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

thread behavior mystery

thread behavior mystery

thread behavior mystery

hi all,

i am wondering about physics of this situation

we have 3 screws: DIN 912 M6x30, 8.8 zinc, 10.9 zinc and 12.9 black
we are fastening them to steel high nut (around 15 mm height) thru a steel plate

now the results are:
1) 8.8 zinc screw - bolt is broken around 18 Nm, thread in nut and screw thread are ok
2) 10.9 zinc screw - nut thread is damaged @ around 21 Nm, screw thread is ok
3) 12.9 black screw - everything is ok at 30 Nm

different results at different classes, however why 12.9 didn't destroyed nut thread?.... the only reason I find here is an external diameter of screw which was around 0.1 higher than other classes (5,93 comparing to 5,83)

thanks for useful tips

RE: thread behavior mystery

one more thing: consider experiment environment at the same level (same fricition etc.)

RE: thread behavior mystery

You can't assume friction is the same. Perhaps the 10.9 screw had lower friction and developed higher force which damaged the internal thread.

RE: thread behavior mystery

Frictional properties between zinc electroplate and black oxide are very different.

It is better to have enough ideas for some of them to be wrong, than to be always right by having no ideas at all.

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! Already a Member? Login


White Paper - Strategies to Secure Connected Cars with Firewalls
White-hat hackers have demonstrated gaining remote access to dashboard functions and transmissions of connected vehicles. That makes a firewall a vital component of a multilayered approach to vehicle security as well as overall vehicle safety and reliability. Learn strategies to secure with firewalls. Download Now
White Paper - Model Based Engineering for Wire Harness Manufacturing
As complexity rises, current harness manufacturing methods are struggling to keep pace due to manual data exchanges and the inability to capture tribal knowledge. A model-based wire harness manufacturing engineering flow automates data exchange and captures tribal knowledge through design rules to help harness manufacturers improve harness quality and boost efficiency. Download Now
White Paper - What is Generative Design and Why Do You Need It?
Engineers are being asked to produce more sophisticated designs under a perfect storm of complexity, cost, and change management pressures. Generative design empowers automotive design teams to navigate this storm by employing automation, data re-use and synchronization, and framing design in the context of a full vehicle platform. Download Now
eBook - Simulation-Driven Design with SOLIDWORKS
Simulation-driven design can reduce the time and cost of product development. In this engineering.com eBook, we’ll explore how SOLIDWORKS users can access simulation-driven design through the SOLIDWORKS Simulation suite of analysis tools. Download Now

Close Box

Join Eng-Tips® Today!

Join your peers on the Internet's largest technical engineering professional community.
It's easy to join and it's free.

Here's Why Members Love Eng-Tips Forums:

Register now while it's still free!

Already a member? Close this window and log in.

Join Us             Close