The external appearance of the classic Burroughs adding machine changed very little from 1892 into the 1920s. The distinguishing features are the high sloping keyboard, the bevelled glass front, and the printing mechanism out-of-sight at the rear of the machine. The glass front was a necessity, as the display register is actually inside the casing. Many machines had glass sides as well, to display the internal mechanism and the ornate cast-iron framework.

The illustration shows a manually-operated glass-sided machine for Sterling currency (with Farthings). The paper carriage takes rolls, sheets, or printed forms, and has an end-of-page indicator and bell. The carriage can be positioned manually to adjustable stops.

The machine performs addition only, with no provision for subtraction either directly or by addition of complements. There are two large keys on the left-hand side for totals and sub-totals, and three smaller keys for non-add, repeat, and error (or keyboard clear). The red buttons at the top of the machine act as zero keys to clear the individual keyboard columns.

A Model 2 adding machine from around 1919. The machine has 9 columns for Sterling currency (without Farthings), and is fitted with a wide paper carriage and an electric motor drive. The machine is supported on a tubular steel frame with the motor and gearbox mounted underneath. The pillars on the left-hand side of the frame supported a writing table which is no longer present. The frame is fitted with four retractable castors to allow the 120-pound assembly to be moved with safety.

The Burroughs Class 3 machine is based on the mechanism designed by William H Pike Jr for the Pike Adding Machine Company. Pike appears to have worked previously for William Burroughs in St Louis, as his name appears as inventor on American Arithmometer patents from 1897. Pike left St Louis around 1901 and established his Pike Adding Machine Company in Orange, New Jersey. Production commenced in 1904, and was well established when the company was acquired by Burroughs in 1909. When Burroughs relocated the manufacturing operation to Detroit, the Pike factory in Orange was acquired by the newly-formed Monroe company.

The Pike machine was smaller, simpler, and cheaper than the Burroughs, but its biggest advantage was visible printing. The printed results were in full view of the operator, rather than hidden at the back of the machine. Burroughs continued to develop the machine into the 1920s, adding features such as two-colour and split printing, wide paper carriages, direct subtraction, and electric motor drive. The machine was sometimes known as the "flat-bed" after the long horizontal arrangement of the keyboard and the display register.

The example illustrated is a basic 7-column add-only machine for Sterling currency, with a fixed paper-roll printing mechanism.

A very early 9-column Burroughs Calculator for Sterling currency, in a black pressed-metal case.

Although the case shows a remarkable similarity to the Felt & Tarrant Comptometer, the Burroughs keyboard differs in a number of areas. The ten-shillings column has a full row of "1" keys, while the 10 and 11 pence keys are shifted sideways into the farthings column. There is no key release button, as the machine does not have the mis-operation locking mechanism. There are no subtraction cutoff levers, so it is necessary for the operator to left-fill a complement entry with 9s. A small un-labelled key in the top left corner enters a 9 into the leftmost column.

This 13-column Burroughs Calculator was originally from the Post Office in Antwerp, a once-prosperous wheat-farming town in western Victoria. The Post Office (and most of the town) no longer exists. The green paint and the transfer on the front are from "Macdougalls Pty Ltd", a major firm of stationers in the Australian capital cities.

In spite of the differences in the keyboard and the internal mechanism, the obvious external similarity between the original Burroughs Calculator and the Comptometer inevitably led to litigation over patent infringements. After some adverse findings, the Burroughs machine was re-designed to become the Class 5 Calculator. The keyboard mechanism is about 3" shorter than previously, although the register mechanism is largely unchanged. The machine is housed in a rather elegant die-cast alloy casing. The legs at the rear raise the keyboard to an angle of about 15° and give the machine its distinctive "high-heeled" appearance.

A later Burroughs Calculator for Sterling currency, in a more rounded pressed-metal housing. The mechanism is raised internally to bring the keyboard to a 20° angle.

When Australia changed from Sterling to decimal currency in 1966, this 13-column machine was "converted" very easily. The shillings and pence columns were simply ignored, and the keytops on the nine decimal columns were re-arranged into colour groupings for dollars and cents. (Compare this machine to the normal Sterling keyboard on the model below). The converted machine continued in service for another ten years.

When key-driven machines were finally retired in favour of electronic data processing systems in the 1970s, many of the young girls who had trained as operators in the 1940s and 50s found themselves and their machines "surplus to requirements". This well-used and well-kept machine was presented to its operator as a souvenir on her retirement. She was obviously quite attached to her former career, as she kept the machine with its dust cover, conversion tables, and her original training notebook for a further 20 years, only parting with them when moving house after her husband's death in 1999.

A 13-column Burroughs Calculator for Sterling currency, with an internal electric motor drive. Apart from the colour scheme, the case of this British-made machine is much the same as the manually-operated model above. The motor provides the energy to operate the mechanism, in a similar fashion to an electric typewriter, giving a very light touch to the keyboard and finally eliminating the risk of partial keystrokes. The drive mechanism was designed by Walter Pasinski in 1928, and received US Patent 1901794 in 1933.

This machine is fitted with subtraction cut-off buttons (in front of the rows of keys), and a clearing key that is marked (incorrectly) with a "+" sign. Otherwise, the operation is essentially the same as the manual models.

A late-model Burroughs Calculator with an electric motor drive and a grand-total register at the rear. The machine has a pressed-metal base and a die-cast alloy cover.

The mechanism to drive the rear-mounted register was designed by Walter Pasinski in 1933 (US Patents 2240797/8). Rather than advancing both registers together, the machine accumulates a result on the front register alone. When this calculation is complete, the operator presses the Plus or Minus keys on the right-hand side to transfer the result either positively or negatively to the rear register.

An eight-column Burroughs Portable from the 1930s, with direct subtraction and an internal electric motor drive. A small cover plate on the right-hand side can be opened to install a manual operating lever when required. The function keys in the rightmost column are Sub-Total, Total, Non-Add, Repeat, and Error (or keyboard clear), with the Add and Subtract bars at the far right. This machine operates in Sterling currency, without Farthings.

A ten-column Burroughs Portable from the 1930s, with direct subtraction, electric motor drive, and a wide paper carriage. The carriage has settable tab stops, and can be used with rolls, sheets, or printed forms.

The Sterling keyboard has an unusual arrangement in order to accommodate 10 columns in the same body as the 8-column machine above. The 10 and 11 pence keys are at the top of the shillings column, and the 8 and 9 shillings are at the top of the ten-shillings column to the left.

A manually-operated Burroughs Portable from the 1950s, for Sterling currency (without farthings). The keyboard has the more conventional layout with a full row of "1" keys in the ten-shilling column, and the 10 and 11 pence keys shifted sideways into the right-most column. The function keys are the same as on the 1930s models above. The printing mechanism accommodates paper rolls up to 4" wide, and has a small "back-rest" to facilitate manual annotations on the tape.

The "J" series of ten-key adding and listing machines was first introduced in 1954.

The J524 illustrated is a basic machine with add, subtract, total, and sub-total keys on the right of the keyboard. On the left is an "Error" or keyboard clearing key, a non-add key, and a "repeat" key marked with an X for use in multiplication.

The mechanism is based on a conventional pin carriage and sliding racks, and is powered by a universal (brush-type) motor. This machine was manufactured by the Burroughs factory in France.

The J624 is similar to the machine above, with the addition of a second repeat key to enable repeated subtraction.

The J700 is generally similar to the J624, but incorporates a semi-automatic multiplier mechanism. The operator selects positive or negative multiplication on the repeat keys (now labelled R and R-), and then presses one of the red multiplier keys to perform the required number of additions or subtractions. When all digits have been processed a total is taken to print the result.

The mechanism is similar to the previous model, but with the casing an inch wider to accommodate the additional keys on the left-hand side.

This "1000 Series" J1624 is a later version of the J624 (above), in a larger and more angular case. This machine was built by the Burroughs factory in Brasil.