Uploaded February 2025 | Updated September 2026, 1 week ago
Patented in 1921 by Russell Hook of Grand Rapids, Michigan, the Lightning Calculator/Adding Machine was manufactured for more than 40 years and was one of the most popular and successful dial adders of the mid-20th century. Its development and corporate history, however, are extremely convoluted and emblematic of that of many commercial products of its type.
0:00 Introduction
1:05 Corporate/Development History
5:20 External Features
6:37 Operation: Addition
6:58 Operation: Subtraction
7:58 Clearing Bar
8:06 Calculator Co. Readout
8:45 Later Versions
9:34 Disassembly and Mechanism
11:06 Manufacturing Precision & Adding Machines
14:10 Outro
SOURCES
americanstationer.wordpress.com/2017/04/23/lightning-adding-machine
https://americanhistory.si.edu/collections/object/nmah_690296
jaapsch.net/mechcalc/lightning.htm
patents.google.com/patent/US845747
patents.google.com/patent/US908731
patents.google.com/patent/US1574249
Patented in 1921 by Russell Hook of Grand Rapids, Michigan, the Lightning Calculator/Adding Machine was manufactured for more than 40 years and was one of the most popular and successful dial adders of the mid-20th century. Its development and corporate history, however, are extremely convoluted and emblematic of that of many commercial products of its type.
0:00 Introduction
1:05 Corporate/Development History
5:20 External Features
6:37 Operation: Addition
6:58 Operation: Subtraction
7:58 Clearing Bar
8:06 Calculator Co. Readout
8:45 Later Versions
9:34 Disassembly and Mechanism
11:06 Manufacturing Precision & Adding Machines
14:10 Outro
SOURCES
americanstationer.wordpress.com/2017/04/23/lightning-adding-machine
https://americanhistory.si.edu/collections/object/nmah_690296
jaapsch.net/mechcalc/lightning.htm
patents.google.com/patent/US845747
patents.google.com/patent/US908731
patents.google.com/patent/US1574249
