IRON HOOPS FOR SILOS. 61 



to one of the posts originally set. Immediately a stave is set in 

 place it should be toe-nailed at the top to the preceding stave set. 

 It has been found that the work of setting up and preserving the 

 circular outline may be materially aided by the use of old barrel 

 staves (see Pig. 18). For a silo 12 feet in diameter the curve in 

 the stave of the sugar barrel is best adapted; for a 16-foot silo 

 the flour barrel stave is best, and for a silo 20 feet or more in 

 diameter the stave of the cement barrel is best. If when the silo 

 staves are put in place they are toe-nailed securely to the ones 

 previously set if they are fastened firmly to the permanent up- 

 right post (Fig. 17, a, a, a, a) ; if the barrel staves are used as 

 directed above, the silo will have sufficient rigidity to stand until 

 the hoops are put in place. However, if it becomes necessary for 

 any reason to delay for any considerable time the putting on of 

 the hoops, boards should be nailed across the top of the silo. 



When it is found Impossible to secure staves of the full length 

 desired, a. joint or splice must be made. 



For a silo 30 feet deep, staves 20 feet in length may be used. 

 A part of these should be used their full length and part should 

 be sawed through the middle, thus making staves of 20 and 10 

 feet length. In setting them ift) the ends which meet at the splice 

 should be squared and toe-nailed securely together. They should 

 alternate so that first a long stave is at the bottom then a short 

 one, thus breaking joints at 10 feet and 20 feet from the base. 



For the hoops, %-inch round iron or steel rods are recom- 

 mended, although cheaper substitutes have been found satisfac- 

 tory. Each hoop should be in three sections for a silo 12 feet in 

 diameter, in four sections for a, silo 16 feet in diameter. If the 

 method of construction shown in Fig. 17 is followed, the hoops 

 will need to be in four sections each, the ends being passed 

 through the upright 6x6 posts, and secured by heavy washers and 

 nuts. The bottom hoop should be about six inches from the base 

 of the silo; the second hoop shbuld be not more than two feet 

 from the first; the third hoop two and one-half feet from the 

 second, the distance between hoops being increased by one-half 

 foot until they are three and one-half feet apart, which distance 

 should be maintained except for the hoops at the top of the silo 

 which may be four feet apart. The hoops should be drawn fairly 

 tight before the silo is filled, but not perfectly tight. They must 

 be tight enough to close up the space between the staves, thus 



