Does a 2-1/2 û 4 UNC ôHelicoilö Exist?

[TorsionalStress]

I’m designing a plate that needs to have holes tapped at 2-1/2” – 4 UNC, but I’m thinking of using inserts, does anyone know if this size exists?

Any response will be greatly appreciated!

 

[CoryPad]

That is not a standard size produced by Emhart - they only go up to 1-1/2".

 

[unclesyd]

My guess is no, as the largest size I've seen for a wire insert is 1 1/2" UNC.

If my recall is any good I was told that above the 1 1/2" diameter they become ineffective and unworkable.

If possible could you post the reasoning behind your requirement for a Helicoil. Also the details of what you are attempting to accomplish.

 

[TorsionalStress]

The reasoning behind using a “HELICOIL” 2-1/2 - 4 UNC, is that work pieces that will be machined in a fixture have 2-5/8” thru holes. The bolts will go through lots of tightening & loosening cycles.

 

[unclesyd]

A machine insert would be one way to go but the make and break aspect kinda rules this approach out.
Would it be possible to use pins and smaller fasteners to carry the tension load?
Again is it possible to use a set-in stud and nut?

A little more information would probably get more replies.
What is the plate material?
What is the fastener material and what is the desired preload on it?

Would it be possible to post a print or sketch?

 

[saberblue]

Look at thread milling with proper programing you should be able to make any thread you desire

A.R. "Andy" Nelson
Engineering Consultant
anelson@arnengineering.com

 

[ornerynorsk]

Make your own replaceable inserts if you think the threads will wear prior to the rest of the fixture.

 

[unclesyd]

Them brain things again.

You might want to take a look at ring locked insert. This one is from ALCOA one of several manufacturers that have this type insert.

http://www.alcoa.com/global/en/products/product.asp?prod_id=480

 

[TeunisTVM]

Could you tell where the thread is placed and on which condition's. There are several solutions but white this information we can provide you the proper one

Signature: I'm Dutch and I'll do my best to write my English correctly

 

[mfgenggear]

what type of plate & what hardness?

 

[unclesyd]

You might want to give the Full Torque people a call. They have inserts up to 2" listed.

http://fulltorque.com