On the Cutting of Steel by Soft Iron. 73 



ON THE CUTTING OF STEEL BY SOFT IKON. 



At page 336, volume vi. of this Journal, (Philosophical 

 Magazine, vol. Ixii. p. 317,) the remarkable fact that soft iron, 

 in rapid revolution, will cut the hardest steel, is described 

 by the Rev. Herman Daggett. This fact does not appear, 

 as far as I am informed, in books ; nor have I found that it 

 was before known to practical men. It seems to have been 

 discovered by the Shakers, who are remarkable for the neat- 

 ness and expertness of their mechanical operations. As it is 

 desirable that the experience of others on this subject should be 

 made known, I will now add, that in June last I saw Professor 

 Robert Hare at Philadelphia execute with a common foot 

 lathe operations similar to those described by Mr. Daggett : 

 they were however less energetic and decisive, as the machine 

 did not produce so rapid a motion as that of Mr. Barnes. 



I have, however, since repeatedly seen the experiment suc- 

 ceed, in the most perfect manner, at the manufactory of arms 

 belonging to Eli Whitney, Esq. near this town [New Haven, 

 Connecticut]. As water power is here applied with great 

 facility and energy, a wheel of soft and very thin plate iron, 

 six inches in diameter, and furnished with an axis, was made 

 to revolve with such rapidity that the motion became en- 

 tirely imperceptible, and the wheel appeared as if at rest. 

 When pieces of the best and hardest steel, such as files, and 

 the steel of which the parts of gun-locks are made, were 

 held against the edge of the revolving soft iron plate, they 

 were immediately cut by it, with a degree of rapidity which 

 was always considerable, but which was greater as the pieces 

 of steel were thinner ; pieces as thick as the plate of a com- 

 mon joiner's saw, were cut almost as rapidly as wood is cut 

 by the saw itself. Considered as an experiment merely, it is 

 a very beautiful one, and in no degree exaggerated in Mr. 

 Daggett's account: there is a very vivid coruscation of sparks, 

 flying off in the direction of tangents to the peripheiy of the 

 cutting; wheel and an intense ignition of the steel, extending 

 for a considerable distance ahead of the ^section, and on its 

 sides, attends the operation. The impulse against the steel 

 is so strong, that in several instances it was thrown against 

 the opposite side of the room with a velocity that might not 

 have been without danger to a person standing in the way. It 

 may be said, I believe, with safety, that none of the ordinary 

 mechanical operations commenced upon cold and hard steel, 

 will divide it with so much rapidity as this mode of applying 

 soft iron. After all, it is evident that it is only a peculiar me- 

 thod of cutting red-hot, or possibly white-hot steel ; for the 

 mechanical force produces these degrees of heat, and it is one 



Vol. 64. No. 315. July 1824-. K of 



