Odd fork problem discovered!
 

I've been disassembling a pair of bikes belonging to a friend. He and his wife bought them 50 years ago when they were married, and asked me if I could try to do some refurbishing. They asked me if the frames need painting, and I said "yes, there's a lot of rust!" So the job has grown to full teardowns. On the His the only major issue was a stuck stem, which yielded to a soaking in Super Duper Strength Liquid Wrench. Same issue appeared on the Hers. After a day of SDSLW I gave the bars a twist with the wheel between my legs and it moved! I started turning back and forth with a little lift, and the stem was not moving, rather the steer tube was coming out of the fork crown! I stopped before I had a shower of bearing balls, but ... Other than to tell my bud, what next?

I know frame builders braze or weld steerers into fork crowns but can a joint like this be re-brazed? I guess I'm worried about effects of repeated heating. The target site for painting is also a frame builder so at least the right skills are accessible.

Any ideas?

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tip -

twisting with the wheel held between the knees is a poor idea

a spoked bicycle wheel has an excellent strength to weight ratio with vertical loads...

...not so much with side loads

if this comes up again the best technique is to remove the wheel and brake caliper and then lock up the crown in a beefy bench vise with some blocks of soft wood for cushioning

then you will have both hands free for twisting and neither the fork nor the wheel will be at risk

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If it wasn't severely overheated originally which seems unlikely since it let go and the repair is done by an expert, it should be fine. ;)

The surfaces now have to be prepared with abrasives and with flux before re-brazing can be done, so you have to get the parts completely separated first.

I'm not sure if the order of operations now will be optimum, since the fork blades are now brazed in. But a framebuilder can fixture everything to allow the steerer to be brazed in. Paint around the crown will of course will be gone when all is done, so probably easier to find a replacement fork at this point.

The steerer should still be strong after the repair.

This is a ~1973 Raleigh, right?

I've replaced steerers on a few forks. It's a pain in the rear, and the next time I do it the cost will be twice what I've done in the past! I don't heat up the fork crown to remove it, as doing so might (probably?) detach the fork blades as well. It's cut, drill, and file, all by hand. New steerer gets silver brazed in, almost all vintage production bikes have fork blades that are bronze brazed, which melts at a signficantly higher temperature than silver based rod, avoiding the fork blade issue. I wouldn't reuse the old steerer, cost of a new one is insignficant compared to the labor cost.

This means that fork better be something special, otherwise you're better off just getting a new replacement fork.

No, it is about 1973, but it is a Witcomb USA. They had a higher-end bike, full Reynolds db531 with Campy fork ends and dropouts, and they had a mass-produced one made of 531 plain gauge throughout, stamped dropouts and fork ends. While the BBs are cotterpin, I don't think they are the Raleigh threading. I should check that by trying to thread in a BSA cartridge BB. These bikes are the lower-end frame and fork.

As far as order of operations, we've been planning to send them out for painting. I think we'll still do that and see what the paint/frame shop says. I've alerted my friend he might end up having a new fork built and some common prices for that, but he is not too concerned.

Well, this one will not need heating to remove! The crown with legs attached is trying to fall off of the steerer tube! I managed to stop it from causing a shower of headset bearing balls! I was only trying to get the stem to come loose from the steer tube!

If the fork blades are brass-brazed, you could reattach the steerer with silver braze, right? Or would the thermal mass of the crown plus blades make sure the crown got super hot?

OP's like, "you wouldn't like me when I free a stuck stem."

https://i.imgur.com/mqFfglF.jpg
.

Yes, and no (unless the person doing it does not know what they are doing). Knowing which part of the flame is the hottest, and estimating how much heat (not the same thing) it can transfer, and watching the gas flow can allow one to be precise enough to hold that difference in temperature across that distance. It's the same as what makes using a torch to get a cotter pin out so simple, you just make sure the crank gets hotter than the pin.

Having a steerer come out of the crown is just amazingly inept framebuilding. It should literally be impossible (and I don't use 'literally' to mean 'figuratively' like the kids do these days). Unless the original hack who made it was a poorly-trained idiot on drugs, the steerer-to-crown bond is way stronger than either the steerer or the crown. So if you tried pulling it apart with massive hydraulics or whatever it takes, the steerer or crown would fail before the braze did. And that bond doesn't have a "shelf life", it can't be worn out from riding. Many forks made in the 1870s are still safely connected there, so this being from the 1970s is no excuse.

BTW I'm pretty sure what your friends bought weren't really Witcombs. The ones that came with cottered cranks, though sold under the Witcomb name, were not made by them. Richard Sachs who worked for Witcomb back then had this to say: "these are the POS Witcomb USA branded bicycles made in a factory in Pwllheli, Wales."

He went on:
"The factory never made bicycles before these. And after three containers worth I doubt they continued. There was no rhyme or reason to the placement of brake bridges and chain stay lengths. These gaffes affected brake, tire and chain ring clearances. Many head tubes weren't faced, and the tubes showed through the lugs by a millimeter or so."
"At least an entire container of bicycles came (assembled, and boxed) on which the seat lugs weren't slotted for the binder bolts."
:wtf: [the smiley is my comment, not part of the Richard Sachs quote.]
So, with a fork that ineptly made, I'm pretty sure I would never trust it even if someone good brazed in the steerer. I wouldn't ride the "His" either, since its steerer may be one ride away from popping out. How would you know? (Before it happens that is. After it pops out, you'll know!)

These are just bad bikes that should never have been made, and fixing them will cost more than buying some actually good vintage bikes. I can see over-paying to fix them if the sentimental value trumps rationality, but your friends should be told that these will never be good bikes. They should be considered BSOs (bike-shaped objects).

Any chance of getting photos of the crown and steerer? Preferably with them apart, though I realize that may be difficult. Good, focused close-ups will be a minimum requirement to get a meaningful repair estimate from the framebuilders on the list. I myself am a retired ex-framebuilder who's gradually gearing up to make them again on a hobby basis, but I won't be bidding on this job. I only want to see photos because I'm curious, and I have a collection of pictures of really bad bike frame workmanship that I've collected over the years.

Mark B in Seattle

Mark, thanks a lot for your input! I've also spoken to Richard about these, and he shared his opinions. They might be Witcombs simply because of original labelling, but I get your point. I expected something like a Mercian or Woodrup, and I see something different. And working with these frames in the wake of working with my Super Course, '52 Rudge Aero Special, and (on the other side of the coin) my '80s Mondonico ... yes I see the difference! I've never previously had a fork in my hands which did not feel solid. And in previous cases of stuck forks I have cranked pretty hard on the 'bars while holding the wheel, (one of our colleagues has already chided me in this thread that wheels are not made for this stress) the forks have always felt as solid as a rock, so I can appreciate the uniqueness of this problem and the rider risk. Still, they have carried their riders for 50 years.

I confess when I first tried to remove the cockpit on the Hers I gave it a mighty heave, and the fork blades are now more out of alignment than before. When I attached my "mule" wheel yesterday and the motion began, it was a struggle to mate the wheel to the dropouts. But I have nowhere near the kind of strength it would take to have created the loose head tube. I think the crown would not have twisted as it did if the steerer was properly attached.

I can also appreciate how a pinned construction could have provided a redundant connection, but that does not demonstrate it is needed, because I'd guess way fewer than 1% of even handmade frames are pinned, and it sounds like a broken of missing braze is just extremely rare. My Mondonico is noticably pinned in the BB but not in the fork crown, and my '60s Rossignoli was pinned in the BB and in the fork.

Today I need to turn the frame fork so I don't have 50-something ratty BBs on my floor and getting stepped on my my old bare feet. After that I should be able to share some pics. For comparison you can look at the His as well as the Hers.

oh man, I can only dream! I'm much more couch potato than even Bill, absolutely light years away from Ferrigno!

Yes, it could, in principle at least. Re-heating isn't likely an issue; that it came apart so easily suggests it never got hot enough in the first place. But it would require thorough cleaning and repainting afterward. Unless it's a high-end frame, it's probably more cost-effective to replace the fork. Chrome plated replacement forks look decent, are reasonable priced and available. Be sure to get an appropriate steer tube length. Match the wheel size (be sure the brakes will reach), and get close to the original fork rake to maintain consistent handling.

The plan for painting these frames is and has been to give the job to a frame shop that has full painting, alignment, frame repair, and frame building capability. We found one and while we need to check on the exact mechanics, I think we have the right resource. I still need to loosen the stem from the head tube in order to pull out the headset cups. So we'll see how hard that all turns out to be.

There is no way I will be brazing the crown back onto the steer tube. While I have some engineering background I don't know the manual arts and crafts necessary, nor even how to light a torch much less use it without burning down the house.

Sorry, y'all for no pics, but after wiping down the joints I see just a little bit of brass around the bottom of the steer tube, and none at the top. My guess is the braze never penetrated into the whole steerer-crown joint. I'd assume you feed the rod in one side and see it seeping out on the other side, thus verifying penetration.

as the steerer is already loose as described, inspection of the two parts might just reveal that the fork was tack brazed at best.
I have seen a few forks where the flux was the structural component, and the brake pivot bolt!
chean, flux set in position, possibly with a pin to keep the holes aligned and braze it in.
to be ultimately careful, a new steerer.
I think trashing the paint is a good idea to visually assess the blade brazing.

the path of least resistance might just be a chrome replacement fork.

these are probably cheap Irish bikes anyway

That's interesting they brazed from the bottom. I guess i do that now too, but checking for filler coming out the top seems like a the minimum owed to a customer.

I assume you took the brake off first? Put a 6mm bolt in there assuming you haven't gotten the stem out yet.


Remelt temperature is enough higher than the melting temperature of the same filler that I wouldn't have any qualms about brazing the steerer in now. Taking a fork apart is totally different, because it takes a lot of heat. Is it a socketed crown, or internal. If internal, it's new fork time because whoever made that fork was either having a really bad day or didn't know what they were doing or both. I guess that under-filled steerers are more common that loose fork blades, but I still wouldn't take a chance.