Mallet’s monster mortar, built for the Crimean War, 1853 to 1856 was designed by Robert Mallet for the primary purpose of crushing masonry arches in fortifications and the thick, rammed-earth coverings, which protected powder magazines in field fortifications with its huge, 36” shells weighing from 2,400 to 2,900 Lbs. Designed to be ship and rail transportable, it was composed of 6 major sections, the heaviest weighing 11 tons. Even the tube was divided into sections!
These sections which were designed to be gas-tight upon firing. The large breech-piece containing the powder chamber was a huge, wrought-iron, forging for maximum strength. It was not finished until the war was over, and was finally tested at Woolwich, outside London in 1857. One observer of the Woolwich ordinance tests remarked that the impact of the 2,400 Lb. “blind shell”, (shell without explosive), was shocking, and that there was a 'great disturbance' at a mile and a half as cartloads of dirt and rock were ejected from a large hole, eighteen feet deep, in hard, dry, soil.
The following is a description of the first rounds that this great mortar ever fired. Credit for these quoted descriptions is given to "The Playbook of Metals Including Personal Narratives of Visits to Coal, Copper, Lead and Tin Mines with a Large Number of Interesting Experiments relating to Alchemy and the Chemistry of the Fifty Metallic Elements", by John Henry Pepper, published by George Rutledge, London, in 1862, E. Evans, Illustrator. The following quotes are from this book:
“The limit of the strength of iron seems to have been reached in Mallet’s mammoth, 36-inch mortar, which might be called Lord Palmerston’s Pacificator. The experiments with this terrific piece of ordinance (shown in the frontispiece) have not as yet been successful, partly because it does not project the shell as far as an ordinary 13 inch mortar, and secondly, because the rings of iron or portions of the strengthening system have given way after one or two discharges; but of its power there can be no doubt, when it is remembered that the shell weighs about twenty-five hundred weight or rather more than one ton and a quarter. The momentum of such a falling mass must be enormous, and no existing fortification could withstand for any number of hours, the steady application of these shells.”
“Even failures are instructive, and , therefore, one of the accounts of the
Times of the
Trial of Mallet’s mortar is inserted here.”
“Another trial of the 36-inch mortar was made in Woolwich Marsh. The experiments commenced at 11 o’clock and terminated at 1:30, with a charge of 50 lbs. of powder, &c.(sic), which obtained a range, as on the former occasions, of 340 yards to each 10 lbs. of powder. A minute examination of the wedges, keys, rings, &c.,(sic) having been made and pronounced ‘all right’, a second charge of 60 lbs. of powder, &c.,(sic) was introduced. The second shot, like the first, was successful, the range in this instance exceeded 2000 yards, the shell alighting beyond the butt, in a ditch which separates the marsh from the adjoining property, and creating a tremendous eruption of water, black earth, &c. According to the prescribed arrangement of adding 10 lbs. of powder to each successive charge, the third charge contained 70 lbs., and although the monster gun had withstood the first two rounds well, an additional degree of caution was observed by everyone present to stand clear of its proximity at the instant the match was ignited. The effect of the third round was less successful, as one of the steel cotters broke asunder, and was rendered useless; but as the former experiments had shown the necessity of being provided against a similar casualty, the broken key was replaced, with some slight delay, with a second, wrought of malleable cast iron, supposed to be more durable. The mortar was then reloaded with an 80 lb. charge, and fired with apparent success, the shell again mounting high in the air and taking flight over 2758 yards, considerably exceeding a mile and a half. The elevation of the mortar was frequently varied, and was ultimately reduced from 48 deg. 30 min. to 45 deg. At this stage of the proceedings it was found to be impossible to carry on the experiments as one of the main stays intended to secure the various segments of the barrel of the mortar was broken, and one of the principle wedges or cotters, a foot and a half in length, had escaped.”
Mike and Tracy
Mallet's mortar at Ft. Nelson in Portsmouth, U.K.
Lathe turning the 1018 steel round to historical dimensions. The bore is bored out here to 2.730". (OOPS, thanks Lance, the correct size is 1.730")
We always make a sketch or drawing before cutting any metal or wood; it pays dividends in that this prevents most wasted material and helps figure out details.
A full radius was bored in the ball-seat area using a single point boring took every 1 deg.
The bore size is evident here; how did that 7" Brooke Treble-Banded Rifle breech get in this picture? Must have just been lying there.
