Description
8" × 24" Round Manhole Frame & Cover
with Stainless Steel Security Bolts
SKU: AC-MH-824-SS | American Cast Iron Products, Inc.
Deep-frame cast iron access with corrosion-proof locking — engineered for septic, utility, and light-duty infrastructure applications.
Product Overview
Deep-Frame Round Access. Locked. Sealed. Built to Last.
The Amercast 8" × 24" Round Manhole Frame and Cover is a deep-frame cast iron access assembly precision-matched for septic systems, utility vaults, and light-duty infrastructure where a standard-depth frame simply won't reach. While the industry's common 4" and 6" frames suit shallow applications, this assembly's full 8-inch frame depth provides the extended reach needed to bridge grade adjustments, accommodate settlement, and seat cleanly within pre-cast concrete rings and risers used in septic and wet well construction.
What distinguishes this assembly from comparable offerings — including round frames in the Amercast manhole frame and cover catalog — is the inclusion of two (2) stainless steel security bolts as a standard component. Set 180° apart, these bolts lock the cover to the frame at the casting's machined seating surface, preventing unauthorized access, inadvertent displacement, and theft. Unlike plated or galvanized hardware found on lower-cost assemblies, the stainless bolts will not seize or corrode in the saturated, chemically active environments typical of septic systems and storm drainage infrastructure.
The cover and frame are cast from gray iron conforming to ASTM A48, Class 30B — the same specification used across Amercast's full manhole and grate product line — and shot-blasted to a clean, consistent finish. Bearing surfaces are machined for a firm, rattle-free seating contact. Castings are inspected to be free of gas holes, shrinkage, sand inclusions, and cracks before shipping.
Covers can be supplied plain or with cast-in markings — "SEPTIC," custom text, family names, company logos, or municipal identifiers. ADA-compliant cover patterns are also available. All custom configurations are quotable through Amercast's engineering team — typically with same-day response for in-stock items and standard configurations.
Technical Dimensions
Dimensional Reference — 8" × 24" Round Assembly
| Dim. | Description | Measurement |
|---|---|---|
| A | Outside Diameter — Frame | 24" |
| B | Frame Depth | 8" |
| C | Clear Opening (nominal) | ~18" |
| D | Cover Thickness | ~1" |
| — | Bolt Count | 2 × Stainless Steel |
| — | Bolt Spacing | 180° equidistant |
| — | Unit Weight (approx.) | ~65–80 lbs |
Dimensions are nominal. Foundry tolerances per the Iron Castings Handbook. Contact Amercast engineering for certified dimension drawings or project submittals.
Engineering Advantages
Why Contractors Specify This Assembly
Every design decision on this casting serves a functional purpose. From the depth of the frame to the choice of stainless hardware, this assembly is built for the environments where standard covers fall short.
8" Deep Frame — No Spacer Rings Needed
The extended frame depth eliminates the need for intermediate grade rings in most septic and utility installations, reducing labor costs and leak points.
Stainless Steel Bolts — Two Standard
Grade 316 stainless steel resists corrosion in H₂S-rich septic atmospheres, salt spray, and chemical environments where zinc-plated hardware fails within months.
ASTM A48 Class 30B Gray Iron
Minimum tensile strength of 30,000 psi ensures structural integrity for light-duty vehicle and equipment loads. The same specification governs Amercast's H20-rated products.
Shot-Blasted, Machine-Seated Surface
Bearing surfaces between cover and frame are cast and machined to prevent rocking, rattling, or settling under cyclic load — a frequent failure mode in lower-quality assemblies.
Custom Markings Available
Covers can be cast with "SEPTIC," "SEWER," company logos, family names, or ADA tread patterns at no minimum quantity. Submit your artwork with your quote request.
Foundry Dimensional Tolerances — ±1/16" per Foot
All Amercast castings are produced to dimensional tolerances per the Iron Castings Handbook (American Foundry Society) — nominally ±1/16" per foot, with unit weight verified within ±5% of drawing specification. Covers and grates shall not rock when rotated to any position in the frame, per AASHTO M306 seating requirements.
Two Finish Options: Natural or Black Bituminous Coating
Castings are available in your choice of finish. Natural (unpainted): the carbon and silicon in gray iron naturally develop a protective graphite layer and black oxide-silicate scale over time, providing inherent corrosion resistance — unpainted surfaces also bond more directly to surrounding concrete at installation. Black bituminous coating: a factory-applied black bituminous paint adds an immediate anti-oxidation barrier, inhibiting surface rust and providing additional protection in wet, saline, or chemically active environments such as septic and sewer applications. Specify your preferred finish when requesting a quote.
Applications
Where the 8" × 24" Round Assembly Performs
The combination of deep frame, secure bolt locking, and durable gray iron casting makes this product the go-to specification for access points that require containment integrity over the long service life of the structure.
Septic & Sanitary Systems
Ideal for residential and commercial septic tank access where H₂S exposure would corrode standard hardware. Bolts prevent odor escape and unauthorized access. Can be marked "SEPTIC" per standard practice.
Utility Vaults & Metering Pits
The 8" frame depth accommodates riser adjustment in pre-cast utility vaults and meter pits. Stainless bolts satisfy tamper-resistance requirements common in utility company access standards.
Private Driveway & Residential
Light-duty rating supports pedestrian and residential vehicle traffic. Round profile distributes load uniformly and eliminates the corner stress concentrations of square covers.
Pump Station & Wet Well Access
Deep frame handles grade transitions at pump stations without lifting rings. Bolted cover provides watertight-adjacent security during high-water events.
Irrigation & Landscape Systems
Non-corroding hardware withstands irrigation cycles and fertilizer exposure. Custom logo covers integrate cleanly into commercial landscape and golf course installations.
Standards & Compliance
Specification Compliance at a Glance
Amercast castings are produced under a quality management program at the foundry. Material certifications, mill test reports, and project-specific submittals are available for municipal, commercial, and government procurement requirements.
Field Reference
Installation Overview
This assembly is designed for straightforward field installation by standard construction crews. Follow project drawings and applicable municipal or septic authority requirements for bedding, cone seating, and final grade.
Verify Grade & Pre-Cast Ring Diameter
Confirm that the pre-cast concrete riser or cone opening accommodates the 24" O.D. frame. The 8" depth should be factored into the top ring elevation so the finished cover sits flush with final grade.
Bed the Frame
Set the frame into a full bed of hydraulic cement mortar or approved sealant around the full circumference of the frame base flange. Ensure frame is level and plumb before mortar sets.
Place the Cover
Lower the cover into the frame, seating it evenly on the machined bearing surface. The cover should seat without rocking. If rocking is observed, remove and re-check frame for level.
Install Stainless Steel Bolts
Thread both stainless steel bolts through the cover bolt holes and into the frame receiver sockets. Tighten to snug-plus with a standard hex driver. Do not overtorque — these are locking, not pressure-tight, fasteners.
Final Grade Check
Confirm finished cover surface is at or within ¼" of final paved or finished grade per project specification. Backfill and compact around the frame base following applicable geotechnical requirements.
Complete Your Specification
Related Manhole Frames & Covers
Explore the full Amercast manhole frame and cover range — from 4"-deep light-duty assemblies to H20-rated heavy-duty covers for highway and municipal applications.
Ready to Specify or Order?
Same-day quote response on standard configurations. Custom markings, ADA covers, and project submittals available. Serving contractors, engineers, and municipalities across the U.S.
Request a Quote — Amercast Engineering Call us directly: 516-624-8543
Email: [email protected] | 471 N. Broadway #764, Jericho, NY 11753
