The scudding machine figured (Fig. 6) was invented by Sir John Turney in 1880,[17] and is the only type of machine which will safely scud split skins. It will readily be understood that the usual type of scudding machine, in which a spiral knife is used, would tear the delicate structure of the grain. The Turney scudding machine works with hard, circular brushes, which revolve against a wooden roller carrying the skin. At the same time a continuous stream of water, at a temperature of 110° F., is sprayed upon the skins from a perforated pipe.
[17] The original Turney scudding machine, was invented in 1871, and patented in that year. The specifications are numbered 1351, and 3310, 1871. It was also patented in America. Specification No. 131,480, dated September 17, 1872. Improvements in apparatus for cleaning and scouring hides and skins.
After scudding, the skins are washed in cold water for about ten minutes. This checks the action of the puer, and also washes away any loose dirt. They are then ready to pass on to the drench (Chapter IX.), or to the pickling process, or direct to the tan liquor, according to the kind of leather required.
*The Bating of Hides for Harness or Dressing Purposes.*--The hides intended for harness leather, or for dressing purposes, are usually bated with hen or pigeon manure. The exact process varies in different tanyards, being dependent upon the condition of the pelt prior to bating, as to whether it is bated directly after fleshing or receives a preliminary deliming. The process is also dependent upon the amount of bating action required for the specific purpose prior to tanning, but the following three methods are in actual use, and may be taken as typical methods:--
_Harness Backs._--About a hundredweight of hen manure is put into a suitable tub or vat capable of holding about fifty gallons; some thirty gallons of water, at a temperature of about 100° F., is poured on to the manure, and the whole is thoroughly stirred up by means of a wooden stick or plunger, working the manure about in order to mix it to a consistence of thin soup. The vat is now stored in a warm place, so that the temperature is kept about 70° F.--it is customary to store this in the boiler-house, or some similar warm room. It should be stirred two or three times a day, until it begins to show signs of working; two days is generally sufficient for this.