Bark mill

Bark mills, also known as Catskill's mills, are water, steam, horse, ox or wind-powered edge mills[1] used to process the bark, roots, and branches of various tree species into a fine powder known as tanbark, used for tanning leather.

This powdering allowed the tannin to be extracted more efficiently from its woody source material.

[2] A barker would strip the bark from trees so that it might be ground in such mills,[3] and the dried bark was often stored in bark houses.

[citation needed] Various machinery was used to chop, grind, riddle and pound the bark.

These included Farcot’s bark-cutting machine (used extensively in France), Weldon’s bark-grinding mill, and a device known as a Wiltze's mill or Catskill's mill (prevalent in 19th-century America).