88 



Buivi^ETiN 86 



the forms for a third pipe are being made ready. The table has a 

 socket bearing at the center, about 1^ inches diameter, resting on a 

 spindle so that it turns easily when the operator raises the spindle 

 by stepping on the end of a foot lever. About ten of these machines 

 are now in use. The range of sizes is from 6 to 14 inches in 

 diameter. 



THE KElvIvAR-THOMASON 



The Kellar-Thomason machine is larger and requires a 20-horse- 

 power engine or motor. The machine is quite similar to the Mc- 



Fig. 12. — The Kellar-Thomason pipe machine. 



Cracken and uses the trowelling process, but is more compact and 

 of sturdy construction, as seen in Fig. 12. 



The ordinary split jacket for hand-tamped pipe is used, but no 

 core, and the mortar is packed securely against the jacket by the 

 winged trowel. The usual crew is five men for small pipe and 

 seven men for large pipe. The range of pipe sizes is from 4 to 20 



