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View Full Version : Awww Nuts, Striped a thread.



Black_Moons
07-08-2011, 07:57 PM
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
07-08-2011, 08:20 PM
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
07-08-2011, 09:16 PM
Ouch at $60 just for a M6 timesert kit... do look nice however..

PeteF
07-08-2011, 09:30 PM
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
07-08-2011, 09:38 PM
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
07-08-2011, 10:34 PM
Fill the hole with T.I.G welding and redrill and tap to M6.Problem solved.

tdmidget
07-08-2011, 10:38 PM
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
07-08-2011, 11:10 PM
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
07-08-2011, 11:58 PM
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
07-09-2011, 02:01 AM
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
07-09-2011, 02:15 AM
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
07-09-2011, 04:28 AM
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
07-09-2011, 06:59 AM
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
07-09-2011, 09:26 AM
Never saw one of these on a Boeing, where exactly are they used??


maybe the bit that sorta holds the motor on?

vpt
07-09-2011, 09:49 AM
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:

http://www.acmeindustrial.com/images/Keensert.gif


Time serts:

http://di110.shoppingshadow.com/images/di/39/52/4e/66336259555864735236676e30347251704641-149x149-0-0.jpg

Highpower
07-09-2011, 09:57 AM
Speaking of bits that hold the motor on....

I picked up this basket case chainsaw on fleabay that the owner had run to death with loose bolts holding it together. Mounting bosses were broken, split, wallowed out, stripped threads, etc.

Built up the bosses with tig, and re-drilled for helicoils. Bolts stay tight now so no complaints. But then again this is just a lousy $15.00 saw. <wink>

http://img.photobucket.com/albums/v82/Highpwr/Machining%20Projects/th_PC300011.jpg (http://smg.photobucket.com/albums/v82/Highpwr/Machining%20Projects/?action=view&current=PC300011.jpg) http://img.photobucket.com/albums/v82/Highpwr/Machining%20Projects/th_PC300012.jpg (http://smg.photobucket.com/albums/v82/Highpwr/Machining%20Projects/?action=view&current=PC300012.jpg) http://img.photobucket.com/albums/v82/Highpwr/Machining%20Projects/th_PC300014.jpg (http://smg.photobucket.com/albums/v82/Highpwr/Machining%20Projects/?action=view&current=PC300014.jpg) http://img.photobucket.com/albums/v82/Highpwr/Machining%20Projects/th_PC300015.jpg (http://smg.photobucket.com/albums/v82/Highpwr/Machining%20Projects/?action=view&current=PC300015.jpg)

lakeside53
07-09-2011, 10:13 AM
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


I've used these to repair a few busted 3/8-16. VERY NICE... Luckily I was able to borrow the setting tool and a inserts - they aren't cheap.

vpt
07-09-2011, 10:29 AM
I've used these to repair a few busted 3/8-16. VERY NICE... Luckily I was able to borrow the setting tool and a inserts - they aren't cheap.


Thats the ones I have not the time serts. I had to go look at pics of each to see which one was which again. So many different names for them, also called keenserts.

Black_Moons
07-09-2011, 03:50 PM
Keen sert looks nice.. Likey cheaper to use then the timesert.
Not sure im too keen at taping it out for M10.. but there might be enough metal there.. hmmmm.

Toolguy
07-09-2011, 04:02 PM
Keenserts work really well. I've used them for a lot of years. They have some advantages over other inserts. One is they use standard size and pitch taps. You don't have to buy a special tap for each size. Another is that you can easily drill out and replace them without damaging the hole they are in. They come in carbon and stainless, inch and metric, and specials. They have solid ones that you can drill and tap your own hole in the middle if a hole is off just a bit or if you need a special thread.

Black_Moons
07-09-2011, 04:07 PM
Keenserts work really well. I've used them for a lot of years. They have some advantages over other inserts. One is they use standard size and pitch taps. You don't have to buy a special tap for each size. Another is that you can easily drill out and replace them without damaging the hole they are in. They come in carbon and stainless, inch and metric, and specials. They have solid ones that you can drill and tap your own hole in the middle if a hole is off just a bit or if you need a special thread.

Really? they look kinda hard to drill out. Id assume those locking pins would be hardened steel and kinda rape the thread they lock into.

J. Randall
07-09-2011, 04:52 PM
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?

Beanbag, from the description it must be striped, like a Zebra.

form_change
07-09-2011, 05:16 PM
The 'setting tool' for the keyserts that I used was just a bit of bar with a shoulder on it. The smaller diameter was the minor diameter of the insert thread and the large diameter big enough to act as a punch on the keys. All the tool is doing is knocking the pins in straight rather than risking bending a pin by doing them free hand.
The ones I used most recently were 3/8 UNC, inserted into a 1/2 UNC hole in cast iron - worked like a charm. I had to buy a packet of 3, so if anyone needs 1 ...
The flyer link I posted has removal instructions.

Michael

Toolguy
07-09-2011, 05:23 PM
To drill out a Keensert, you use a drill just smaller than the ID of the locking pins. Once drilled, the pins (keys) are bent into the hole created and the insert unscrewed. The hole the insert was in just has 2 or 4 very small vertical lines in the side. Smaller inserts have 2 keys, larger ones have 4. The Keensert company provides all the information on tap and drill sizes.

lakeside53
07-09-2011, 10:58 PM
Keenserts (keyserts) can be hard to find. For those that can't find them, here's one source


http://www.allsafetysupplies.com/Keyserts.html

John Garner
07-11-2011, 02:59 PM
Black Moons --

EZ-Lok makes my first-choice thread repair insert. The insert is simply a threaded sleeve coated on the outside with an encapsulated adhesive. No special tools are needed, just a standard drill, standard tap, and a screwdriver or nut & bolt of the appropriate size and a wrench that fits. See the website for details: www.ezlok.com

Te-Co Products, the same Te-Co that makes standard jig and fixture components, is now offering what looks to be a clone of the EZ-Lok insert through their normal machine-shop-supplier distribution channels. Their website is www.te-co.com

Northwestern Tools, pretty much a direct competitor of Te-Co, makes a similar thread repair insert using a nylon-pellet locking device instead of the encapsulated adhesive. http://www.northwesterntools.com/-c-345_65.html

One thread repair insert that I haven't tried yet, but intend to, is from Groov-Pin. Their "Tap-Lok" inserts come in two flavors, Hole and Slot. Both are self-tapping into aluminum. http://www.groov-pin.com/new2010/threaded.php

And, of course, a homebrew solid-metal thread repair insert is pretty easy to make from a suitably-sized capscrew, and can be glued in place with an anaerobic thread-locking adhesive (what most of us mean when we speak the tradename Loctite) or filled epoxy (Devcon, Marine Tex, JB Weld, and others).

John

Black_Moons
07-11-2011, 03:05 PM
Black Moons --
And, of course, a homebrew solid-metal thread repair insert is pretty easy to make from a suitably-sized capscrew, and can be glued in place with an anaerobic thread-locking adhesive (what most of us mean when we speak the tradename Loctite) or filled epoxy (Devcon, Marine Tex, JB Weld, and others).

John

Hmmm Capscrews you say? I was thinking some threaded rod.. Not that I have any M10 threaded rod handy.. Loctite is a good idea to retain it...

Do I really need a retainer or is it only for conviance? Id assume a threaded insert would stay in a blind hole just fine under normal operation/vibration, Might come off with your bolt now and then when you remove the bolt, but id assume it would be easy enough to screw off and put back into its hole..

Why a cap screw? Or is that just for preventing it going too deep (requiring counterboring the hole)

John Garner
07-11-2011, 05:00 PM
Black Moons --

My experiences with homebrew thread repair inserts have mostly been exercises in Improvisation Engineering, and have usually involved both Midnight Oil and What's On Hand.

Sometimes the finished insert is reincarnated from a nut, sometimes from a bolt, and sometimes is found inside of a hunk of junk dug out of a scrap barrel or found alongside the road.

Sticking the insert in place is probably more of a convenience than a necessity, but I do generally either glue or pin 'em.

John

Black_Moons
07-14-2011, 05:07 PM
Grrr! Go to lordco to buy some inserts. They want to sell me a 5 pack at $4 per insert!! $20 for 5 inserts don't think so.

Go to allsafetysupplies.com. Put the inserts into my basket. $13. Not bad. Check out. Min order $15 required. Damnit. Add some low strength threadlocker iv been looking for everywhere. Get to checkout.

Shiping: 35.62
Domestic shiping: CAD 8.59 (Wut? Why is it being shiped twice!)
Grand total CAD 69.70 (+$17 if I prepay 'dutys and taxes' on it)

For $25 worth of stuff.. Grrrr. Totaly not worth it.

Any places in CANADA that sell keenserts for less then rape? Or should I just try and tap another M10 bolt again and see if I can get it straight this time...

Boostinjdm
07-14-2011, 05:46 PM
Grrr! Go to lordco to buy some inserts. They want to sell me a 5 pack at $4 per insert!! $20 for 5 inserts don't think so.

Go to allsafetysupplies.com. Put the inserts into my basket. $13. Not bad. Check out. Min order $15 required. Damnit. Add some low strength threadlocker iv been looking for everywhere. Get to checkout.

Shiping: 35.62
Domestic shiping: CAD 8.59 (Wut? Why is it being shiped twice!)
Grand total CAD 69.70 (+$17 if I prepay 'dutys and taxes' on it)

For $25 worth of stuff.. Grrrr. Totaly not worth it.

Any places in CANADA that sell keenserts for less then rape? Or should I just try and tap another M10 bolt again and see if I can get it straight this time...


$20 seems a whole lot cheaper than $69.70 + $17.:confused:
IF you've determined those inserts will give the desired results then buy the damn things and be done with it.

Black_Moons
07-14-2011, 05:49 PM
Actualy, Now that I think about it.. I'll likey just make my own. Too damn incovinant to buy at that price!

Do you think a grade 4.8 M10 bolt is good enough match for an aluminum cast engine to make an insert out of? the bolt that goes into it is grade 8.8 M6.

Can you even tap grade 8.8 bolts? the 4.8 was a little troublesome.

The engine has been known to snap cheap unrated chinese studs after going over enough railway crossings, Hence the upgraded grade 8.8 bolt that striped the motor threads insted of snaping. (Does that mean the typical cheapo chinese stud is weaker then cast aluminum?!?)

Mind you, my 4.8 grade bolt is from some cheap ass chinese bolt kit. So it might be made outta the same swiss cheese as the studs that snap. But at least it has a grade on it, So that must mean it at least meets some specs.. right?
And I would assume an insert would naturaly be stronger then the bolt inserted into it, Since its M10 outside threads are much bigger then the M6 bolts, and M6 inside threads are naturaly a little stronger then the outside threads they mate with, And being so short it can't really be bent.