Stripped derailleur mount hole (bonded to frame - alu) - any creative approaches? thinking of filling with alu rod...

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Stripped derailleur mount hole (bonded to frame - alu) - any creative approaches? thinking of filling with alu rod...
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flag neex
Posted: Aug 6, 2011 at 16:19 Quote
I have made it for over 20a without this happening but it finally happened and I have a stripped bonded aluminum derailleur bolt/mount hole. I attempted to clean the threads on both the bolt and the hole with a 10x1 tap/die combo but the threads in the hole are too shallow. Is it possible to source an oversized (say 11x1.0) derailleur hanger bolt with recess for c clip, etc?? Also, I am looking at either a helicoil/timesert option but it's pricey even if I do it myself. I know that there's a solution out there by Problem Solvers that uses an internal sleeved thread drilled the next size up (5/16 maybe?). Now, the real meat of the question I have is whether or not it would work to use a low temp alu filler rod with my OA torch or a propane/MAP torch? I am wondering if heating the hanger will compromise the heat treating in the chainstays, etc? can I wrap a wet cloth around the stays to isolate them or am I dreaming? I also thought about using something like JB Weld to chase the threads and retap but I am open to all ideas. This is not a hanger but it actually integrated and dumping the frame is not an option.

Thanks for any experience-based help any of you who have been down this road before can suggest.

Andrew.
flag DH-hero
Posted: Aug 6, 2011 at 17:01 Quote
i had the same problem on an old manituo frame fixed it with a helicoil worked out great
flag knobzy
O+
Posted: Aug 6, 2011 at 20:32 Quote
helicoil isn't pricey.

Hit up Lordco. Shouldn't be a ton of money.
flag neex
Posted: Aug 6, 2011 at 20:41 Quote
Thanks! Lordco is a supplier I assume? I found some shyte manuf by Permatex that sounds promising. It's an epoxy thread repair that holds up to 120lbft and is used in auto/marine pretty regularly. I almost brazed it with a 750d alu rod tonight but decided to hold off as I was nervous about screwing up the temper. I heard that Helicoils use a proprietary tap - is that true or BS? I have a zillion taps and found that kind of tricky to believe.

When you Helicoiled your bike, did you need to trim the back side flush??
Thanks again!

A.
flag knobzy
O+
Posted: Aug 6, 2011 at 20:47 Quote
neex wrote:
Thanks! Lordco is a supplier I assume? I found some shyte manuf by Permatex that sounds promising. It's an epoxy thread repair that holds up to 120lbft and is used in auto/marine pretty regularly. I almost brazed it with a 750d alu rod tonight but decided to hold off as I was nervous about screwing up the temper. I heard that Helicoils use a proprietary tap - is that true or BS? I have a zillion taps and found that kind of tricky to believe.

When you Helicoiled your bike, did you need to trim the back side flush??
Thanks again!

A.

lodrco is a auto parts store. never heard of it?
flag neex
Posted: Aug 6, 2011 at 20:59 Quote
I think they're strictly on the W coast. I found their website - thanks. As for the Helicoil in a 10x1.0mm, I can't find any listed at my local industrial place (www.grainger.ca). They have every other damn size you could possibly imagine but nothing in a 10x1. Do you have a part number of the insert you used by chance? Sorry - got it -->
CWHC-R474-4 $7 PER PACK OF 6 SIZE 10 x 1.0MM 1/2" REACH REPLACEMENT THREAD INSERT

Is it possible to get this put it without the breakoff tool, etc? I was hoping to drill it and then thread it in with a gizmo of an appropriate size in my shop (I was thinking maybe a punch or something).

Thanks again!
A.
flag knightridersix04
Posted: Aug 6, 2011 at 23:01 Quote
I just took a drill to the opposite side of the mounting bolt, took it out in about 2 seconds or less
flag neex
Posted: Aug 7, 2011 at 15:01 Quote
knightridersix04 wrote:
I just took a drill to the opposite side of the mounting bolt, took it out in about 2 seconds or less

Can you explain this in a little more detal kingridersix04?? I think you misunderstood the situation - I have no issue removing the bolt - the threads are stripped and it will not hold the rear mech in place. I have since tried the Permatex thread repair kit and although I think it would work well in some scenarios, I don't think it has enough body to repair completely stripped threads. I am going to try a stronger epoxy like JB and then I'm going the helicoil/dropout saver route. I am also halfway considering 'building' a threaded insert. If it works, I will post up.

Thanks,
Andrew.
flag knightridersix04
Posted: Aug 7, 2011 at 15:02 Quote
you're trying to get the derailleur off the hangar right?
flag neex
Posted: Aug 7, 2011 at 15:03 Quote
knightridersix04 wrote:
you're trying to get the derailleur off the hangar right?

No sir. This frame has an integrated mount (i.e. no hanger). The drilled 10x1mm thread is stripped and needs to be repaired so here we are....

Thanks,
Andrew.
flag knightridersix04
Posted: Aug 7, 2011 at 15:04 Quote
nevermind, thought it was a different situation
flag neex
Posted: Aug 7, 2011 at 22:39 Quote
knightridersix04 wrote:
nevermind, thought it was a different situation

I wish it was... We'll see how this epoxy machined thread holds... ahem...
flag lafalot
Posted: Aug 7, 2011 at 22:53 Quote
if you don't want to use threaded inserts, here are some options:

1. coat threads in lots of permanent (red) thread lock and let it dry for a day after tightning as much as it will allow, may not work if threads are too wasted

2. epoxy/jb weld a m10 nut onto the stripped frame. you will either need to take out a spacer on the hub or change derailleur chain alignment to since this m10 nut is usually pretty thick.

3. similar to 1. just jb weld the shit out of the thing and put er in there. its obviously going to be a bitch to remove if you snap the bolt, but it'll hold strong until then
flag kaesae
Posted: Aug 8, 2011 at 0:45 Quote
What kind of frame is it and are you saying that you have a frame with a mech hanger that isn't replaceable and is permanently attached to the frame.

Like you would find on an older santa cruz frame etc

If that's the case the brop out saver / thread saver is your best option.

The design means that it will be held in place by tightening up the threads, I've used these on Santa cruz frames and older intense ones as well, when the mech hanger threads have stripped and I haven't been able to siply replace the mech hanger.

Then again you might not be talking about that at all Madder
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