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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Posted: Aug 8, 2011 at 15:35 Quote
You are spot on! It's a SC Superlight with an integrated hanger. Thanks for the suggestions. You didn't mention drinking 6 beers and then running over it with my truck however...
As for the threads - pretty much completely wasted. Any solution will involve creating new threads...

Thanks again,
Andrew.

Posted: Aug 8, 2011 at 21:10 Quote

Yes I am ordering one of those as a backup plan but I know that some day down the road that damn thing will get lost and put me back at square one.... lol. Thank you kindly for the reference. I had heard of these 'dropout savers' before and I will likely end up going this way if I can't do a HC more cheaply or none of my Macguiver fixes work... Thanks again!

Posted: Aug 9, 2011 at 0:50 Quote
I agree with knobzy completely, which is what I was saying, those are exactly what I use on the Santacruz range, when you fit it into the frame use some kind of sealant to stop it from falling out, or buy a spare incae you lose it.

I use a compound sealant on jobs like that, loose bearings, any time I need to keep something in place.

Posted: Aug 9, 2011 at 21:44 Quote
........I managed to get new threads chased with JB Weld and it seems to be holding strong. Success!

A few tips I found after having poor results the first time....

Don't bother retapping the threads as the JB doesn't seem to like that too much (drilling seems fine but tapping a little sketchy). What I found is that if you thread a screw through the backside of the hanger while the JB is still wet, this will give a great thread pattern that will even work with a messed up bolt so beware as it will duplicate screwed up male threads this way.

I found that drizzling triflow on the screw was a great mold release and none of the wet epoxy stuck to it (this seemed to work even better than Permatex's own mold release agent included with the first (ahem) kit. As stated above, Permatex makes a kit that is designed to do exactly this but the method I mentioned above appears to be much better. I did lightly chase it with a 10x1 tap after a day of cure time but I'me not sure it was 100% needed. Get a longer bolt and thread it right through when the epoxy is wet (this pushes all the excess out). Using a longer bolt first and then immediately using the actual mech bolt made the difference between a good and a great repair.

Thanks for all the help! I have one of those inserts at the shop to pick up anyway as there's no telling how temporary this fix may be. Either way, having a few of those inserts on hand will never hurt. Smile

A.

Posted: Aug 9, 2011 at 23:06 Quote
neex wrote:
........I managed to get new threads chased with JB Weld and it seems to be holding strong. Success!

A few tips I found after having poor results the first time....

Don't bother retapping the threads as the JB doesn't seem to like that too much (drilling seems fine but tapping a little sketchy). What I found is that if you thread a screw through the backside of the hanger while the JB is still wet, this will give a great thread pattern that will even work with a messed up bolt so beware as it will duplicate screwed up male threads this way.

I found that drizzling triflow on the screw was a great mold release and none of the wet epoxy stuck to it (this seemed to work even better than Permatex's own mold release agent included with the first (ahem) kit. As stated above, Permatex makes a kit that is designed to do exactly this but the method I mentioned above appears to be much better. I did lightly chase it with a 10x1 tap after a day of cure time but I'me not sure it was 100% needed. Get a longer bolt and thread it right through when the epoxy is wet (this pushes all the excess out). Using a longer bolt first and then immediately using the actual mech bolt made the difference between a good and a great repair.

Thanks for all the help! I have one of those inserts at the shop to pick up anyway as there's no telling how temporary this fix may be. Either way, having a few of those inserts on hand will never hurt. Smile

A.

Cool, good to know your bikes rideable!

Posted: Sep 10, 2011 at 20:27 Quote
Ahem.... My son knocked my bike over the other day and the crack/bang/thud was enough to undo any success I had with epoxied threads. That said, I grabbed a beer and some cutting oil and went to work with a 1/2" bit (it is VERY tight on this frame as there's only maybe a 1/2" left before cracking out the mount hole. Anyway, I used one of those derailleur saver bolt things and it worked a charm. I used a little red rtv to make sure that it stays put if I pop the derailleur off or replace it. Thanks to everyone for all the help. Especially the 'buy two and stash one' suggestion which is exactly what I did. If I had to do this again I might just countersink the first few mm and recess a flat nut in there.... If it happens on a beater I am going to mig it to the frame.... heh...

Andrew.

Posted: Sep 11, 2011 at 3:38 Quote
Another vote for helicoil.

I've used them on renovation of bike engines and they've never let me down.

How deep is the hole that needs fixing?

Posted: Sep 11, 2011 at 5:28 Quote
Can you run a alu mech bolt hanger in the future ?

Posted: Sep 11, 2011 at 22:50 Quote
marquis wrote:
Can you run a alu mech bolt hanger in the future ?

If you mean replacing the bolt itself with aluminum - I'm pretty sure it is an aluminum bolt already. I think it was careless threading of a hanger straightening tool that put me in this boat to begin with. As I said though, it's all fixed now and works like a champ! Too bad that $0.04 gizmo costs $20.... heh.

:O

Posted: Sep 12, 2011 at 2:36 Quote
neex wrote:
marquis wrote:
Can you run a alu mech bolt hanger in the future ?

If you mean replacing the bolt itself with aluminum - I'm pretty sure it is an aluminum bolt already. I think it was careless threading of a hanger straightening tool that put me in this boat to begin with. As I said though, it's all fixed now and works like a champ! Too bad that $0.04 gizmo costs $20.... heh.

:O

Ah sweet,and ah my bad i wasn't aware it was alu already.

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