Helicoils

[Gwil]

alloy and stainless, isnt that a no no due to galvanic corrosion?
https://www.albanycountyfasteners.com/blog/2017/09/15/stainless-steel-and-aluminum/

No, or, yes, depending on how you do it! Dipping the bolt in zinc chromate paste will enable the bolt to still be removed- in a marine environment- years later. Do the same with monel rivets. If the fastening schedule for the bolts/washers etc. allows it then by all means add insulating washers as well.

Without such treatment the combination is deadly even in the relatively short term.

 

[bricol]

Woodbery Chilcot used to have a test alloy plate on the counter with hellicoils in it think 3/8 & 5/16 & a box of standard bolts if you were bored waiting you could snap of a couple just to prove how good they were.
We used to fit them as standard to any alloy bits on the rally\ race\hill climbeView attachment 157111 cars gear boxes bell housings diffs etc.

We used to fit them in everything ali on new million quid machines . . . then did a test with 12.9 cap head direct into tapped holes - snapped the bolts before stripping the threads.

So now we only fit them to stuff that is continually being changed due to product size changes - they don't wear as fast, and if they do, take 'em out and fit some new ones.

 

[Jlg]

We used to fit them in everything ali on new million quid machines . . . then did a test with 12.9 cap head direct into tapped holes - snapped the bolts before stripping the threads.

So now we only fit them to stuff that is continually being changed due to product size changes - they don't wear as fast, and if they do, take 'em out and fit some new ones.

How do you take them out

 

[Seadog]

File a notch with a triangular file. Then use a triangular scrapper, located in the notch, to wind it out.

 

[Seadog]

If you don't happen to have a triangular file/scraper to hand then you can also pick out the start of the coil with a scriber or similar, grip it with needle-nosed pliers, and then unscrew it. I've used both methods successfully.

 

[slim_boy_fat]

If you don't happen to have a triangular file/scraper to hand then you can also pick out the start of the coil with a scriber or similar, grip it with needle-nosed pliers, and then unscrew it. I've used both methods successfully.

Probably a better way when faced with a h/coil in a blind hole?