Several machines with spiral knives have been introduced for the purpose. That made by the Vaughn Company (Peabody, Mass.) for fleshing is one of the most satisfactory for unhairing, though any other machine of a similar type, and provided with spiral knife-blades, purposely kept blunt, may be used. The Leidgen unhairing machine, shown in [Figs. 28] and [29], is one of the latest and most ingenious.[85]
[85] E. H. Munkwitz, Milwaukee.
Fig. 28.—Leidgen Unhairing Machine.
Occasionally goods are unhaired by fulling in the “stocks”; but it is very doubtful whether the saving in labour is not more than counteracted by the loss of weight caused by submitting the hide, while its gelatin is in a partially dissolved condition, to such rough usage.
The use of the wash-wheel (see [pp. 111], [118]) for the same purpose is much more satisfactory, and may be profitably employed for common goods, especially when the hair has been loosened by painting with a sulphide mixture.
After being unhaired, the hides are “fleshed” on the beam. This work, which consists in removing any small pieces of flesh and fat left by the butcher on the inner side of the skin, should be carefully and thoroughly done; but the closeness of the fleshing required is dependent on the purpose to which the hides or skins are to be applied.
Fig. 29.—Leidgen Unhairing Machine.
It is necessary not only to remove those portions of fat which are easily visible, but also to force out that contained in the loose areolar tissue. The form of knife used in England in fleshing is shown in [Fig. 30]. It differs from the one used for unhairing in being somewhat broader and heavier, and both its edges are sharp, so that where the flesh is too tight to remove by mere friction of the knife, it may be actually cut away by holding the knife almost flat on the beam, and using the convex sharp edge. The strokes in cutting must not be too broad, or, from the convexity of the beam, the substance of the hide will be cut into in the middle, or flesh will be left at the edges of the stroke. This difficulty is avoided by the flexible knife commonly used in Germany, but in other ways its work is less rapid and effective.