1. Four iron crolle starts with four 'irons,' 'stripes,' 'bands,' 'rods,' 'ribbons,' 'baguettes, or 'blades' and is made up of some combination of alternating layers of iron and steel.
2. The 'iron' used for a Twist barrel had no more than 50:50 iron/steel and was
not twisted prior to being 'twisted' (wrapped) aroung the mandrel
From the
Journal of The Federation of Insurance Institutes of Great Britain and Ireland, 1904 "Gun and Small-Arms Factories" by A.E. Patrick, p. 149-175 From 'Gun Barrels' starting on p. 159
"Plain twist or scelp barrels are made from plain straight rods or ribands. It is the twist in the rods that cause the figure to appear in the barrels and all iron so twisted is called "Damascus"...
3. There are several descriptions of Laminated steel at the beginning of the 'British Laminated Steel' album
http://www.picturetrail.com/gallery/view?p=999&gid=18063717Short version for my pea brain: Twist and Laminated steel both start with the mixture of iron and steel fused together in a
'bloom' which is then rolled/hammered into rods.
The rods for damascus are NOT fused together but are individual strips of iron and individual strips of steel. Laminated steel rods are twisted much less than damascus, but may still have a 'crolle' pattern and are then called 'Laminated Damascus'
And laminated steel has a much higher ratio of steel to iron-usually 3-4:1
They may also have a linear pattern, but it is much less complex than 'Herring-bone' damascus.
Laminated usually has a very random black/white - iron/steel variegated pattern
The best description of the production of Twist, Damascus, and Laminated steel I've found follows:
Engines Of War: or, Historical and Experimental Observations on Ancient And Modern Warlike Machines And Implements, Including the Manufacture of Guns, Gunpowder, and Swords with remarks on Bronze, Iron, Steel, &c. Henry Wilkinson, M.R.A.S. London 1841
p. 70 Part III 'On The Manufacture of Fire-Arms, And Modern Improvements'
http://books.google.com/books?id=0XJeF_o...w3u60I#PPA70,M1 Starting on p. 87 Forging of Gun-Barrels A description of Stub, Stub-Twist, Wire-Twist, Damascus-twist, Stub-Damascus, Charcoal iron, Threepenny skelp iron, Two penny or Wednesbury skelp, and Sham-damn skelp.
The most approved modern method of converting…(horse-shoe nails)…into (
Stub-Twist) gun-barrels after carefully sorting and picking the, to see that no cast-iron or impurities are mixed with them, is first to put about half a hundred weight into a large cast-iron drum or cylinder, crossed internally with iron bars, through the centre of which a shaft passes, which is connected by a strap with a steam-engine, and the revolution of the drum actually polishes the nails by their friction against each other; they are then sifted, by which every particle of dust is removed. The steel intended to be mixed with them is clipped by means of large shears, worked by the engine into small pieces, corresponding in size to the stubs, and afterwards cleansed by a similar process. About 40 lbs. are thrown on to the inclined hearth of an air-furnace, where they are
puddled or mixed together with a long iron rod, and withdrawn in a mass called a
bloom, almost in a state of fusion, to be welded under hammer of three tons weight, by which it is formed into a long square block: this being put in, at another door of the same air-furnace, is raised to a bright red heat, and drawn out under a tilt hammer of a ton and half weight, into bars of proper size to pass the rollers, by means of which it is reduced to rods of the required size.
p. 95 Possibly a description of what was later termed
Laminated Steel For the finest description of (Stub-Twist) barrels, a certain proportion of scrap steel, such as broken coach-springs, is cut into pieces and mixed with the iron by the operation called
puddling, by which the steel loses a considerable portion of its carbon, and becomes converted to mild steel, uniting readily with the iron, and
greatly increasing the variegation and beauty of the twist. In whatever manner the iron may be prepared, the operation of drawing it out into ribands for twisting is the same. This is effected by passing the bars, while red hot, between rollers until extended several yards in length, about half an inch wide, and varying in thickness according to whichever part of the barrel it may be intended to form: these ribands are cut into convenient lengths, each being sufficient to form one-third of a barrel: one of these pieces is made red hot and twisted into a spiral form, by placing on end in the prong of an iron rod, which passes through a frame, and is turned by a handle, the riband being prevented from going round without twisting by means of an iron bar placed parallel to the revolving rod. The spiral thus formed is raised to a welding heat, and dropped on to a cylindrical rod, which being struck forcibly on the ground (called jumping) the edges of the spiral unite, and the welding is then completed by hammering on the anvil. The other spirals are added according to the length of the barrel, and the forging is finished by hammering regularly all over. The ends of the spirals should be turned up and united at each junction of spirals, to avoid the confusion in the twist occasioned by merely dropping one spiral on anther; but this is rarely done. Wire-Twist, of any degree of fineness, may be obtained by welding alternate laminae of iron and steel, or iron of two qualities, together; the compound bar thus formed is drawn into ribands, and twisted in the same manner as the preceding.
p. 96 The iron called
Damascus, from it’s resemblance to the celebrated Oriental barrels and swordblades, is now manufactured in great perfection in this country, as well as in France and Germany, and may be varied in fineness or pattern to almost any extent, according to the various manipulations it may undergo. One method is to unite, by welding 25 bars of iron and mild steel alternately, each about 2 feet long, 2 inches wide, and ¼ of an inch thick; and having drawn the whole mass into a long bar, or rod, 3/8 of an inch square, it is then cut into proper lengths of from five to six feet; one of these pieces being made red hot is held firmly in a vice, or in a square hole, to prevent it from turning, while the other end is twisted by a brace, or by machinery, taking care that the turns are regular, and holding those parts which turn closer than others with a pair of tongs, the rod is by this means shortened to half it’s original length, and made quite round. If only two pieces are employed to form the riband, one is turned to the right, and the other to the left; these being laid parallel to each other are united by welding and then flattened; but if three square rods are used, the centre one is turned in a contrary direction to the outside ones, and this produces the handsomest figure. By these operations the alterations of iron and steel change places at every half revolution of the square rod composed of twenty-five laminae; the external layers winding round the interior ones, thus forming when flattened into a riband, irregular concentric ovals or circles. The fineness of the Damascus depends on the number and thickness of alterations; but when wound into spiral form, and united on its edges by jumping, the edges bend round and the figure is completed.
And more detail about Damascus production:
Sporting Guns and Gunpowders: Comprising a Selection from Reports of Experiments, and Other Articles Published in The “Field” Newspaper, Relative to Fire Arms and Explosives Fredrick Toms 1897
From Field Jan. 15, 1896 Vol 91, p. 91
http://books.google.com/books?id=inQCAAA...rjiY4#PPA335,M1 
