12 
BULLETIN 661, U. S. DEPARTMENT OF AGRICULTURE. 
The trucks for holding the drying trays are made of surfaced 
2 by 4 inch lumber, or other suitable material, the same size as the 
trays, and have mortised joints and a swivel caster at each corner. 
Strong and serviceable trucks can be made complete for $2.50 each. 
Much cheaper trucks can be made, of course, but it is doubtful whether 
they would prove to be more economical in the end. The number of 
trucks and trays needed depends to a large extent upon the time in 
which the casein is to be dried. Twelve wooden trucks and 30 dozen 
trays should be available to handle 15,000 pounds of buttermilk 
daily. By loading them more heavily, more buttermilk can be 
Fig. 3. — Screen-covered drying trays and caster trucks used in drying the ground curd. 
handled with the same number of trays, but in this case the time of 
drying is materially increased. 
CUED MILL. 
The importance of getting the right kind of curd mill, which is 
used to grind the green curd taken from the press, can not be over- 
estimated. If the curd is not ground properly the most favorable 
drying conditions can not be obtained. In order to do satisfactory 
grinding the mill should have both the shredding and beating fea- 
tures possessed by the better machines (see fig. l). The shred- 
ding part consists of a comparatively slow -revolving cylinder fitted 
with sharp-peg teeth to tear the large masses of curd into small pieces 
