Screw lockers 2

[PK69]

I saw that in the thread24-131607 Timelord suggest Helicoil as screw locker. For space application is there any standard? Could you suggest company for space qualified helicoil?
Thanks,

emilio

 

[btrueblood]

We always were forced by old spacecraft company spec's. to use lockwire for all fasteners. Nylon patch type threadlockers were not suitable due to high launch vibration (i.e. they didn't hold), Locktite adhesives were banned due to outgassing, and thread-deformation types were banned due to lack of re-usability, and fear that burrs raised in assembly could come adrift in space and cause all sorts of problems. YMMV, what does the vehicle spec./design standard call out?

 

[btrueblood]

Oh, and the reason we couldn't use heli-coil inserts was the fear that broken-off drive tangs could be floating around inside the s/c. The s/c manufacturer didn't want to go thru the hassle of tracking each insert and recovering the tangs (this is the method used by a second mfgr. we worked with). The "new" tangless inserts should alleviate that problem.

 

[PK69]

Thanks for your answer. Actually we are still open to different solutions. Main ontraints are the max temperature reachable (290 °C), compatibility with our propellant (so probably solithane or Nytemp are not aplicable) and dimensions M2 and M3. So the best solution could be helicoil (screw lock type). Is there a NASA std applicable for helicoil (or is it sufficient demontrate that were space-qualified in another mission)?
Cheers