﻿30 BULLETIN 23, U. S. DEPARTMENT OF AGRICULTURE. 



Item 5. storage and care of samples . — Samples must be carefully handled to avoid 

 breakage or injury. They must be kept dry so far as practicable. If wet when 

 received, or known to have been immersed or subjected to recent prolonged wetting, 

 they shall be dried for at least six hours in a temperature of 100° Fahienheit before 

 testing. 



THE CONSTRUCTION OP THE RATTLER. 



Item 6. The machine shall be of good mechanical construction, self-contained, and 

 shall conform to the following details of materials and dimensions, and shall consist 

 of barrel, frame and driving mechanism as herein described. Accompanying these 

 specifications is a complete drawing (PI. X) of a rattler which will meet the require- 

 ments, and to which reference should be made. 



Item 7. The barrel. — The barrel of the machine shall be made up of the heads and 

 headliners, and staves and stave-liners. 



The heads may be cast in one piece with the trunnions, which shall be 2\ inches 

 in diameter, and shall have a bearing 6 inches in length, or they may be cast with 

 heavy hubs, which shall be bored out for 2xVinch shafts, and shall be keyseated for 

 two keys, each \ inch by f inch and spaced 90 degrees apart. The shaft shall be a 

 snug fit and when keyed shall be entirely free from lost motion. The distance from 

 the end of the shaft or trunnion to the inside face of the head shall be 15| inches in the 

 head for the driving end of the rattler, and llf inches long for the other head, and the 

 distance from the face of the hubs to the inside face of the heads shall be h\ inches. 



The heads shall be not less than £ inch nor more than \ inch thick. In outline, each 

 head shall be a regular 14-sided polygon inscribed in a circle 28f inches in diameter. 

 Each head shall be provided with flanges not less than f inch thick and extending 

 outward 2\ inches from the inside face of the head to afford a means of fastening the 

 staves. The surface of the flanges of the head must be smooth and must give a true and 

 uniform bearing for the staves. To secure the desired true and uniform bearing the 

 surfaces of the flanges of the head must be either ground or machined. The flanges 

 shall be slotted on the outer edge, so as to provide for two f-inch bolts at each end of 

 each stave, said slots to be -fl inch wide and 2| inches, center to center. Each slot 

 shall be provided with a recess for the bolt head, which shall act to prevent the turning 

 of the same. Between each two slots there shall be a brace f inch thick, extending 

 down the outward side of the head not less than 2 inches. 



There shall be for each head a cast-iron headliner 1 inch in thickness and conform- 

 ing to the outline of the head, but inscribed in a circle 28-g- inches in diameter. This 

 headliner shall be fastened to the head by seven f-inch cap screws, through the head 

 from the outside. Whenever these headliners become worn down \ inch below their 

 initial surface level at any point of their surface, they must be replaced with new ones. 

 The metal of these headliners shall be" hard machinery iron and should contain not less 

 than 1 per cent of combined carbon. 



The staves shall be made of 6-inch medium steel structural channels 27£ inches long 

 and weighing 15.5 pounds per lineal foot. The staves shall have two holes ^| inch 

 in diameter, drilled in each end, the center line of the holes being 1 inch from the end 

 and \\ inches either way from the longitudinal center line. The spaces between the 

 staves shall be as uniform as practicable, but must not exceed -£% inch. 



The interior or flat side of each stave shall be protected by a liner f- inch thick by 

 5J inches wide by 19f inches long. The liner shall consist of medium steel plate and 

 shall be riveted to the channel by three £-inch rivets, one of which shall be on the 

 center line both ways and the other two on the longitudinal center line and spaced 

 7 inches from the center each way. The rivet holes shall be countersunk on the face 

 of the liner and the rivets shall be driven hot and chipped off flush with the surface 

 of the liners. These liners shall be inspected from time to time, and if found loose 

 shall be at once reriveted, but no liner shall be replaced by a new one except as 

 the whole set is changed. 



