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Indiana University Studies 



equipped with four tool heads so that the sides as well as the top 

 of the stone can be smoothed at one trip of the platen. Bi- 

 planers have the advantage over the others in that two stones 

 can be worked separately and independently of each other. 

 They are, in fact, like two single-side planers placed with their 

 open sides together. The two planes are independent of each 

 other in height as well as travel. In the type known as the 

 ' 'circular planer" the table is arranged so that it can travel 

 either in a circle or in a straight line, thus securing planing along 

 curved lines as well as straight travel. Any radius of curvature 

 desired can be secured with a little adjustment. There are many 

 special types of planers constructed for special work that need 

 no description here. 



The lathe is a machine for turning out column work and can 

 be purchased in any size desired. The lathe for heavy column work 

 must be very heavy in construction since it is necessary to carry 

 very large columns on a single point of support. The column 

 is usually quarried and roughed out by hand to within a few inches 

 of the desired size. Steel centers are then inserted in the ends of 

 the column. The work of turning is done by cutters made with 

 a beveled edge out of specially hardened steel. These travel 

 along the sides of the column as it revolves and take off the rough 

 surface of the stone. Some lathes will turn out columns up to 

 24 feet in length and from 36 to 66 inches in diameter. Special 

 attachments for fluting are used with the lathes. 



The wire saw is used in only two of the mills in this district, 

 but has a very extensive use in foreign countries. It consists of 

 a twisted cord of steel made to run around pulleys like a band 

 saw. The cord is composed of three steel wires twisted loosely 

 together, but stretched tightly over the pulle3^s, and made to 

 run at a high rate of speed. The swift blows delivered by the 

 ridges in the cord wear away the stone more rapidly than the 

 smooth blades of the gang saws fed by sand. 



Pneumatic appliances are in use in all the more up-to-date 

 mills, and the use of the hand hammer in carving limestone 

 has nearly disappeared. The work can be done so much more 

 rapidly and cheaply by compressed air that every plant of any 

 size is equipped with an air compressor and air hammers. The 

 compressed air is carried to the hammers thru flexible tubes. 

 The hammer consists of a valve and piston arrangement, giving 

 a striking action of over 3,000 blows per minute, the tool being 

 inserted against the piston. The speed and force of the blows 



