What Steward Machine does

Steward Machine Co., Inc. is a 120-year-old, privately held, family-owned heavy industrial manufacturer headquartered in Birmingham, Alabama. Founded in 1904 to supply the coal and iron ore mining industry in central Alabama, the company has expanded its scope over time to serve four primary verticals: movable bridges, hydropower, lock and dam infrastructure, and aerospace. The company describes itself as the largest manufacturer of movable bridge machinery in the world, with a track record of 27 vertical lift bridges, 19 bascule bridges, and 22 swing bridges.

Steward operates three plant locations totaling more than 290,000 square feet of manufacturing space, anchored by 500-ton crane capacity and very large CNC turning and milling equipment (turning lathes up to 240" diameter, horizontal mills up to 714", gantry mills up to 420"). Capabilities run from CNC precision machining and metal fabrication through welding, heat/stress relief, gear cutting, AISC-certified structural steel fabrication, assembly, coatings, and shipping. The Bainbridge, Georgia facility provides direct barge launch-way access to the Gulf Intracoastal Waterway for oversized components. The company also owns the Earle Gear brand — acquired in 1986 from Philadelphia-based Earle Gear and Machine Co. — which supplies patented Earle speed reducers, Cushionlok bridge lock systems (in service since 1995), lock bar operators, and pillow blocks to movable bridge operators worldwide. AISC certifications at the highest level (Advanced Major, Hydraulic Steel Structures, Fracture Critical Endorsement, Sophisticated Paint Endorsement) gate access to public infrastructure bids.

The company generates revenue primarily through project-based, custom one-off contracts — large fabricated and machined assemblies such as 240-ton miter gates for the U.S. Army Corps of Engineers, 17-foot counterweight sheaves for state DOTs, wicket gate refurbishments for utilities, and 55-foot Tangential Towers for NASA's SLS program. Customers are almost exclusively government agencies (USACE, state DOTs, NASA) and regulated utilities (Consumers Energy, Georgia Power). Pricing is bespoke per project, with no published price list, and there are no disclosed recurring SaaS, subscription, or licensing revenue streams; the proprietary Earle Gear product line functions effectively as specialty hardware sales into the same installed-base customer set. The company remains entirely founder/family-owned with no venture capital, private equity, or public shareholders.

Name

Steward Machine

Legal name

Steward Machine Co., Inc.

Website

https://stewardmachine.com

Company type

Private

Founded year

1904

Operating status

Operating

Headcount range

101–250 employees

Short description

Steward Machine is a 120-year-old, family-owned Birmingham, Alabama heavy industrial manufacturer that fabricates custom, large-scale steel components and proprietary bridge machinery for movable bridges, hydropower, lock and dam, and aerospace projects, primarily serving U.S. government agencies and regulated utilities.

Ownership category

akta.pro rank

Product category

Heavy Industrial Manufacturing / Movable Bridge Machinery

NAICS

Overhead Traveling Crane, Hoist, and Monorail System Manufacturing (333923), Speed Changer, Industrial High-Speed Drive, and Gear Manufacturing (333612), Construction Machinery Manufacturing (333120)

SIC

Construction Machinery & Equip (3531), Special Industry Machinery (No Metalworking Machinery) (3550)

akta.pro primary industry

Crane & Hoist Components (Wire Rope, Chain, Drums, Sheaves, Motors, Controls) (IMAHAJAK)

akta.pro secondary industries

Crane & Hoist Safety & Monitoring Systems (Limiters, Anti-collision, Load Monitoring) (IMAHAJAL), Overhead (Bridge) Cranes (IMAHAJAC)

Keywords

• Heavy industrial fabrication
• Movable bridge machinery
• Structural steel manufacturing
• Hydropower turbine components
• Custom CNC machining

Headquarters

HQ city

Birmingham

HQ country

United States

HQ region

North America

Offices3 records

Markets served

GTM type

B2B

Offering type

Hardware or Manufacturing

Cost components

Personnel, Operations, Infrastructure, Technology or R&D, Supply Chain

Revenue model

1. Custom Heavy Manufacturing Services: Project-based custom manufacturing, fabrication, and machining services for large-scale infrastructure components including movable bridges, hydropower equipment, lock and dam structures, and aerospace components. Revenue is generated through one-time project contracts with government agencies, engineering firms, and industrial clients requiring bespoke heavy machinery and structural components.
2. Proprietary Gear Products (Earle Gear): Manufacturing and sale of Earle Gear branded speed reducers, Cushionlok bridge locks, lock bar operators, and pillow blocks. These proprietary products are sold as replacement components and new installations for movable bridge systems.

Go-to-market motion1 record

Distribution channels1 record

Marketing channels4 records

Core offering

Steward Machine is a heavy industrial manufacturer that fabricates, machines, stress-relieves, welds, gear-cuts, and assembles large-scale infrastructure components for movable bridges, hydropower facilities, lock and dam structures, and aerospace projects. The company delivers complete turnkey mechanical and structural packages from shop drawings through final assembly, and manufactures the proprietary Earle® Gear product line of bridge lock systems, speed reducers, lock bar operators, and pillow blocks acquired in 1986.

Product overview

Steward Machine is a heavy industrial manufacturing company offering turnkey fabrication, machining, and assembly services primarily serving the movable bridge, hydropower, lock and dam, and aerospace industries. The company's branded product portfolio centers on Earle® Gear products (speed reducers, lock bar operators, Cushionloks®, and pillow blocks), which Steward Machine acquired in 1986 and continues to manufacture. Services include CNC precision machining, metal fabrication and welding, AISC-certified structural steel fabrication, engineering, project management, quality control, assembly, coatings, and shipping—all provided across three manufacturing facilities totaling over 290,000 square feet.

Differentiator

Problem solved

Functional benefit

Brands

• Earle Gear: Earle Gear Speed Reducers, Lock Bar Operators, Cushionloks, Pillow Blocks, and Reducers specially designed for low-speed, high-torque applications in movable bridges, heavy lifting, and hoisting machinery. Earle pioneered the development and use of Differential Speed Reducers in movable bridge operating machinery systems.

Products and services

• Earle® Speed Reducers Specially designed low-speed, high-torque speed reducers for movable bridge operating machinery, heavy lifting, and hoisting applications; features a balanced three-pinion bevel gear assembly ensuring load sharing between two output shafts, compact self-contained fully enclosed units with automatic lubrication and American Gear Manufacturers Association compliance.
• Earle® Cushionloks® Bridge Lock System Patented rectangular bar bridge lock system that fits through a guide on one leaf tip and into a receiver on the other to enable shear load transfer between bridge leaves; features stiff disc springs supporting wear shoes and eliminates uncontrolled bounce of leaf tips during vehicular traffic passage; lock bar sizes range from 4 x 6 inches to 7 x 10 inches supporting 25,000 to 120,000 lbs of shear load transfer per lock bar.
• Earle® Lock Bar Operators (EG-2B, EG-3, EG-4, EG-4XL) Weatherproof, self-contained linear actuators using an Acme lead screw and driven captive nut to move lock bars and other heavy-duty connectors between bridge structures; available in EG-2B, EG-3, and EG-4/EG-4XL models with strokes up to 28 inches for bascule, vertical lift, and swing bridges as well as gate lock applications.
• Earle® Pillow Blocks Two-piece split steel housing pillow blocks with ASTM B-22 bronze bushings for bridge and industrial machinery applications; rated per AASHTO and AREMA load specifications with two-way thrust capacity and double spiral lubrication grooves.

Quantifiable outcome

• Delivered 10 bridge bogeys weighing 40-60 tons each ahead of schedule for Miller Park Retractable Roof
• +3 more outcomes

Named customers12 records

Segments4 records

Ideal customer profiles3 records

Technology focussed No

API detail

Has API

No

API docs

API detail

Core technology

AI maturity

App detail

Feature4 records

Partnerships

One partnership is on record.

• Earle Gear and Machine Co. (Acquired Assets)coreOEM/ Whitelabel/ Licensing Partner · 1 January 1986In 1986, Steward Machine acquired the assets of Earle Gear and Machine Co., Philadelphia, Pennsylvania. Steward Machine now manufactures the same reliable Earle Gear Speed Reducers and Lock Bar Operators utilizing Earle concepts and engineering data. This acquisition supplemented Steward Machine's existing gear manufacturing capabilities and made available patented Cushionlok bridge locks, pillow blocks, lock bars, and reducers to customers.

Scale indicators8 records

Recent moves6 records

Expansion highlights5 records

Market position

Competitive moat5 records

Key risks5 records

Key highlights7 records

Customer concentration

• Facebookfacebook.com/stewardmachine
• LinkedInlinkedin.com/company/steward-machine-co/?viewAsMember=true

Compliance3 records

Revenue estimate

Valuation estimate

Number of profiles

Profiles1 record

Subsidiaries1 record

Funding overview

Funding rounds

Investors

Funding detail is available on the Subscription and Enterprise plan.Contact sales →

M&A

Investments

M&A and investment is available on the Subscription and Enterprise plan.Contact sales →

Frequently asked questions about Steward Machine