The 8-digit counter register is at the left of the carriage, with the 13-digit accumulator at the right. The registers are driven from the rotor by two sets of intermediate star wheels on the shaft at the top rear.

The carriage is positioned by toothed rack at its lower left-hand end, which engages with a a push-button mechanism at the front of the machine. The carriage moves 7 steps of 7mm (49mm total) in the channel at the front of the base.

The accumulator and counter registers and their clearing handles can be removed from the carriage as complete assemblies.

The cam discs on the inner ends of the register shafts connect (via an intermediate linkage) to the interlock disc at the left-hand end of the rotor. The interlock prevents a clearing operation unless the rotor is in its home position, and prevents the rotor moving while a clearing operation is in progress.

The left-hand register is variously known as the "counter" register (because it counts turns of the rotor), the "quotient" register (because that is where the quotient appears in division), or the "proof" register (which "proves" the number of turns in multiplication).

This view shows the counter register with the carriage installed in the machine. The register is secured at the outer end by a link between the top and front shafts, and at the inner end by a screwed retainer.

A single operating finger geared to the mainshaft engages with the intermediate star wheels and advances the selected digit by one position for each turn of the rotor. Note that the top of the mainshaft has had to be cut away to allow the finger to pass.

The counter wheels are numbered in both directions to avoid a complement display when the rotor is turned backwards for subtraction. Numbers 0 to 8 in one direction are in white for addition, and 1 to 9 in the other direction are in red for subtraction. Zero and 9 only appear once, so 9 is red regardless of direction. There are 18 numbers on the wheel, not 20, and 9 teeth on the star wheel to give the 2:1 reduction.

There is no carry mechanism on the counter register, as it is never necessary to make more than 9 turns in any digit position. However, a tens transmission was available on the more complex (and expensive) machines to allow various short-cut methods in multiplication and division.

Each numeral wheel on the accumulator has a single projection formed on the inside of its drive gear (between digits 3 and 4), which engages with the toothed keyway on the register shaft to perform the clearing operation. (The notch adjacent to digit 6 on the gear is a clearance slot to allow the wheels to be assembled over the keyway).

The register shaft can move a short distance horizontally. It is pre-loaded to the left by a strong spring inside the shaft bushing, and restrained by the pin which runs on the outer face of the bushing. The pin normally sits in the notch at the rear of the bushing (in the 3 o'clock position), with the shaft pressed fully to the left. The teeth on the keyway are positioned to the left inside the numeral wheels, clear of the projections on the right, so the wheels are free to rotate.

The clearing handle is pinned to the end of the register shaft. As the handle is turned forward (clockwise), the notch and ramp at the rear of the bushing will pull the register shaft outwards by about 2mm. The teeth on the keyway move to the right inside the numeral wheels, bringing them into line with the internal projections. As the handle is turned further, the keyway teeth engage with the projections and turn the wheels backwards towards zero. The mechanism disengages when the pin drops back into the slot at the end of the turn.

The clearing mechanism for the counter register is similar, except that the pin is on the inner end of the bushing and the shaft moves inwards.