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Headtube crack

Old 04-21-18, 09:41 PM
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Headtube crack

Hello,

Just gathering all the information I can. What do you think the options are for this crack? Mid 90's Bianchi TSX frame. The crack does go through the tube. I'm thinking probably the best thing to do is replace the headtube? is it? I do have a raw NOS Columbus headtube, same steel - cyclex. If you replace the headtube, do you need to replace the lugs? Or... is it possible to braze it, fillet braze the area (is that possible? over the lug), or..do people epoxy frame cracks ever? (wern't the vitus frames epoxied into the lugs?) It does seem the flex from the crack has tugged at the downtube bottom bracket joining (OS downtube) could be a little out of alignment, with possible crack between lug and frame in the brazing material.

Now, without knowing I did ride this bike for the better part of a year with the crack, and it never seemed to get worse. Though I did get another Bianchi TSX frame exactly the same in red, and when i rode that, it became apparent to me how much flex was in this frame, especially the BB. I also seemed to pull to the left a little despite the forks and bars being in alignment. The frame is stripped and hanging on a wall right now so it's not an urgent thing, and I don't want to spend hundreds paying someone to fix (I would rather spend the same hundreds buying the tools/ knowledge required) I 've already wrote it off, and basically now a project to see if I can fix it....someday...or, it looks pretty good on the wall....
Thanks
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Old 04-22-18, 03:17 PM
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There are a few ways this might be fixed, bonding isn't one of then that I would suggest.


As there's a good chance that the crack could be evidence of a poor/lack in/of brazing the lug and seems to extend through the lug (HT and DT surfaces) I think I would remove the lug and replace the HT and lug.


I'd start by stripping the area (including the top tube and lug area) of paint and blasting lightly to be a better view/understanding. If I still felt that the lug/DT socket was affected I'd check for any pins (drilling then out if present) in the DT socket and then pull the HT and lug off the DT then the TO lug (having cut the HT in half or taken a crossing slice out first). Even If I thought that the DT socket wasn't affected I still might replace it as a precaution. If the TT lug looked nice I'd consider grinding the HT out of it to reduce the heating cycles.


Of course I'd have somehow documented all the geometry, fitting the frame in a jig before beginning is the best way.


That this frame is likely brassed I'd try to reduce the heating cycles as can and if fit up clearances allow use silver to rejoin. Andy
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Old 04-22-18, 03:42 PM
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Pull out the fork and examine the inner surface of the head tube. If you can see the crack on the inside, the head tube will need to be replaced. If there's no crack on the inside, the crack on the outside is probably a brazing failure. Clean off the paint thoroughly (sand/media blasting preferred), and it may be salvageable by flowing fresh brass into the cracked area. Examine the inner surface of the head tube again afterward to see if fresh brass is visible, indicating a crack that wasn't previously visible. If you see a crack now, you'll need to replace the head tube.
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Old 04-22-18, 04:45 PM
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Originally Posted by JohnDThompson
Pull out the fork and examine the inner surface of the head tube. If you can see the crack on the inside, the head tube will need to be replaced. If there's no crack on the inside, the crack on the outside is probably a brazing failure. Clean off the paint thoroughly (sand/media blasting preferred), and it may be salvageable by flowing fresh brass into the cracked area. Examine the inner surface of the head tube again afterward to see if fresh brass is visible, indicating a crack that wasn't previously visible. If you see a crack now, you'll need to replace the head tube.
Ya, I did that, that was the moment I stopped riding the bike because the crack is visible on the inside.
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Old 04-22-18, 04:51 PM
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Originally Posted by Andrew R Stewart

I'd start by stripping the area (including the top tube and lug area) of paint and blasting lightly to be a better view/understanding. If I still felt that the lug/DT socket was affected I'd check for any pins (drilling then out if present) in the DT socket and then pull the HT and lug off the DT then the TO lug (having cut the HT in half or taken a crossing slice out first). Even If I thought that the DT socket wasn't affected I still might replace it as a precaution. If the TT lug looked nice I'd consider grinding the HT out of it to reduce the heating cycles.


Of course I'd have somehow documented all the geometry, fitting the frame in a jig before beginning is the best way.


That this frame is likely brassed I'd try to reduce the heating cycles as can and if fit up clearances allow use silver to rejoin. Andy
Thanks for all the info, I was thinking that would be the best course of action. What type/brand of torch do you recommend, that is reasonably priced ?(mid range).
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Old 04-22-18, 08:45 PM
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Repairing a frame isn't the place to start your brazing education. Do I need to repeat this? Andy
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Old 04-22-18, 09:01 PM
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If my second post seemed a bit cold and harsh it should.


The need to control the heat when pulling apart a frame, especially if brassed, is vital to the repair being a long term one. Tubing is designed to have one heat cycle, when it's initially joined. The pull apart is a second and the rejoining is the third. If the first was badly done (and the crack/lug separation from the HT/DT suggests such) then the repair has an even higher need for care.


Given the question about which torch is a good choice makes me think you have no experience in brazing. Is this correct? If so then I don't suggest you try this repair until you've done a fair amount of torch work and it's proven to be good work by time and miles.


Sorry to be the one to have a strong opinion. Just trying to have you avoid a weak frame after the repair. Andy
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Old 04-22-18, 10:22 PM
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I agree with Andrew but might add that beside you are talking about reheating the tubes several more times, it is super difficult to remove lugs from tubes. To get the heat spread out over a large enough area a rosebud (or two) may be necessary.
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Old 04-23-18, 03:40 AM
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it's not really that difficult to remove a head tube, have you done it?
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Old 04-23-18, 01:19 PM
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Originally Posted by Andrew R Stewart
If my second post seemed a bit cold and harsh it should.


The need to control the heat when pulling apart a frame, especially if brassed, is vital to the repair being a long term one. Tubing is designed to have one heat cycle, when it's initially joined. The pull apart is a second and the rejoining is the third. If the first was badly done (and the crack/lug separation from the HT/DT suggests such) then the repair has an even higher need for care.


Given the question about which torch is a good choice makes me think you have no experience in brazing. Is this correct? If so then I don't suggest you try this repair until you've done a fair amount of torch work and it's proven to be good work by time and miles.


Sorry to be the one to have a strong opinion. Just trying to have you avoid a weak frame after the repair. Andy
Oh I fully agree! I would not attempt anything before I thought I had the necessary skills. There is a frame building course I've been strongly considering taking here in BC (taught by Paul Brodie), if not that, I plan on learning at some point. It's a long term project, I would hate to needlessly destroy a beautiful frame...and would be rewarding be able fix it one day. I appreciate all the cautionary info just the same! point well taken. Thanks!
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Old 04-23-18, 01:44 PM
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Originally Posted by unterhausen
it's not really that difficult to remove a head tube, have you done it?

I was wondering if you feel that it is so easy to replace a headtube, that you chime in and give your method, at least for me, I found it to be just about impossible with the top and downtubes coming in at different angles and trying to heat up the lugs and get all of the brass molten/ soft enough to pull a tube/ headtube out. I mean I have "built" hundreds of frames and two dozen tandems, but don't have really ability to pull tubes out from lugs. I admit that my skill set is lousy. The last time that I attempted it I wound a chain around the frame and screwed the chain to a table and then attempted to twist the tube out as I attempted to heat the lug. No luck
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Old 04-23-18, 02:30 PM
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I am just sayin' that I would not advise a guy with no brazing experience and to expect him to be able to easily replace a headtube. I mean really if some guy who has extensive brazing experience (me) is complaining, you would honestly advise this guy to go for it???
Not sure that spending hundreds/ maybe thousands to travel and take a framebuilding corse to save what is termed as a "beautiful" frame I mean it really looks like the lowest of low end bianchis to me. I would say my last rights, conduct a burial and say good bye, if it were mine.
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Old 04-23-18, 04:02 PM
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Sorry, I'm really tired from riding my bike for too long. The way I did it was to cut away most of the head tube that's not inside the lug. Then slit the remaining tube. It's easier if you do that in a couple of places. It's relatively easy to locally heat the head tube enough to get it to lift off of the lug. Just heat from the inside, and only the lug and filler really get hot. Peel it off with some pliers. As always, patience is rewarded. If the lug starts getting red, let it cool down.

I have only done this once, and I'm not convinced I would do it again. The reason being, the frame I worked on was not mitered properly, so it's still not mitered properly. It was beautiful though, had Dupont paint that changed from purple to green depending on the light, and the lugs were beautifully thinned. I suspect that the head tube was filed a little too much around the lug, there was a lug-shaped crack around 99 percent of the shoreline. But the work of replacing the tube was super easy.
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Old 04-23-18, 09:40 PM
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The alternative to heat to pull a tube is to grind it away. If the socket is a through hole and not blind this can work well with not too much skill needed (but a lot of care and time), One trick it to watch the surface that's being ground and when it turns color the tube is gone and the filler is the layer you see. Easier said then done as it's easy to go too deep/far in some sections and less on others right next door. This takes time (did I say that already...) The head tube passes through the lug as a through hole.


The lug surrounding the DT is completely exposed to a mechanical removal. Again care as to how much removal is needed. Again very slow.


This pace is why one usually hears of the heat pulling methods, they are significantly faster. Eric's mention of parceling out the portions of a tube's removal with heat is a good one. leaving enough of the HT to grab with a pliers to do a "sardine can coiling up" technique is one I've been told of before. I supplied a length of HT for a friend who did the removal this way a couple of years ago. As he said the trick is the heat level and concentration so the HT is able to be soft enough to curl up around the pliers but not distort/damage the lug. Again easier said then done.


I have not done this myself. The tubes I've removed have either been in total with a lot of heat or with the relatively cool temp of grinding. This is something I should try on a junked frame sometime. Andy
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Old 04-24-18, 09:52 PM
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Originally Posted by skillasw
Hello,

Just gathering all the information I can. What do you think the options are for this crack? Mid 90's Bianchi TSX frame. The crack does go through the tube. I'm thinking probably the best thing to do is replace the headtube? is it? I do have a raw NOS Columbus headtube, same steel - cyclex. If you replace the headtube, do you need to replace the lugs? Or... is it possible to braze it, fillet braze the area (is that possible? over the lug), or..do people epoxy frame cracks ever? (wern't the vitus frames epoxied into the lugs?) It does seem the flex from the crack has tugged at the downtube bottom bracket joining (OS downtube) could be a little out of alignment, with possible crack between lug and frame in the brazing material.

Now, without knowing I did ride this bike for the better part of a year with the crack, and it never seemed to get worse. Though I did get another Bianchi TSX frame exactly the same in red, and when i rode that, it became apparent to me how much flex was in this frame, especially the BB. I also seemed to pull to the left a little despite the forks and bars being in alignment. The frame is stripped and hanging on a wall right now so it's not an urgent thing, and I don't want to spend hundreds paying someone to fix (I would rather spend the same hundreds buying the tools/ knowledge required) I 've already wrote it off, and basically now a project to see if I can fix it....someday...or, it looks pretty good on the wall....
Thanks
I do not know how attached you are to the frame or even what size it is, but another option is that I spotted a really awesome mid 70's Windsor road bike with chrome lugs and mid range parts on craigslist Phoenix for $180.
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Old 04-25-18, 09:55 AM
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it's hard to get a frame repainted for that kind of money. That's why I rarely repair frames for myself. The only justification I can see for it is sentimental value, and I just have trouble getting sentimental about bikes, there's always another one
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Old 04-25-18, 10:11 AM
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Originally Posted by Brian25
I am just sayin' that I would not advise a guy with no brazing experience and to expect him to be able to easily replace a headtube. I mean really if some guy who has extensive brazing experience (me) is complaining, you would honestly advise this guy to go for it???
Not sure that spending hundreds/ maybe thousands to travel and take a framebuilding corse to save what is termed as a "beautiful" frame I mean it really looks like the lowest of low end bianchis to me. I would say my last rights, conduct a burial and say good bye, if it were mine.
The Bianchi TSX is a far cry from the lowest of the low end Bianchi frames!

Anyways like I said, just fishing for information....so info on how difficult it may be is appreciated all the same, and it might not be worth it, and (most likely) never happen, if it did, it would be a rewarding accomplishment.
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Old 04-26-18, 01:57 PM
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