An air gap between helicoil and mating part 5

[elinah34]

Hey everyone,
I have 2 mating parts, and the interface is a sphere surface.
In the lower part there are helicoils (marked with red pen), and for creating an axisymmetric 120 deg chamfer for installing the helicoil there is a need to create a small planar face as shown in the picture (a small planar surface above the helicoil).
As a result the helicoil isn't right below (and hence "supported" by) the upper part's mating surface, but it is a little bit deepened, and I am wondering if it may lead to a failure.
I haven't encountered such a design, and hence need your help, experience and opinion.

Thanks!

 

[elinah34]

Thank you all!

mfgenggear
Is using threaded insert in Titanium (6Al4v) a common practice? I designed custom T nuts for structural elements, and never used any threaded insert. My design was formally reviewed, checked and approved by several experienced engineers and no one suggested it.
Is using a threaded insert in titanium recommended as in the case of aluminium?

 

[3DDave]

How did it go from Ultem 1000 to Titanium?

One use for threaded inserts is they can incorporate self-locking features and can provide a more favorable dis-similar metal contact, particularly key-locked inserts, which can be installed with corrosion control materials.

 

[elinah34]

Ultem 1000 is still there.

I just asked mfgenggear why he said he uses helicoil in titanium.

 

[TugboatEng]

Both aluminum and bare titanium are very sensitive to galling. Inserts offer many benefits beyond strength alone. I have a few projects with Nitronic 60 inserts 316SS flanges so I can skip the anti-seize when using 316 bolting.

 

[mfgenggear]

yes exactly , typically when the bolts seize, the threads rip out, fail, helicoils and keensert help.

 

[elinah34]

Is there any risk when using alloyed titanium, 6Al4V? As I know, there shouldn't be a problem of stripping or galling when using this alloy.

By the way, I also want to use Nitronic 60 helicoil, so I will not be sensitive to which screw will be actually assembled and be afraid of cold welding. Unfortunately I found out that this type of helicoil isn't on stock and there is no even one manufacturer that agrees to buy them as long as he has to order less than 2000 pieces.

 

[TugboatEng]

Olander Company stocks Nitronic 60 helicoils. Maybe they can ship to you?

https://www.olander.com/contact-us