Commercial Door was sold by Columbia in the 60's -- Manufacturer = Ador.
1-3/4 inch steel ball bearing roller Steel housing (side plate on each side of bearing)
Steel gear with adjustment screws
Housing dimensions: thickness, 5/8 inch; length, 2-1/4 inch; height, 1-9/16 inch.
Housing Tab Style: Unique Housing
Housing Width: 5/8-inch
Roller Diameter: 1-3/4-inch
Roller Edge Type: Concave
Roller Material: Steel
Priced each, sold eachHelpful Article:How to Replace Rollers in an Aluminum Sliding Glass Door
This product is similar to or the same as the following part numbers in these brands:
Prime-Line Products: D 1637
Strybuc Industries: 900-15001