×
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

Looking for torques values for steel into fiberglaass

Looking for torques values for steel into fiberglaass

Looking for torques values for steel into fiberglaass

(OP)
Have project which has SS ports being threaded into fiberglass and am looking for a way to figure torques for threads not to strip out.

RE: Looking for torques values for steel into fiberglaass

The problem is of course the fact that the subject material is not homogenous.
Isn't this usually resolved by buying/fabricating a load spreading part that would be bonded/assembled to the back side with resin/mat?  This part, I guess would be threaded st. stl. or w.h.y.

"The ideal client is one possessed of great good sense and perfect judgement;
that is to say, one who agrees entirely with the designer at all times and in every respect."
               Fenwick Williams, Naval Architect.

RE: Looking for torques values for steel into fiberglaass

Equations to calculate the recommended thread engagement length (and load to failure given a fixed engagement length) can be found in Machinery's Handbook, under Fasteners, Torque and Tension in Fasteners, Formulas for Stress Areas and Lengths of Engagement of Screw Threads.  In the 25th Edition, it is on pp. 1415-1416.

pj

RE: Looking for torques values for steel into fiberglaass

(OP)
I have the 24th edition and have looked in it but am unable to find any reference to torques, fastener ot tension in fasteners. Thanks

RE: Looking for torques values for steel into fiberglaass

Buy some fiberglass nuts from either Harrington Plastics or McMaster-Carr, and do some tests on stripping. Then, compare your fiberglass to that of the nuts, do some testing on your material & allow a big safety factor.

http://www.harringtonplastics.com/
http://www.mcmaster.com/
The following info is from the McMaster-Carr online catalog:
Fiberglass—Made of urethane resin. It’s nonconductive,
flame retardant, and is resistant to mild acids, solvents, and saltwater. Working temp.: up to 212° F. Minimum Rockwell
hardness: R119. Minimum tensile strength: 27,000 psi. Strength is greater than Nylon 6/6.
http://www.mcmaster.com/
Nut materials on p. 2961, fiberglass nuts on p. 2965.

Gray
Fiberglass
Screw    Qty. Per Pkg..
1/4_-20. . .. . . 10. . . .91395A029. . . . $6.13
5/16_-18 . . .  . 10. . . .91395A030. . . . 6.13
3/8_-16. . . .  . 10. . . .91395A031. . . . 6.13
1/2_-13. . . .. . 10. . . .91395A033. . . . 8.74
5/8_-11. . .. .  . 5. . . .91395A035. . . . 6.90
3/4_-10. . ..  . . 5. . . .91395A036. . . . 8.60
7/8_-9 . . . . -- . . .------------- .      . ---- .
 1_-8. . . . . . . 1. . . .91395A038. . . . 2.26

I think the Harrington Plastics Engineering book (not the catalog) gives torques for various sizes of fiberglass nut & bolt combinations, but of course, your material may differ.

RE: Looking for torques values for steel into fiberglaass

Stubby - what is the application - ie what is the physical envelope of the fiberglass?  What is the fiberglass structure?

I'd be happy to help if I knew more....

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