×
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

HELI-COIL in heavy duty joint

HELI-COIL in heavy duty joint

HELI-COIL in heavy duty joint

(OP)
A contractor of us broke a bit while machining a big nodular cast piece, so some M30 threads become unusable. The contractor suggest to use heli-coil to repair it, but we have some reservations about that:

- Heli-coils are usually intended for using high tensioned bolts in soft materials, but we don't have any news of their use in heavy duty cast pieces.
- The bolts to be used are high strength (10.9), high pretensioned (90%), but as far as we know usual applications of heli-coils are located in parts with low tightening requirements like covers, etc.
- The joint has a high responsability, since its failure can derive in a total destruction of a big, $500000 machine, so we don't want to take any risk...
- The joint is quite exposed to the environment, so we are not sure if the cast could be more prone to oxidize with the stainless-steel insert.

Any suggestions/advises? Any better solution to save the cast piece? Thank you in advance.

RE: HELI-COIL in heavy duty joint

I think I would prefer a heavy duty keensert
if you have the room for them.

RE: HELI-COIL in heavy duty joint

Heleicoils are awesome!  They usta use them all the time to fix "Whoopses" in turbine land [huge ones that looked like "slinkies", & also "by design" for highly loaded joints to favorably distribute the load/prevent stripping.
The only problem is they're not sealable [need blind holes] to be pressure tight.
  Look in the design charts - they're stronger than the bolt.
http://www.emhart-vic.com/emhart/sc_app/sc_description.asp?code=default&famID=30

http://www.emhart-vic.com/emhart/pdf/Main%20HC-2000.pdf

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