Distributor's Link Magazine Fall 2020 / Vol 43 No 4
44 THE DISTRIBUTOR’S
44 THE DISTRIBUTOR’S LINK Anthony Di Maio Anthony E. Di Maio attended Wentworth Institute and Northeastern University. In 1962 he started working with Blind Fasteners as Vice-President of Engineering & Manufacturing for two blind rivet manufacturers. He has been Chairman of the Technical Committee of the Industrial Fasteners Institute (IFI) and is still involved in the writing of IFI specifications. In 1991, he started ADM Engineering and is working with Fastener Manufacturers developing new fasteners and special machinery. He can be reached at ADM Engineering, 6 Hermon Ave., Haverhill, MA 01832; phone and fax 978-521-0277; e-mail: tdimaio@verizon.net. BLIND RIVETS HAVE THREE DIMENSIONAL SYSTEMS [1] Inch System Inch system is the system mostly used in the USA. This system incorporates the diameter of the blind rivet and the blind rivet maximum grip range in it’s part number. Example:- 64 size blind rivet. 6 equals the diameter of the blind rivet and is the first number of the blind rivet part number. This first number, which in this illustration is 6 and this number has a base factor of 1/32. Therefore, 1/32 X 6= 6/32 reduced =3/16. A 6 diameter blind rivet is a 3/16 diameter blind rivet. The second number 4 has a base factor of 1/16. Therefore, 1/16 X4=4/16 reduced =1/4. A 64 size blind rivet has a maximum grip range of 1/4. This means that a 64 size blind rivet is a 3/16 diameter blind rivet that can fasten components having a maximum thickness of 1/4 inch. When calculating both diameter and maximum grip range, always reduce the fraction to the lowest denominator. Example:- 6/32 = 3/16 and 4/16 = 1/4,both 6/32 and 4/16 have been reduced to their lowest denominators. As you can see the length “ L” of the blind rivet has no relationship to the blind rivet part number. Now the question is, “what is the grip range of a blind rivet that is in my hand” Let us assume you have a size 64 blind rivet in CONTRIBUTOR ARTICLE your hand. A size 64 blind rivet has a maximum length “ L“ of .450. if you measure the “ L” dimension of the 64 rivet in your hand and you find that “ L” is .437, then subtract one rivet diameter from .437 - .187 = .250. 250 equals 1/4 and this is the maximum grip range of the blind rivet in your hand. You then measure the diameter and you find that the diameter measures .187. therefore, you have a 3/16 diameter blind rivet with a .250 maximum grip range. Now you know the blind rivet is a 64. Let us calculate another size blind rivet. A size 410. The first number 4 has a base factor of 1/32, 4 X 1/32 = 4/32 reduced, is 1/8. Therefore, a 410 is a 1/8 diameter blind rivet. 10 is the maximum grip range with a base factor of 1/16, 10 X 1/16 = 10/16 reduced, = 5/8 equals the maximum grip range. Again, holding the blind rivet in your hand and not knowing the maximum grip range. IFI-114 shows length “L” in their specification and it shows “L” maximum is .775. You measure the length of the rivet body and you find that it is .750. Subtract the diameter of the blind rivet .125 from .750. 750-.125=.625 = 5/8 maximum grip range. You then measure the diameter of the blind rivet and you get .125. This is a 410 blind rivet. [2] Soft Metric Soft metric is sometimes used here in the USA. Soft metric is when the inch dimension numbers are directly converted to the metric equivalent. Example:- rivet size 64 which we know is a 3/16 diameter rivet having a 1/4 maximum grip range. 3/16 is converted to metric which is 4.8mm and the maximum grip range of 1/4 will read 6.4mm. CONTINUED ON PAGE 122
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