Convert from catty [Japan, Thailand] to fother [lead]

Unit Definition (catty [Japan, Thailand])
The catty [Japan, Thailand] is a weight unit of the colonial period in East and Southeast Asia, originating as the kati in Malaya. The catty varied a little from market to market. Typically it was equal to about 4/3 pound avoirdupois (604.79 grams), and it is still equal to that weight in Malaysia. In Thailand, the catty is used now as a metric unit equal to exactly 600 grams (1.3228 pounds).

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.