Vintage Underwood 10-Key Mechanical Adding Machine
Vintage Office Equipment & Calculators

Vintage Underwood 10-Key Mechanical Adding Machine

This is a mid-20th-century manual adding machine manufactured by Underwood. The device features a heavy-duty cast metal housing with a classic grey crinkle-finish or matte industrial paint. It is a '10-key' style mechanical calculator, a significant design evolution from earlier full-keyboard models. The machine is equipped with a numerical keypad (1-9 with a large 0/clear key at the bottom) and several functional keys in contrasting orange and black. It includes a mechanical paper carriage at the top for printing results onto a paper roll, though no roll is currently installed. A manual crank handle is visible on the right side, used to cycle the internal gears and perform calculations. Centrally located on the front face is the iconic silver and white Underwood logo featuring a winged crest. The condition appears fair to poor; it is covered in a significant layer of dust and grime, suggesting it has been in unventilated storage for decades. The metal shows signs of surface oxidation and the keys appear somewhat worn. There is a handwritten price tag adhered to the front housing. Craftsmanship is typical of the post-WWII American office equipment era, prioritizing durability and weight to prevent sliding during heavy use.

Estimated Value

$45-85

Basic Information

Category

Vintage Office Equipment & Calculators

Appraised On

February 23, 2026

Estimated Value

$45-85

Item Description

This is a mid-20th-century manual adding machine manufactured by Underwood. The device features a heavy-duty cast metal housing with a classic grey crinkle-finish or matte industrial paint. It is a '10-key' style mechanical calculator, a significant design evolution from earlier full-keyboard models. The machine is equipped with a numerical keypad (1-9 with a large 0/clear key at the bottom) and several functional keys in contrasting orange and black. It includes a mechanical paper carriage at the top for printing results onto a paper roll, though no roll is currently installed. A manual crank handle is visible on the right side, used to cycle the internal gears and perform calculations. Centrally located on the front face is the iconic silver and white Underwood logo featuring a winged crest. The condition appears fair to poor; it is covered in a significant layer of dust and grime, suggesting it has been in unventilated storage for decades. The metal shows signs of surface oxidation and the keys appear somewhat worn. There is a handwritten price tag adhered to the front housing. Craftsmanship is typical of the post-WWII American office equipment era, prioritizing durability and weight to prevent sliding during heavy use.

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