Over Sized Helicoils?

[Tinyfxds]

Ok, a few days ago I posted a topic on removing helicoils from a deep hole.  That step is complete but now we have to fix some of the holes because the company we had install the helicoils have ripped the threads out of our parts.  I have a few helicoils I can't get out as well. 

 

Has anyone used oversized helicoils?  We have some literature for Oversize and Twinserts brand inserts that will correct tapping errors to STI tapped holes for helicoils.  These inserts allow the use of the original bolt size afte the repair has been made. 

 

Do they work well?  We have to respond to our customer on what we are going to do.  It's either try these oversize helicoils or make new parts. 

[Newbeeee™]

Timeserts are good but can't remember how much oversize they are.

They are a solid insert, not a wire.

You could tap out and make your own (1/2 studding tapped through 3/8 for example) and Loctite in?

[Tinyfxds]

We are at the mercy of our customer.  This is for a medical part and must withstand 70g of force for extending periods of time.  I do not believe we manufacture something one our own.  I do see that these type of inserts have been approved by the U.S. Air Force T.O. 44H1-1-117.  Not sure what exactly this means but I may have to do some research to see if that number is a specification call out or requirement of some sort.

[Guyinthedesert]

Timeserts work great, but their OD is a standard STI thread.  I would 2nd making your own inserts, or maybe, if your customer allows, use a thin wall EZ lock

[Guest]

Have you looked into Keylocking inserts?

 

They get a larger standard tap size and the internal of the insert is a different size.

 

So a 10-32 ID would get a 5/16-18 tap, then the insert in and tabs down to lock it

 

• Internal Thread Size10-32
• External Thread Size5/16-18

 

 

http://www.grainger.com/category/key-locking-inserts/thread-insert/fasteners/ecatalog/N-8ny

[Sticky]

If you can switch to a solid insert. Hopefully there is something that meets your specifications.

 

We use lots of Ezloks and timeserts. The nice thing about solid inserts aside from being stronger, easier to re&re etc is that you can use regular course standard or metric threads for the hole they go into.

[Pilot Plant Supervisor]

The oversized Helicoils saved my bacon a few years ago. I comped out some threadmilled holes in Titanium a little too far. I bought over sized helicoils and oversized helicoil thread gages so I could control the process. Holes measured good when done, and the customer bought off on it, but man was I sweating for a while. If I remember right, they are only +.01" or so.

[Tinyfxds]

We have some holes where the threads are stripped out and some where the threads are oversized.  I'm hoping to use the Oversize helicoils first and if that doesn't work then move to the Twinsert system as a last resort. 

 

 

If you can switch to a solid insert. Hopefully there is something that meets your specifications.

 

We use lots of Ezloks and timeserts. The nice thing about solid inserts aside from being stronger, easier to re&re etc is that you can use regular course standard or metric threads for the hole they go into.

 

We would have to get clearance from the engineers at our customer.  I agree though, solid inserts would be better.