Awww Nuts, Striped a thread.

[Black_Moons]

Nuts, Striped a M6 thread today in aluminum while puting my bike back togethor. Kinda critical too since it sorta holds the motor on.

Thankfuly this is in a large chunk of aluminum with lots of space around the thread... I... hope. I should really double check since there is a clutch bore close by, but I should at least be able to get 1/2" of M8 thread in, and if I drill into the clutch, its OK as long as I don't drill so deep as to damage it, its just grease filled.

Its about 1" deep, blind, though the bolt into it only engaged by about 1/2", theres another 1/4" of good thread at least before it tapers. Not really enough to be secure however with just a longer bolt, but im thinking a longer bolt should be used after repair, and for the other mounting hole?

I could in theory tap it out to be M8. I do have some high grade M8 threaded rod I could make a bolt outta. Space for the M8 bolt head + wrench might need some grinding but I think it should be doable.

Id rather use an insert however. Its the aluminum that failed, torn right out, down to about 80% of the root. Bolt thread looks fine. Happened while torqueing it to the same level I allways do, So I kinda suspect some of the thread had allready been damaged by stresses. (Going over bumps, chain falling off (Fixed), etc)

So, down to my questions. What are peoples feelings on verious inserts, Iv heard some people don't like the spring coil like inserts, but I don't recall anyone really saying why.
And would I be much better off taping it for M8 if I can?

[lakeside53]

I fix a zillion threads in mag alloys each year... And only use "Time Serts". Nothing beats these... and good enough for Boeing.

Helicoils in small sizes suck. IF you can get them in place, they will hold, but if you need to undo and replace the bolt good luck on it lasting.

http://www.timesert.com/

[Black_Moons]

Ouch at $60 just for a M6 timesert kit... do look nice however..

[PeteF]

Rather than going straight to M8, could you bodge it with a UNC bolt, 5/16? It may be able to be tapped straight out from what you have.

Just a thought.

Pete

[Black_Moons]

PeteF: Maybe.. however OCD is a pain in the ass. I also really like how the bracket/spacers involved can take any motor currently, where as drilling it all out might make it incompatable with unmodifyed motors.

[valimarsbro]

aluminum bolt hole stripped

Fill the hole with T.I.G welding and redrill and tap to M6.Problem solved.

[tdmidget]

I fix a zillion threads in mag alloys each year... And only use "Time Serts". Nothing beats these... and good enough for Boeing.

Helicoils in small sizes suck. IF you can get them in place, they will hold, but if you need to undo and replace the bolt good luck on it lasting.

http://www.timesert.com/

There's a hellavu lot of Honeywell in every Boeing and Helicoils are good enough for both of them. Note that the Timesert "locking mechanism" is incomplete thread at the bottom. This looks like a removal and destroy the thread system too.

[lakeside53]

The locking is performed by running an expansion tool down the insert. It pushes out the "incomplete thread", makes it "complete" and locks to the body. Once in, they never come out. I put these mainly in chainsaws. One pro guy had me replace every threaded hole with an insert (at rebuild time). If it was up to me, I'd just have done the recoil cover, muffler and carb studs.

Yes, $45-60 is a bit steep upfront, but once you are set up - I have 4,5 and 6mm (gulp)... iirc it's less than $1 per insert. You can get them in stainless, but I mostly use the steel.

[beanbag]

Pardon my ignorance, but what is an "awww" nut? I've heard of hex nuts, square nuts, lock nuts, etc, but never an awww nut. Maybe it's Canadian for something else? Is it one of those locking one time use only nuts that is designed to strip threads?

[Black_Moons]

Pardon my ignorance, but what is an "awww" nut? I've heard of hex nuts, square nuts, lock nuts, etc, but never an awww nut. Maybe it's Canadian for something else? Is it one of those locking one time use only nuts that is designed to strip threads?

Its a pun. 'Awww nuts' is something you say when you mess up.

[Boostinjdm]

Fill the hole with T.I.G welding and redrill and tap to M6.Problem solved.

I'd like to see you get to the bottom of the hole without turning half the case into a molten blob. He said M6, not M60....

Heli-coils work for me.

[form_change]

At work we use several things as inserts in Al, including helicoils.
Another type is a 'Keysert'

http://mdmetric.com/pdf/keysert.pdf

For an M6 you would have to tap M10 then wind in the insert, knock the keys in and you are set.

Michael

[luthor]

I fix a zillion threads in mag alloys each year... And only use "Time Serts". Nothing beats these... and good enough for Boeing.

Helicoils in small sizes suck. IF you can get them in place, they will hold, but if you need to undo and replace the bolt good luck on it lasting.

http://www.timesert.com/

Never saw one of these on a Boeing, where exactly are they used??

[Mcgyver]

Never saw one of these on a Boeing, where exactly are they used??

maybe the bit that sorta holds the motor on?

[vpt]

I love time serts! I received over $1000 worth of time serts from my father in law. Used a couple for my brothers motor for the head bolts and trans bolts. Nothing beats them!


Edit* I have the keenserts/keysert not time serts.

Because pics are needed, these are keen/key serts:




Time serts: