Marchant Pony continued tweaks and fixes

The old, battered Marchant Pony is not yet a very good calculator, but improving.

It is looking better than it did originally - and does very stylishly have matching woodgrain handle and baseboard.

To make it still better -or at least nicer- continued tweaking and fixing of the machine. 

The pinwheel drum of the 1920 machine was also completely taken apart, all parts cleaned and re-assembled. This drum does not have a date scratched in, but a stamped number - A977.

Unknown what these codes mean. Similar numbers are found on the check-dials frame, on the carriage and on the carriage-rail, etc. These could be job or order numbers, or quite possibly employee numbers.

Anycase, the 1920 pinwheel parts were placed back into the 1920 machine, using the shaft of the 1919 pinwheel. The 1920 dials were in slightly better condition than the 1919 drum and also (surprisingly) there are several minor design-differences. The donor-machine 1919 drum worked fine, but re-fitting the 1920 dials keeps machine 70049 a little more 'original'. 

Oddly, the 1920 dials fit the 1919 shaft fine, but the 1919 dials do not fit on the 1920 shaft; not quite fitting the key. Another indication that dimensions bach then at Marchant were 'inexact' or perhaps per-batch is that the washer that goes next to the clearing-arm is matched to fit the specific drum-element, like a shim.

The washer thickness is matched to its specific drum-element - in above image shows the different thickness of the washers of the two machines. There must have been a lot of test-fitting and machining of parts to fit in the Marchant factory.

Images of other Marchant Pony calculators online suggested that the grey, thick felt that was still with one of the machines is likely original. The holes for the screws are sloppily cut out, but that may have been done later. This thick felt thus cleaned and placed under the machine instead of the new green sheet.

The donor-machine came with ill-fitting hex-bolts: M6 with an 8.8 strength-marking, they are probably items from the 1960s. The target-machine's original American-thread screws were present, but badly mangled and bent. With a lot of filing, they now do at least fit the thread in the machine base and hold it secure.

These Marchant calculators' baseboards sit on very distinctive rubber feet. These are nailed in place, using four nails per foot. The feet on the donor baseboard were rather damaged, but dimensions could be taken from the surviving parts and a quick CAD model created to make new 3D printed feet in TPU rubber.

The old feet then removed and the new feet hammered into place with similar black nails.

Now not on original feet, but the machine has a less 'gnawed' look and a proper grip again - plus rubber-parts are reasonable items to be replaced at a refurbishment.

Several Pony calculators seen online have a small paper 'notice'  pasted on the baseboard. This baseplate indeed showed signs that something had been glued to it, vague remnants/damage in the lacquer on the front-left corner: probably this specimen also originally had its Six Dont's notice.

This lists of Six Dont's for the user was recreated using images of surviving (bits) of these that can be found online.

The surviving specimens are all very brown - unclear if this is from aging, or if they were brown originally. Unsure of what would be a good color, a range of brownish hues were tried.

Pasted to the baseboard with a starch-based glue - it may yet be replaced with a darker brown. (Starch: warm water should weaken/remove the glue, i.e. reversible.)

This old, battered Marchant Pony is perhaps not a very good calculator, but a great item. It now does work, but not as smooth to operate or reliable as it once would have been. It is however a great object for tinkering and this re-building using a donor-machine too gives a lot of fascinating insights into the workings and the manufacture of these calculators, made well over a century ago.

It is a great historic technological item!