Automatic Machine Gaging 



By C. W. ROBBINS 



Note: This paper discusses the advantages to be gained in certain types 

 of large scale production by the substitution of automatic machine gaging 

 for hand testing. For testing carbon protector blocks, a machine has been 

 developed which accepts all blocks in case a certain dimension lies between 

 0.0024" and 0.0032" and rejects those when the dimension is 0.0023" or 

 less or 0.0033" or more. This machine will effect a saving of $8000 per 

 year over the cost of hand gaging on an output of 4,500,000 blocks. The 

 saving effected by another recently developed machine replacing a manual 

 test is approximately $1200 a year on a production of 2,500,000 pieces, but a 

 far more important consideration than this money saving is the elimination 

 of an operation so monotonous that it was difficult to keep any operator on 

 it for more than a brief period. The author points out that in some in- 

 stances automatic machine gaging of the entire product will cost less than 

 a sampling inspection in which there must be included in the direct cost of 

 inspection the cost of some additional supervision and control. 



THE cost of testing and gaging parts manufactured in large 

 quantities frequently warrants the construction of special ma- 

 chinery for this work which may be more or less automatic in operation. 

 At the Hawthorne Works of the Western Electric Company con- 

 siderable study has been given to the problem during the past ten or 

 twelve years and several such machines have been developed. The 

 work has recently assumed more important proportions and many 

 important developments have materialized in the last two or three 

 years. 



Some of these machines perform a single operation while others 

 perform several operations successively. Some are automatically fed 

 from a hopper; others are fed by an operator, who at the same time 

 performs some visual operation. Usually each type of piece to be 

 gaged forms a distinct problem, and a single paper to be most useful 

 can be suggestive only as to the procedure to be followed and methods 

 that may be used. To this end it seems best to describe with con- 

 siderable detail some of the machines that are in successful operation. 



Single Test Machine, Automatic Feed 



A single purpose gaging machine with automatic feed is shown in 

 Figs. 1 and 2. The part to be tested, shown in Fig. 2 (a), is used in the 

 construction of switchboard plugs. It consists of a piece of 5/32 in. 

 brass tubing, 1^ in. long, having a sleeve soldered at one end and a 

 plug soldered in the other. The machine applies a 50 pound test to 

 the two soldered joints simultaneously. 



Within the hopper H, Fig. 1, a shaft having three slotted arms is 



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