AJ Manufacturing
AJ Manufacturing: Quality Walk Doors: Doors are constructed of foam injected 1-3/4” galvanized panels for strength, rigidity and R12 insulating value. Doors are Pre-Hung with 4x4-1/2” fixed pin hinges in a 4-Way universal 16 ga frame. A variety of lites, panel embossments, thermal option and painted door trim are available.
AMBICO
Since 1955 AMBICO Limited has partnered with architects and engineers to manufacture standard and specialized door and frame assemblies. Custom products include recessed panel steel and oversized steel doors and frames. An extensive stock/expedited delivery program offers immediate shipment. Experienced sales and engineering personnel can tailor your project requirements to our product.
Door Components
What You Need, When You Need It. That’s the motto of Door Components, which has been delivering hollow metal and stainless steel doors and frames since 1981. We have the fastest delivery in the industry, delivering custom hollow metal doors and frames in 10 days or less and custom stock doors the same day.
Hollow Metal Manufacturer's Association 
A division of NAAMM, HMMA is an association of more than 60 manufacturers of hollow metal doors and frames. HMMA’s website features: Our acclaimed standards and guide specification documents. A directory of HMMA members nearest your project. The Hollow Metal Manual – a comprehensive guide to the industry’s standard practices and construction specifications.
Karpen Steel Custom Doors & Frames 
Quick-ship manufacturer of 12, 14, 16, & 18 gauge hollow metal doors and 12, 14 & 16 gauge hollow metal frames, temperature rise doors, wood-grained doors, dutch doors, acoustic assemblies, lead-lined doors and frames, pocket door frames, 2-piece slip frames, elevator sub-buck and shadow line frames, round top doors and frames, gothic arch frames, and more.
Metropolitan Door Industries
works with architects and general contractors to specify and supply the correct doors, frames & hardware for specific applications. Metropolitan's product line includes a full range of standard and custom engineered doors & frames for new and retrofit projects in the commercial, institutional, educational, hospitality and healthcare markets.
Steel Door Institute - (SDI )
Non-profit association that represents 11 of the largest manufacturers of hollow metal doors and frames. Membership requires an extensive manufacturing audit to ensure adherence to ANSI standards. SDI develops rigorous standards for the use of steel doors and frames in the construction industry. SDI's website provides free standards and specifications, industry alerts, and FAQs.
Stiles Custom Metal 
Specify Stiles for industrial or commercial applications. Custom doors and frames in steel or galvanized, factory primed or finish painted. Factory hardware prep and glass installation available. Fire rated UL 10C. Wide variety of elevations and configurations. 40 years experience. For immediate assistance call 209 / 538-3667
Timely Industries
Timely pre-finished steel door frames offer six in stock or 29 custom colors of durable baked-on polyester coatings. We'll also match any color. Timely frames feature "snap-lock" casings in five versatile profiles of steel, aluminum and PVC. Even wood trims supplied by others can be easily fastened to our basic steel frames without milling.
4specs Discussion Forum - Great place to ask questions about specifications, products and technical data. Free - no registration required to read or post (subject to moderation).
See also:
08 1050 - Door Accessories - (Includes louvers, vision lights and kick plates)
08 1700 - Preassembled Metal Door and Frame Units
08 1118 - Residential Steel Doors
AJ Manufacturing
AJ Manufacturing: Quality Walk Doors: Doors are constructed of foam injected 1-3/4” galvanized panels for strength, rigidity and R12 insulating value. Doors are Pre-Hung with 4x4-1/2” fixed pin hinges in a 4-Way universal 16 ga frame. A variety of lites, panel embossments, thermal option and painted door trim are available.
AMBICO
Since 1955 AMBICO Limited has partnered with architects and engineers to manufacture standard and specialized door and frame assemblies. Custom products include recessed panel steel and oversized steel doors and frames. An extensive stock/expedited delivery program offers immediate shipment. Experienced sales and engineering personnel can tailor your project requirements to our product.
Door Components
What You Need, When You Need It. That’s the motto of Door Components, which has been delivering hollow metal and stainless steel doors and frames since 1981. We have the fastest delivery in the industry, delivering custom hollow metal doors and frames in 10 days or less and custom stock doors the same day.
Karpen Steel Custom Doors & Frames
Quick-ship manufacturer of 12, 14, 16, & 18 gauge hollow metal doors and 12, 14 & 16 gauge hollow metal frames, temperature rise doors, wood-grained doors, dutch doors, acoustic assemblies, lead-lined doors and frames, pocket door frames, 2-piece slip frames, elevator sub-buck and shadow line frames, round top doors and frames, gothic arch frames, and more.
Metropolitan Door Industries
works with architects and general contractors to specify and supply the correct doors, frames & hardware for specific applications. Metropolitan's product line includes a full range of standard and custom engineered doors & frames for new and retrofit projects in the commercial, institutional, educational, hospitality and healthcare markets.
Stiles Custom Metal
Specify Stiles for industrial or commercial applications. Custom doors and frames in steel or galvanized, factory primed or finish painted. Factory hardware prep and glass installation available. Fire rated UL 10C. Wide variety of elevations and configurations. 40 years experience. For immediate assistance call 209 / 538-3667
Timely Industries
Timely pre-finished steel door frames offer six in stock or 29 custom colors of durable baked-on polyester coatings. We'll also match any color. Timely frames feature "snap-lock" casings in five versatile profiles of steel, aluminum and PVC. Even wood trims supplied by others can be easily fastened to our basic steel frames without milling.
Hollow Metal Manufacturer's Association
A division of NAAMM, HMMA is an association of more than 60 manufacturers of hollow metal doors and frames. HMMA’s website features: Our acclaimed standards and guide specification documents. A directory of HMMA members nearest your project. The Hollow Metal Manual – a comprehensive guide to the industry’s standard practices and construction specifications.
Steel Door Institute
Non-profit association that represents 11 of the largest manufacturers of hollow metal doors and frames. Membership requires an extensive manufacturing audit to ensure adherence to ANSI standards. SDI develops rigorous standards for the use of steel doors and frames in the construction industry. SDI's website provides free standards and specifications, industry alerts, and FAQs.