450 



MEMOIU OF DANIEL TREADWELL, 



" The hoop may be stretched by this last operation the j-b*^ P^^* °^ ^^^ diameter, and, if it is 

 made of very soft and tou.trh iron and has not been hammered very hard, much more than this 

 quantitv. Tlie extent, however, to which this hammering and cold stretching may be carried, 

 must depend upon the quality of the iron and the heating and working to which it has been 



Fig. 4. 



Fio. 3. 



previously subjected. It will be well, when the stretching is commenced, to have the hoop 

 warmed up to 200° or 300°. 



" After the hoop has been prepared in this way by cold hammering and stretching, it is to be 

 bored and turned ; and, whether it is to be fixed to the gun by a screw-thread, or by any equiva- 

 lent, it is to be carefully and equably heated to such a temperature (but never up to an annealing 

 heat) as shall expand it sufliciently, and, in this state, is to be placed upon the gun."* 



" In the Specification and Memoir before mentioned, I propose to form the screw ' of about 

 eight threads, each thread taking about one eighth of an inch space, so tliat one turn advances 



* The method of makiiiij the rings and applying them is that followed in making the trnnnion-ljands in 1841-44, 

 and for the same reasons, — for secnring them and strengthening the guns. It is thus described by Mr. Treadwell : 

 "All these guns that wore finished had trunnion-bands screwed upon them by which the trunnions were secured to 

 the gun. In order to utilize the strength of the trunnion-band against the force of the discharge of the powder, and 

 to bring it in as an addition to the thickness of the body of tlie gun, the inside of the trunnion-band was in all 

 cases made smaller than the body of the gun at the place upon which it was screwed. None of them could be got 

 into their places when cold. They were therefore all heated to a small degree, and run on to the gun to their places 

 while under the expanding influence of this heat. . . . The band, in each case, was taken across the road to the 

 blacksmith's shop, and there warmed up, never to a red heat in any case. I should think always 500°, never 900°. 

 No iron bars or tools were used in handling them, but the men took hold of them with cloth, and aprons, or anything 

 of that kind which would defi'ud the hand from the warm iron. I do not recollect ever seeing a cloth burnt in 

 the operation." See Daniel Treadwell vs. Robert P. Parrott, United States Circuit Court, Southern District of New 

 York, 1864. 



