82 



Bui^le;tin 86 



pipe was "carbonized" in kilns with coke gas and steam and it is 

 said that three days in the kiln were equal to two weeks of curing in 

 air. Prior to the advent of the Sherman machine, all the sewer pipe 

 used in Brooklyn was made by hand tamping, using natural, or 

 "Rosendale," cement. 



the; schenk 



A pipe machine which has been used extensively in Iowa and 

 neighboring states is the Schenk, made at Waterloo, Iowa. This 

 was the pioneer tile machine, the first one having been built in 1906. 

 It was the first centrifugal packer, and, as might be expected, was 

 troublesome to operate at first, but many improvements have been 

 introduced and the Schenk has become entirely reliable. 



The principles of the Schenk ma- 

 chine are very similar to those of the 

 McCracken, the differences being in 

 the mechanical details. The packer 

 shaft is rotated by gearing and is ele- 

 vated by a lever the rear end of which 

 is controlled by a heart-shaped cam 

 wheel, which in turn is operated by 

 worm drive from the main shaft. The 

 original Schenk packer-head was 

 shaped like an ordinary earthen jug, 

 but the one now in use has vanes 

 and a cylindrical trowel exactly like the McCracken. 



The range of sizes possible with the regular No. 2 Schenk ma- 

 chine is from 4 inches to 18 inches, with lengths of either 12 or 18 

 inches. There is also a Schenk sewer pipe machine with range of 

 sizes from 4 to 30 inches, and in length either 24 or 30 inches. The 

 Schenk is said to be a very fast machine for the smaller sizes of tile. 

 The manufacturers guarantee that it will make 3000 feet of 6-inch 

 straight tile per day with six men. It is not known that they have 

 yet furnished pallets for tongue and groove pipe, but doubtless 

 would do so if the demand warranted it. 



Fig. 8. — The Schenck packer- 

 head, showing trowel and wings. 



THE NATIONAL 



A pipe machine, called the National, made at Boone, Iowa, dif- 

 fers from the two preceding in that both outside and inside forms 

 are used and the mortar is tamped in place. It is adapted to making 

 large pipe, particularly from 20-inch to 45-inch, though the range 



