Machinery's Encyclopedia; A Work of Reference Covering Practical Mathematics and Mechanics, Machine Design, Machine Construction and Operation, ... Machinery, Metallurgy, and Kindred Volume 3 - Erik Oberg, Paperback

• Release Date   9/13/2013
• ISBN-13   9781236817075 | 978-1-236-81707-5
• ISBN   1236817079 | 1-236-81707-9
• Format   Paperback
• Author(s)   Erik Oberg
• This historic book may have numerous typos and missing text. Purchasers can usually download a free scanned copy of the original book (without typos) from the publisher. Not indexed. Not illustrated. 1917 edition. Excerpt: ...as shown by a reference gage. Sketch B illustrates another form of snap or caliper gage. This type is double-ended and is intended for Fig. 3. Limit Gages equipped with Bufiers to prevent Peening Action when Gage strikes Work correct for the particular class of fit required. (See FIT ALLOWANCES FOR Macnms PARTS.) Another extemal limit gage is shown at B, Fig. 2. Nominally this is a-inch gage. The size of the "go" end is 0.250 inch and the size of the " not go" end is 0.2485 inch. hence, the tolerance is 0.0015 inch. Therefore, a part that is more than 0.0015 inch less than 0.250 inch will pass the "not go" end of the gage and is smaller than the required size. An internal limit gage is shown at C. The nominal size of this particular gage is 1 inch. The diameter of the " go" end is 1.2492 inch, whereas the diameter of the "not go " end is 1.2506 inch. hence, in this case, the tolerance equals 1.2506--1.2492 = 0.0014 inch. Incidentally, it is good practice to make all holes to standard sizes within whatever limits may be advisable, and vary the size of the cylindrical parts to secure either a forced fit, running fit, or whatever class of fit may be required. It will be noted that the ends of these limit gages are of different shape so that the large and small sizes can readily be identified without referring to the dimension stamped on the gage ends. Limit gages are very generally used for the final inspection of machine parts, as well as for testing sizes during the machining process. They are superior to the micrometer for many classes of inspection work, because the adjustment and reading necessary with a micrometer often results in slight variations of measurement, especially when the...