Helicoils and Oversize Threads

[swall]

I have run into a situation where a threaded stud that is slightly oversize is being installed in a Helicoil insert in an aluminum housing. I am thinking this is a bad idea, as the oversize stud will tend to wind the Helicoil up, thus losing the normal expansion forces that help hold it in place. What do you guys think?

 

[desertfox]

Hi swall

Is the stud within tolerance for the standard thread diameter, if so it should be okay.

desertfox

 

[mechengdude]

First suggestion:
Call the experts and ask your question. They are their to help: Emhart Technologies 203-924-4737.

http://www.emhart.com

when you say oversize do you mean out of spec. or on the high side of a thread spec.
If your threaded stud is oversized to the point that it starts moving the helicoil then you have a whole batch of other problems, galling, improper torque, etc.

Good luck

 

[zekeman]

A properly inserted helicoil cannot possibly wind up on the stud.As long as the bolt can be threaded on, there is no room for winding. Helicoil has been doing this for 60 years ( I worked for them in the 70's) and I assure you there is no problem here.

 

[swall]

The studs were intentionally made oversize to provide an interference fit when they were screwed into a tapped hole in the aluminum. With the Helicoil job, the same stud was used.

 

[Heckler]

Why not use a Keensert Insert with staking tangs?

Heckler
Sr. Mechanical Engineer
SWx 2007 SP 4.0 & Pro/E 2001
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This post contains no political overtones or undertones for that matter and in no way represents the poster's political agenda.

 

[swall]

Yes, the keylock inserts are what I have recommended.