76 



Bui.le;tin 86 



Pig 4 —Cement pipe plant at Continental, Arizona, showing the Mc Crack en No. 2 

 pipe machine and accessories, the mixer, the iack shaft, and the cement house. 

 The rameda is located at the right. 



Fig 5— McCracken packer-head for 2l!-inch cement pipe. The five vanes are fol- 

 lowed by the cylindrical trowel. 



