Distributore BUMAX ITALIA
Viti Bulloni Alta Resistenza Meccanica

VITI BULLONI TESTA ESAGONALE ANSI B 18.2.1 – Bumax 88



Thread

d UNC 1/4 5/16 3/8 1/2 5/8 3/4 7/8 1
No. of threads per inch - 20 18 16 13 11 10 9 8
s inch - 7/16 1/2 9/16 3/4 15/16 1.1/8 1.5/16 1.1/2
s mm - 11.1 12.7 14.3 19 23.8 28.6 33.3 38.1
k - 4 5.2 6 7.9 9.9 11.9 13.9 15.5
e (min) - 12.39 14.15 15.95 21.34 26.69 31.85 37.21 42.55
Length of thread engagement b for 1 to 152 - 19 22 25 32 38 44 51 57
Over 152 - 51

Bolt length l Approximate weight per 100

inch mm kg kg kg kg kg kg kg kg
1/2 13 0.56 0.95
5/8 16 0.62 1.1 1.5
3/4 19 0.66 1.1 1.6
7/8 22 1.7
1 25 0.79 1.3 1.9 3.8 6.8
1.1/4 32 0.97 1.5 2.2 4.4 7.7 12
1.1/2 38 1.1 1.8 2.5 4.8 8.5 13 20
1.3/4 45 1.3 2.0 2.9 5.6 9.4 15
2 51 1.4 2.3 3.3 6.2 10 16 24 33
2.1/4 57 3.6 6.7 11 17 35
2.1/2 64 1.7 2.8 3.9 7.5 12 19 27 37
2.3/4 70 4.3 8.1 13 20 29
3 76 2.0 3.2 4.7 8.7 14 21 31 42
3.1/4 83 5.0 9.2 15 23 33
3.1/2 89 3.7 5.3 10 16 24 35 47
4 102 4.3 6.1 11 18 27 39 52
4.1/2 102 6.7 12 20 30 42 57
5 114 7.4 14 23 33 46 61
5.1/2 140 8.2 15 24 36 50 67
6 152 8.7 16 26 38 54 71
6.1/2 165 41
7 178 44
Nut type
BUMAX 88-U6M
0.32 0.47 0.69 1.6 3.2 5.3 9.2 14

Sample order: Above stepped line 931U BUMAX 88.

The rest: 933U Bumax88 1/4×19

Screws above the stepped line are fully-threaded.