Hi All:

I need to have some driveshaft adaptors made to mate my Sierra diff to my MX-5 driveshafts. I'm considering having it turned up in 6061-T6 aluminum and using Heli-Coil inserts to attache the adaptor to the diff 'ear' (CV type).

Does anyone have any experience with the Heli-Coils? I'm wondering if they will be strong enough for this application. There are quite a few bolts in the Sierra diff 'ears', so it should spread the load out a bit...I've also noticed that the Race Leda uprights use the Heli-Coils. But again, I just want to make sure this will be safe!!

--Many thanks, Chris

In my experience, heli coils are usually stronger than the material that they are being inserted into, just make sure you use the correct tapping drill diameter and dont go larger!!
cheers colin

We use helicoils on practically all aluminium engine and undercarriage parts at work. Loads stronger than just tapping into the ally and bolting straight in. They're great.

Liam

ditto Liams comments........

the lynx helicopter uses 16 helicoil inserts for the bolts that hold the main rotor head to the gearbox! if they are strong enough for that then they are strong enough for me!!!!

Thanks for all the help gents! That was just the warm fuzzy I needed. Looks like I'll order a couple sets.

--Chris

another option to look for is time serts, we used these in the touring cars on all alloy suspension they are a full sleeved with a thread and are less likely to pickup and try to come uncoiled like helicoils when removing the bolt ( although not that common a problem admittedly )

I have 4 heli-coils holding both my rear calipers on my Xantia. Still holding strong.

P.S. What a b*****d of a job that was

for once all of the advice above is spot on and I can't argue with it!!

Note Marc Norden's comment, re. convenience of disassembly. helicoils can pick up and that makes them a pain when undoing. Still plenty strong though.

I put loads of helicoils in Lotus Twincam heads --- as everybody says no problem just watch they can unscrew when stripping down which isn't difficult to deal with -