The Millionaire Calculator

by Jim McDermaid


The Millionaire Calculator is a very different and interesting machine

The machine is very heavy. An engine turned steel main frame and a ton of machined brass gears. The carriage (and accumulator was to the front of the machine. A small engraved wheel for each of sixteen places of result was viewed through a beveled hole in the top plate of the carriage and each result wheel could be turned with a small knob . There is a small nickel plated Baton shaped pin that fits a hole between each number to mark decimal place. The larger ball shaped knob at the right of the carriage cleared the accumulator and the larger knob on the left allowed you to unlatch and move the carriage. To the right of the carriage latch knob at the top left of the carriage is an 8 place operation counter and clear knob.

The crank at the upper left selected the multiplier number (shown in the 1 position).

The sliders in the middle permitted entering a number.

The small knob to the top right selected the math mode, multiplication, division, subtraction and addition.

The crank on the right was turned 360 degrees clockwise and performed one operation.

For addition you would select the addition mode and put the multiplier handle in (1). With each turn of the crank you would add the numbers entered in the sliders and the carriage would not shift.

Division was done by selecting division, manually entering the number in the result register, entering the divisor in the slides and then using the scale located in the lid you would estimate the number to set the multiplier handle to and give it a crank. There was a bell that sounded if you overflowed the accumulator.

The stepped drum performs the ten’s carry The drum and accumulator all moved on a set of rollers. This is a fairly complicated mechanism and had a lot of moving parts.

The multiplication use a mechanical look-up table. The table is a rack of different length brass pins. Turning the multiplier handle raised the table so a different row of pins engaged the rack gears. Each rack gear engaged a small cog that could be shifted on a square shaft by a brass fork attached to the slider. The square shaft engaged a gear in the accumulator / carriage. The internal gears were also engraved with numbers so you could read the position of a gear from inside the machine.

Every part in this calculator was machined and it was built like a fine clock.

Attached to the lid (right side of label) were two small shipping screws. A knurled brass head with a machined steel shaft. These were to be put in when moving the machine to lock down the heavy carriage and Multiplier table mechanism.

The finish was blued brass plates with all engraving inlayed with silver. The case was aluminum panels that could be removed for service. The top was tin (about as thin as a pop can) painted black enamel The white, metal screened instruction plate with the division estimator was riveted to the lid.

The Millionaire machine is laid out in a simple straight forward arrangement. All of the parts are machined either out of brass or fine polished machined steel. Everything is nicely assembled with machine screws. The top of the machine and all partially hidden panels are a blued brass. The engraving is all plated or inlayed with silver plate. Each system is all together in one location. If you were to look straight down on the top of the machine at the TOP LEFT is the multiplier lever. You lift the knob and turn the lever down for a higher number 0 through 9. The mechanical lookup table assembly is located directly below the lever. TOP CENTER is the location of the input slider assembly and associated rack gears directly beneath it. TOP RIGHT is the selector for the math mode. You lift the knob and turn the selector to show through the window the mode you want Subtraction, Division Multiplication, and Addition. FAR RIGHT is the operation crank. To perform an operation, you lift the knob and turn the crank one turn clockwise. To multiply say 312 X 98, you would enter 312 on the sliders set the multiplier lever to 9, position the carriage to the right, turn the operation crank one turn. move the multiplier to 8 and turn the operation crank one turn. With two turns of the crank you have the answer 30576 shown in the result wheels in the carriage as well as the multiplier value 98. To do the same on a Curta would take 17 crank turns. Division is slower because you must do an estimation and enter a number on the multiplier lever. Square root can be done but I can go much faster on a Curta.

Jim McDermaid

[ Internal Views ]

Gosh, if you've ever compared a tower clock movement to that of a grandfather clock, the Millionaire is surely the counterpart of the tower clock, it seems to me!

My video/browser combination (browser is offline only) probably didn't do justice to the images, but I'm reasonably sure I saw the Friden/Curta-like selection forks sticking up in the air. I could take a guess at some of the parts of the machine, and be fairly sure that I was describing things right..

At first, I was really surprised that every position of the selection gears engaged a full rack; it wasn't until the last image that I realized that apparently the Millionaire always uses its mechanical mult. table (the array of brown rods of various lengths) even for adding and subtracting! A conventional add cycle must have been quite close to multiplying by one.

Iirc, the Bollée (sp?) machine used holes drilled to various depths to serve as the mechanical mult. table. Then, of course, there was the Moon-Hopkins billing machine, which also used a mechanical mult. table.

However, I'm at sea when it comes to more-basic stuff such as where the accumulator is.

Nicholas Bodley

X-Number World