Convert from fother [lead] to chalder, chaldron

Unit Definition (fother [lead])
The fother is a traditional English unit of weight for lead. The fother, equal to 30 fotmals, was always a little smaller than a (long) ton. The original version seems to have been equivalent to 2160 avoirdupois pounds, and the version still being used in the nineteenth century was equal to 19.5 hundredweight or 2184 pounds.

Unit Definition (chalder, chaldron)
The chalder, chaldron is a traditional British unit of volume or weight used for dry commodities such as coal or lime. As a volume measure, the chaldron is equal to 36 bushels, or 288 British Imperial gallons; this is equivalent to 46.237 cubic feet or 1.3091 cubic meters. As a measure for coal, the chalder equals 1/8 keel or 53 hundredweight (5936 pounds or 2692.52 kilograms). The words "chalder," "chaldron," and "cauldron" are English spellings of the same old French word, which originally meant a large kettle.