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Friden DW-8


Friden DW-8

This Friden DW-8 was made in the early 1950’s. This is an eight column calculator with automatic division and division tabulation. This machine does not have the secondary multiplier keyboard like the Friden STW or SBT models, so multiplication is done manually on this machine. ( I do have a STW waiting to be repaired though :) ) This calculator is the successor to the Friden D-8, but now with the modern button and outer panel style. The previous darker style with chrome accents was switched to a more minimalist design in 1949.

Friden DW-8 Right Side

Friden DW-8 Back

Friden DW-8 Left

I acquired this calculator for a mere fifteen dollars in Ohio. A piece of tape on the machine shows it had been sold for a bit more at one time or another and states that it’s “a steal”.

Friden DW-8 Tape


Friden DW-8 Register

This Friden DW-8 has a nine column counter and a seventeen column accumulator register. Both registers have clearing lever on the right side. Each clearing lever can be rotaded up to disable automatic clearing of the register by the machine or the Clear Carriage button. Both registers have slide-able decimal markers.


Friden DW-8 Controls

To the right of the keyboard, starting at the top is the Keyboard Lock lever, Div Stop lever, and Add lever. The Keyboard lock lever prevents the keyboard from being cleared. The Div Stop button is used to stop the machine in division or other operations. It can be pushed up to stop the machine as soon as possible or pulled down to stop the division after the next digit is found. And the add button is used to enable or disable keyboard clearing after each operation.

Below that is the Enter Dividend button. This button clears the registers, moves the carriage all the way to the right, and places the number on the keyboard into the accumulator. Below that are the buttons for shifting the carriage right and left.

To the right of those buttons are the subtract and add button. Below that are the two division buttons. Why two? If both are pressed, the counter is incremented. If just the left one is pressed, the counter is decremented.

Below that are the keyboard clearing and carriage clearing buttons. Below the keyboard are movable decimal markers. Further down is a arrow that slides to reset all of the keyboard decimal markers. And finally, to the left of the keyboard is the counter control switch. This switch reverses the direction of the counter register.

Friden DW-8 Keyboard


This machine was a bit of a pain to repair. These Friden calculators have a much simpler internal operating principle than say, a Marchant machine. Marchant machines rely on a more complicated proportional gear system to perform calculations while Friden uses the simpler stepped drum mechanism. However, Friden calculators seem to have a lot more moving levers and arms that like to seize up, become misaligned, or move out of place. Most of the trouble was from arms and linkages being seized, having to find them, and oiling them.

The carriage shifter had also gotten out of time. This required removing the carriage, readjusting the black gear to where the point is vertical, and adjusting the arms around it.

Friden DW-8 Shifter

Another issue presented itself after I put the covers back on the machine. Division suddenly jammed the machine up. It took a while, but I eventually tracked it down to this part:

Friden DW-8 Break

The gear on the right slides in and out to engage with the left gear during division. Somehow, the ring behind this right gear with the pin on it had come loose and was freely rotating. This cause the gear to engage or disengage at the wrong points in the division cycles and jammed up the machine. It took some work, but I figured out the correct position the pin should be in and used epoxy to keep it from moving again. The picture shows the ring, pin, and gear in the correct home position.

Internal Pictures

Note: These were taken with a blot placed in a gear on the right side of the machine used to turn the machine over by hand, this is removed before the covers go on.

Friden DW-8 Internals

Friden DW-8 Internals

Friden DW-8 Internals

Friden DW-8 Internals

Friden DW-8 Internals

Friden DW-8 Internals

Friden DW-8 Internals

Friden DW-8 Internals

Friden DW-8 Internals


Here’s a video of the machine performing division with the outer panels removed:

And a video of the machine performing division in slow motion!

This post is licensed under CC BY 4.0 by the author.