welding to process pipework. It can be trimmed on site to fit tight vertical dimensions (the 90 mm extended model provides extra cutting allowance).
• The Installation Gap (IG): The vertical distance between opposing spigot heads after welding. A verified IG keeps the sleeve under the designed mechanical tension to absorb vibration without tensile stress or S-bend buckling.
• Hygienic Execution: Supplied with a solid, uninterrupted sanitary rim (zero-hole default) to prevent bacteria build-up during CIP. An optional 6 mm release hole can be machined on request for tooling conversions.

4. Part Number Decoder — Read Any Spigot Instantly

Standard part numbers encode complete engineering parameters in one code:

SF - {Outer Diameter D} - {Head Height H} - {Material M}

• SF: Snap-Fit sanitary stainless steel spigot
• {D}: Outer diameter in mm (matches the flexible sleeve seating diameter)
• {H}: Head height (50 = 50 mm compact; 90 = 90 mm extended)
• {M}: Steel grade (304SS = AISI 304; 316L = AISI 316L)
• Inner Diameter Rule: d = D − 4.0 mm (based on 2.0 mm wall thickness × 2)

Part Number Examples:

• SF20450316L: Ø204 mm OD, 50 mm compact head, AISI 316L (Inner bore = 200 mm)
• SF25490304SS: Ø254 mm OD, 90 mm extended head, AISI 304 (Inner bore = 250 mm)
• SF10290304SS: Ø102 mm OD, 90 mm extended head, AISI 304 (Inner bore = 98 mm)

5. Series A — 50 mm Height Standard Spigots (Complete 21 Sizes)

Optimized for compact vertical clearances, short hopper chutes, and standard vibratory sifter inlets and outlets.

Important: Spigot ID and flexible-sleeve reference diameter are not the same dimension. The spigot OD identifies the seating interface; the spigot ID is the internal bore after allowing for the 2.0 mm wall. Always select the sleeve using the actual compatible spigot profile.

6. Series B — 90 mm Height Extended Spigots (Complete 21 Sizes)

Recommended when a larger Heat-Affected Zone (HAZ) welding buffer is required or when trimming the tail on site.

Custom CNC Machining: Intermediate diameters (e.g., Ø133 mm, Ø168 mm) and diameters up to Ø1000+ mm are fabricated with zero tooling fees. For full crossover combinations, view our Standard Size Database.

7. Metallurgy Selection Guide: AISI 304 vs. AISI 316L

Material selection should be based on the actual process media, cleaning agents, temperature, chloride exposure and plant specification.

8. On-Site Installation & Welding Protocol

1. Step 01 — Measure Pipe Dimensions: Accurately verify the outside diameter and roundness of the existing pipe using vernier calipers or a Pi tape.
2. Step 02 — Align & Tack Weld: Position the spigot weld tail coaxially against the pipe end. Check concentricity and place 4 quadrant tack welds. The 2.0 mm wall prevents heat burn-through.
3. Step 03 — Full Penetration TIG Weld: Complete a continuous argon-shielded TIG weld around the circumference. Grind and passivate internal weld beads flush (≤0.8 µm Ra) to prevent powder accumulation.
4. Step 04 — Verify Installation Gap (IG): Confirm the vertical face-to-face gap between opposing spigots matches the engineered sleeve length before snapping in the flexible connector.

9. Tool-Free Snap-In Flexible Connector Installation

Step 1 — Compress the Cuff Fold the flexible connector cuff inward according to the connector installation instructions.
Step 2 — Seat the First Side Position the cuff evenly around the compatible spigot seating profile.
Step 3 — Release and Check Seating Allow the integrated snap-band to engage the spigot profile, then inspect the full circumference to confirm even seating.
Step 4 — Repeat on the Opposite Side Install the second cuff using the same procedure.
Step 5 — Final Inspection Check that the connector is evenly seated, aligned and free from visible folds, twists or partial engagement.

When correctly matched and installed, the snap-in interface provides a secure, hygienic and dust-containing connection without an external hose clamp. Actual pressure, vacuum and vibration suitability depends on the selected connector construction and operating conditions.

10. Pair Your Spigot: Recommended Sleeve Combinations

11. Frequently Asked Questions (FAQ)

Q1: What is the mechanical difference between a spigot and an ordinary pipe stub?

An ordinary pipe stub lacks the precision-turned internal locking groove and calibrated outward taper required to lock a snap-in band. The SOSHH spigot provides the exact channel geometry and surface finish required to guarantee a dust-tight seal under continuous vibration without hose clamps.

Q2: Should I select the 50 mm or 90 mm height?

Choose 50 mm (Compact) for short vertical spaces, vibrating screeners, and tight equipment transitions. Choose 90 mm (Extended) when orbital welding creates a wider Heat-Affected Zone (HAZ) or when on-site pipe trimming requires extra tail cutting allowance.

Q3: How is food contact compliance certified on metal spigots?

FDA 21 CFR 177.2600 applies specifically to rubber and polymeric materials (such as TPU sleeves). Stainless steel spigots are certified under European Regulation (EC) No 1935/2004 for materials intended to come into contact with food, supported by authentic EN 10204 3.1 inspection test certificates.

Q4: Are your spigots individually ATEX certified?

As passive metallic piping components, stainless steel spigots do not fall under separate ATEX equipment directives. For ATEX Zone 20, 21, and 22 compliance, earth-ground both spigots and install an anti-static flexible sleeve (such as PU-10-AS or Anti-Static PTFE).

Q5: Can I request 3D CAD models before ordering?

Yes. STEP and DXF CAD models are available for engineering design verification. A standard NDA / NNN (Non-Disclosure / Non-Circumvention) agreement is required prior to digital file release.

Q6: What does the d = D − 4 mm rule mean for plant piping?

The 2.0 mm structural wall reduces the inner bore diameter by 4 mm relative to the outer seating diameter D. If your line requires a continuous bore with zero reduction, contact our engineering desk for custom-machined transitional tails.

Q7: Can you manufacture spigots to fit non-standard pipe diameters?

Yes. Our CNC workshop machines custom wall thicknesses, extended lengths, and intermediate diameters (e.g., Ø133 mm, Ø168 mm) with zero tooling fees.

Q8: Do I need a release hole on the spigot rim?

By default, SOSHH spigots are supplied with an uninterrupted zero-hole rim to preserve a crevice-free sanitary sealing face. A 6 mm release hole is an optional modification for plants utilizing specialized disassembly tools.

Q9: What spigot size corresponds to a 250 mm-class connection?

On the standard SOSHH geometry, a Ø254 mm spigot has a nominal Ø250 mm internal bore. The correct flexible connector reference is selected from the actual spigot seating geometry.

Q10: What spigot size corresponds to a 350 mm-class connection?

A Ø354 mm spigot has a nominal Ø350 mm internal bore.

Q11: What spigot size corresponds to a 600 mm-class connection?

A Ø604 mm spigot has a nominal Ø600 mm internal bore.

Q12: Can you manufacture a 250 × 150 mm or 250 × 350 mm flexible connector system?

Yes. SOSHH supports custom connector lengths. For 250 mm-class applications, the standard spigot reference may be Ø254 mm; the final interface should be verified before production.

Q13: Can I order only the stainless-steel spigot?

Yes. Spigots can be supplied separately or as a matched spigot + flexible connector system.

Q14: Can you manufacture a custom spigot from my drawing?

Yes. Custom diameter, height, wall thickness, tail length, geometry and surface finish can be engineered from a customer drawing or existing-part sample.

Q15: Can you provide 2D and 3D CAD?

Yes. PDF/DXF/STEP files can be provided where applicable for engineering review.

Q16: Can I request SS304 or SS316L?

Yes. Both grades are available; selection depends on process media, cleaning chemistry and plant requirements.

Q17: Is a 50 mm spigot available for short-clearance applications?

Yes. The 50 mm compact configuration is intended for applications where vertical rigid height is limited. The actual installation gap should be verified together with the selected flexible connector.

Q18: Can you supply the connector for ATEX Zone 22?

SOSHH can supply anti-static connector configurations and the corresponding spigot interface. Final suitability must be assessed for the complete assembly and installation according to the site hazardous-area requirements.

12. Request a 2D Drawing & Fast Quotation

Submit your piping connection parameters to our engineering desk for 24-hour verification:

• [ ] Required Outer Diameter D: Seating channel outer diameter (mm)
• [ ] Head Height: 50 mm Compact or 90 mm Extended
• [ ] Stainless Steel Grade: AISI 304 or AISI 316L
• [ ] Target Quantity: Prototype testing or production run (pcs)
• [ ] Matching Sleeve Requirement: Sleeves needed in the same shipment