Crushed Campy dropout: How would you fix it?
https://cimg4.ibsrv.net/gimg/bikefor...15502b812.jpeg
I know how I would go about it but how you go about it? Just looking for a second, third or fourth option that may different from what I'd do. The owner and I both realize there's an exceptionally high probably of it snapping off. Chrome work looks like maybe its has cracks but no way to tell if the metal underneath is. |
1. Cheapest method: Bend back cold using a long piece of steel rod or square stock inside the dropout. It might crack, but if it works you're done.
2. Second cheapest method: Bend back hot using an OA or propane torch to heat up the bent portion and then bending back using the above method. Less likely to crack than cold, but you are looking at clean up and touch up, or rechrome/paint. I wouldn't worry about annealing because dropouts are not meant to be hardened anyway. 3. Third cheapest method: Use a torch to de-braze the dropout from the chainstay/seatstay and braze a new one in there. This is the least risky way to do it but is more involved and costs more. I personally would try #2 , and if that doesn't work, #3 . |
Originally Posted by miamijim
(Post 21183938)
https://cimg4.ibsrv.net/gimg/bikefor...15502b812.jpeg
I know how I would go about it but how you go about it? Just looking for a second, third or fourth option that may different from what I'd do. The owner and I both realize there's an exceptionally high probably of it snapping off. Chrome work looks like maybe its has cracks but no way to tell if the metal underneath is. I would consider tapping a cold chisel slowly in it to wedge it apart. As bad as it's closed, it may not survive. FWIW I think the packer/shipper should have done a much better job to prevent this, despite the extra cost, frames/bikes cannot be overpacked IMO https://cimg3.ibsrv.net/gimg/bikefor...e9f62ea547.jpg https://cimg8.ibsrv.net/gimg/bikefor...73a014ae69.jpg . |
Originally Posted by merziac
(Post 21183982)
FWIW I think the packer/shipper should have done a much better job to prevent this, despite the extra cost, frames/bikes cannot be overpacked IMO |
Originally Posted by miamijim
(Post 21183992)
I agree but at this point its too late.
|
Originally Posted by merziac
(Post 21183982)
The venerable @gugie addressed this before with the hanging end of a Cresent wrench on the hanger that provides good leverage.
. @TenGrainBread has the wisest advice. You could probably cold set it back, but thatsa lotta bend in a very small region. 8" Crescent wrench is typically my tool of choice to open/close horizontal dropouts when they need just a bit. Note: works for 7 o'clock (Campy style) dropouts - the wrench hanger hole catches on the derailleur stop, which is hidden in this picture. https://cimg2.ibsrv.net/gimg/bikefor...3a3831a430.jpg To open the hanger, a lot of tools would work, but an 8" Crescent handle is just about the right size and leverage. Note that the wrench I have above isn't a Crescent brand, but I've found that that the hole to hang the tool is about the same on all of them. |
What’s the over/under on it snapping off? 50/50
40/60 with 40 breaking? 60/40 with 60 breaking? |
Originally Posted by miamijim
(Post 21184084)
What’s the over/under on it snapping off? 50/50
40/60 with 40 breaking? 60/40 with 60 breaking? Also would be inclined to employ a heat gun, minimal higher heat, might appease some of the metallurgical gods on this. :rolleyes: |
Have had this happen but with the longer version, so the inclusive angle was slightly less.
A "Pro" painter did the poor packing job for me. I had sent him reusable box and packing that must have gone elsewhere... Grumble- especially as he commented it was the best packed frame he had ever received... Big Big flat screwdriver, inset parallel to how the axle would go, open it just a bit. back out adjuster. thread adjuster in from the back end till it terminated just short of the "slot". 3/8" fine thread bolt at U, with as stout of machined washers as you can find- tighten up- you want to keep the metal from bulging more. Some heat, not enough to burn the paint or chrome, but even 300 °F will help, slowly using that big flat screwdriver twist it in the opening to open it up. You want to walk up to the amount needed, not beyond. Take things apart and check flatness install wheel and check derailleur hangar. 50/50 the chrome will pop loose. |
Lower half of dropout in vise (with aluminum jaw inserts, of course), and use the frame VERY SLOWLY AND CAREFULLY as leverage.
If it breaks, it breaks. If it doesn't, you just dodged a bullet. Just hope it didn't form a stress crack at the adjuster. -Kurt |
Have been there. Use some heat. A little post touch-up paint is much less trouble than a full replacement dropout.
|
Curious - how is the RD?
Let’s say you get lucky and it doesn’t snap off. How concerned should one be about failure down the road? It has to be weakened, right? I would have no idea how to judge the extent. |
Originally Posted by due ruote
(Post 21184340)
Curious - how is the RD?
Let’s say you get lucky and it doesn’t snap off. How concerned should one be about failure down the road? It has to be weakened, right? I would have no idea how to judge the extent. |
1, Send me that rear derailleur
2, follow some the above instructions |
This dropout is forged steel. Pretty strong stuff and the grain structure will be helping in this case. My guess is that it will bend back. Heat might help. Of course, if it were my frame, my thinking would be to give it a try. I'd use heat and then touch up paint. If you ride the bike enough the color mismatch won't be so obvious.
The worst that could happen is that it breaks or cracks around the adjustment screw. If it does, then you will have to get a new dropout brazed in our forget about the frame. I don't think that would happen. I would also leave the screw in there when you are bending it. |
Originally Posted by Bianchigirll
(Post 21184375)
1, Send me that rear derailleur
2, follow some the above instructions |
Using very small directed flame to heat the back of drop out but not glowing hot, leaving adjusters in place... I would be incrementally squeezing the bulging sides of the dropout( protecting itfrom teeth) in the jaws of a big metalworking vise to original width, but leaving the dropouts in the vise as I worked, spreading the drop out open slowly. No matter which method I used to spread it, I would perform the two actions in conjunction.
I am a fan of tapping a fine tapering cold chisel or elelephant sized screwdriver into the mouth of the dropout. (Shaft of tool in line with chainstay.) Good Luck! Eric |
Originally Posted by merziac
(Post 21183982)
FWIW I think the packer/shipper should have done a much better job to prevent this, despite the extra cost, frames/bikes cannot be overpacked IMO
|
Originally Posted by shoota
(Post 21184442)
What’s so special about the rd?
|
Great advice and in-line with how I've done them in the past. This is being done 'remotely' but I think we'll get it worked out. Definitely will add heat to the mix. Back in the day I'd hook the dropout itself with the eye of a crescent wrench or big open end wrench but it doesn't look one will 'hook' in.
As far as packaging goes some of you know I wrote the book on it....I've since refined my methods and don't block dropouts. But that's for a different thread and a different day. |
I did one like this, an Italian bike, Paletti, Basso or something.
What I used was a rear axle threaded through the mounting hole, then another axle in the still-big end of the slot. Using two big adjustable wrenches (15" and 18" I think), I gripped both axles with each wrench, one to each side of the dropout. Then I was able to apply torque to force open the slot. I got nervous as I approached the needed slot opening width, so I stopped short of the full 10mm and went in with a file to the lower run of the dropout slot until an axle just passed all the way through the slot. That bike has moved on, but it seemed ok for some months while my friend still used it. I forget how it happened, but it wasn't from shipping. I think that he dropped it in his garage. |
After reshaping
I would the use the vise advice. Lots of steady leverage and easier to maintain alignment to the chain stays. The key to the safety side is remove wheel after first half dozen outings and check for cracks. If it fails catastrophically on the first serious ride the other side will hold the wheel on to allow you to come to a stop.
|
Originally Posted by gugie
(Post 21184077)
You could probably cold set it back, but thatsa lotta bend in a very small region.
|
Originally Posted by NoControl
(Post 21185014)
Not to mention that chance of success is low due to the adjustment screw hole being there. If this were my bike, I'd try the cold method first, but very slowly and very little movement at one time. Hey, it might work, right? If it don't then I'd find a framebuilder. This situation really puts the suck into an otherwise nice frame. So sorry!
Just an observation, YMMV. -Kurt |
Is it forged or is it microfusion? I can't tell from here. Old long ones as in gugie's photo are never a problem. Some of the real old ones are not even forged, they're just chromoly and you can do anything to them. Microfusion is gonna crack. Try it and see. If it cracks it was gonna crack and no subtleties of technique would have made the least difference.
|
All times are GMT -6. The time now is 10:15 AM. |
Copyright © 2024 MH Sub I, LLC dba Internet Brands. All rights reserved. Use of this site indicates your consent to the Terms of Use.