×
INTELLIGENT WORK FORUMS
FOR ENGINEERING PROFESSIONALS

Log In

Come Join Us!

Are you an
Engineering professional?
Join Eng-Tips Forums!
  • Talk With Other Members
  • Be Notified Of Responses
    To Your Posts
  • Keyword Search
  • One-Click Access To Your
    Favorite Forums
  • Automated Signatures
    On Your Posts
  • Best Of All, It's Free!
  • Students Click Here

*Eng-Tips's functionality depends on members receiving e-mail. By joining you are opting in to receive e-mail.

Posting Guidelines

Promoting, selling, recruiting, coursework and thesis posting is forbidden.

Students Click Here

Jobs

conversion of torque to force
4

conversion of torque to force

conversion of torque to force

(OP)
Can someone tell how much is the force applied by a 1.5 inch dia bolt torqued to 420 N.m (Newton.meter) ?

RE: conversion of torque to force

F = 5T/d

RE: conversion of torque to force

I use the following formula for torque:

T = F/1000 [p/2pi + u(Rm+r)]

where
T = Torque Nm
F = Bolt Load N
p = thread pitch mm
u = coeff friction (0.1 to 0.2 typically)
Rm = mean thread radius mm
r = mean nut bearing radius mm

u will vary considerably depending on type of lubricant, finish and fit of threads.

RE: conversion of torque to force

2
Looks roughly the same as the other formulas. I'd use the formula T=kdf where T is torque, k is a friction factor (commonly 0.18 for well lubed nuts and studs), and f is force you will have 61 kN or 14 kips on your bolt. Well within the allowable for most steels under ordinary temperatures.

jt

RE: conversion of torque to force

(OP)
Thank you all.

I used some on-line calculators and arrived at 5.6 Tons. Is this right ?

RE: conversion of torque to force

Well, since (depending on your definition) a ton is either 2 kips (2000 lb) or 1000 kg (roughly 10 kN) then your result of 5.6 tons is roughly 56 kN or 11 kips. Pretty close to the values I came up with above. I'd guess your on line calculator used a slightly different friction coefficient, but the results are certainly reasonable.

Keep in mind that translating torque on nuts to force on a bolt is a very rough calculation. There are too many details involved (friction/lube, tolerances, temperature, phase of the moon) to pretend that the correlation is extremely accurate. Close enough usually is. If not, use stud tensioners, direct tension indicators, etc.

jt

RE: conversion of torque to force

(OP)
Thx jte

RE: conversion of torque to force

(OP)
jte,

phase of the moon ???

Yeah, it get the picture ... it is a very rough calculation.

RE: conversion of torque to force

T = .2 * d * W

where:

T = in lb
d = nominal size of a UNC bolt (e.g. .75 for a 3/4-10 bolt)
W = lb of induced load

Red Flag This Post

Please let us know here why this post is inappropriate. Reasons such as off-topic, duplicates, flames, illegal, vulgar, or students posting their homework.

Red Flag Submitted

Thank you for helping keep Eng-Tips Forums free from inappropriate posts.
The Eng-Tips staff will check this out and take appropriate action.

Reply To This Thread

Posting in the Eng-Tips forums is a member-only feature.

Click Here to join Eng-Tips and talk with other members!


Resources