Question

Familiarity with basic fastener properties: For each of the standard fasteners specified informally below, determine the major diameter d, the pitch p, the pitch diameter dp, and the bolt length L. For bolts only, also find the threaded length LT and the proof strength Sp. Refer to Tables 8-1, 8-2, and 8- 9 through 8-11. (Some quantities are straightforward lookup, some require simple arithmetic.) a. 5/8"-11 x 2-1/4" SAE grade 5 hex bolt b. #12-28 x 3" SAE grade 5 machine screw c. M10 x 1.25 mm x 40 mm class 9.8 hex bolt d. 1¼ in.-12 x 7 in ASTM A490 type 1 hex bolt.

Answer 1

Answer:

a) 5/8"-11 x 2-1/4" SAE grade 5 hex bolt

Major Dia, D = 5/8” = 0.625”

Threads per inch (TPI) = 11

Pitch, P = 1 / TPI = 1/11 = 0.091”

Length , L = 2-1/4”

Pitch diameter , Dp = D – 0.75*cos30*p = 5/8 – 0.64952*0.091 = 0.5659”

Threaded length , Lt = 1.5” {from tables}

Proof Strength, Sp = 85 ksi for grade 5 {from tables}

b) #12-28 x 3" SAE grade 5 machine screw

Major Dia, D = 0.060" + (numbered diameter) * 0.013 = 0.060 + 12x0.013 =0.216”

Threads per inch (TPI) = 28

Pitch, P = 1 / TPI = 1/28 = 0.0357”

Length , L = 3”

Pitch diameter , Dp = D – 0.75*cos30*p = 0.216 – 0.64952*0.0357 = 0.1928”

c) M10 x 1.25 mm x 40 mm class 9.8 hex bolt

Pitch, P = 1.25mm

Length , L = 40mm

Pitch diameter , Dp = D – 0.75*cos30*p = 10 – 0.64952 x 1.25 = 9.19mm

Threaded length , Lt = 26mm {from tables}

Proof Strength, Sp = 650 MPa for grade 9.8 {from tables}

d) 1¼ in.-12 x 7 in ASTM A490 type 1 hex bolt

Major Dia, D = 1-1/4” = 1.25”

Threads per inch (TPI) = 12

Pitch, P = 1 / TPI = 1/11 = 0.083”

Length , L = 7”

Pitch diameter , Dp = D – 0.75*cos30*p = 1.25 – 0.64952*0.0833 = 1.196”

Threaded length , Lt = 3” {from tables}

Proof Strength, Sp = 120 ksi for type 1 {from tables}

Explanation: