Cracked head tube

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David9694
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Re: Cracked head tube

Post by David9694 »

As a teenager, I never got past a Raleigh Clubman (main tubes only) and a 531CS British Eagle. Not that I’m obsessed with full 531 frames or anything, but in 2017 when I first got interested in restoration, we went for months without a single decent RRA coming up on Ebay - even then, all I could get was a 21.5” and a 23” with a ding in the downtube. Now they’re like London buses.
Spa Audax Ti Ultegra; Genesis Equilibrium 853; Raleigh Record Ace 1983; “Raleigh Competition”, “Raleigh Gran Sport 1982”; “Allegro Special”, Bob Jackson tourer, Ridley alu step-through with Swytch front wheel; gravel bike from an MB Dronfield 531 frame.
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531colin
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Re: Cracked head tube

Post by 531colin »

iandusud wrote: 17 May 2021, 6:58am
531colin wrote: 16 May 2021, 5:28pm Not worth worrying about.
The frame itself is pretty average; just the 3 main tubes 531, plain gauge.
Head tube is un-specified (ie cheap) tubing; an artisan framebuilder would have filed the lugs thinner at the ends to reduce the stress-raiser, and probably used a better lugset in the first place.
On the other hand, if you were looking for excitement, you could probably sleeve it internally and silver solder it up; the crack only goes part way round. As above, though, the head tube needs to be straight(ish) when finished.
Whilst I would agree that it's probably not worth repairing I'm pretty sure that those Record Aces were built with a full 531C tube set. I had the opportunity to buy a lot of them from Raleigh at a good price when they cleared them out, selling them on at £200 if I remember correctly.
Now you've made me think about it, I realise I can remember the code for the fifties etc. (small/large transfer, 531 oblique/level) but I can't interpret later transfers! Fork blades have a transfer.
If I owned it and liked riding it I would have a go at a repair by internal sleeving and silver soldering, like I extended this steerer, but i wouldn't buy it to do that!
Image003 by 531colin, on Flickr
Image005 by 531colin, on Flickr
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531colin
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Re: Cracked head tube

Post by 531colin »

9494arnold wrote: 16 May 2021, 6:37pm Overheated on build if it hasn't been crashed I would guess.
Plus might have been run with Headset loose which over time will kill the head tube ( I know it's a bike but not an uncommon problem on a trike where all the braking is generally on the front fork )
Higgins ultralight? ie. a lugless lightweight frame where the head tube lacks the reinforcement of the lugs top and bottom.
fastpedaller
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Re: Cracked head tube

Post by fastpedaller »

jo' bo wrote: 16 May 2021, 10:24pm
AndyA wrote: 16 May 2021, 9:57pm
jo' bo wrote: 16 May 2021, 8:45pm

Taking it to an expert metal fabrication repair facility and getting it fixed is bad advice, ?

Ok what's good advice, throw it away presumably, or use it as wall art?
Here are three reasons why this is bad advice.

1) 531 often cracks after welding
2) Welding next to a brazed joint results in a very messy weld because the zinc comes out of alloy with the brass and vaporises. Porous, dirty weld is the result and likely to crack again
3) The tube will distort from welding, bringing the headset out of allignment

If you wanted to save the frame, take it to a reputable framebuilder who will replace the headtube. Anything less is a bodge
Well that's all very interesting, but I didnt say get it welded did I, I said take it to a,welder who would of course have brazing facilities

As a general rule people who can repair two ton hundred mile an hour vehicles can be trusted to repair an old push bike frame

It really not that complicated , specialist frame builder my $$$$, I'd do it with my aldi arc welder
This was what you said:-
Take it to a,welding shop and get it fixed

There are people here who ask questions to which they need may need (for reasons of safety) a valued opinion from experienced people.
Please don't make flippant statements such as "It really not that complicated , specialist frame builder my $$$$, I'd do it with my aldi arc welder" when you clearly don't understand. More importantly, an innocent new member may get injured after taking your 'advice'
tatanab
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Re: Cracked head tube

Post by tatanab »

531colin wrote: 17 May 2021, 8:30am
9494arnold wrote: 16 May 2021, 6:37pm Overheated on build if it hasn't been crashed I would guess.
Plus might have been run with Headset loose which over time will kill the head tube ( I know it's a bike but not an uncommon problem on a trike where all the braking is generally on the front fork )
Higgins ultralight? ie. a lugless lightweight frame where the head tube lacks the reinforcement of the lugs top and bottom.
As do many more modern frames. I have had 4 trike frames crack around the head in 50 years of trike riding, both lugged and lugless. I think the stress not caused by front wheel braking as much as the side loading when cornering. On a bicycle, loads are mainly straight up and down the forks and headtube, not so on a trike.

P.S. none of the failures were on my 1950s Higgins.
Last edited by tatanab on 17 May 2021, 10:56am, edited 1 time in total.
tatanab
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Re: Cracked head tube

Post by tatanab »

jo' bo wrote: 17 May 2021, 10:34am It's an old push bike frame, that anyone who can use a brazing set can repair to a road going standard
How would you get the brass to run into the dirty faces of the crack?

A serious question, not picking holes. I ask because i know it doesn't work well since I have a frame with a rear dropout which was "cracked" from new. A forging error. The frame builder said "fill it with silver and it will be ok". It is ok, especially in its specific location, but a year or so down the line (late 1980s) the line of the flaw can be seen clearly through the paint and looks for all the world like a crack.
jo' bo
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Re: Cracked head tube

Post by jo' bo »

tatanab wrote: 17 May 2021, 10:54am
jo' bo wrote: 17 May 2021, 10:34am It's an old push bike frame, that anyone who can use a brazing set can repair to a road going standard
How would you get the brass to run into the dirty faces of the crack?

A serious question, not picking holes. I ask because i know it doesn't work well since I have a frame with a rear dropout which was "cracked" from new. A forging error. The frame builder said "fill it with silver and it will be ok". It is ok, especially in its specific location, but a year or so down the line (late 1980s) the line of the flaw can be seen clearly through the paint and looks for all the world like a crack.
So this " dirty" repair you undertook in the 1980s was sufficient to hold the tubes in place ?

I think you answered your own question,

Well flux is the actual answer
tatanab
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Re: Cracked head tube

Post by tatanab »

jo' bo wrote: 17 May 2021, 11:07am So this " dirty" repair you undertook in the 1980s was sufficient to hold the tubes in place ?
Well flux is the actual answer
No tubes involved, it was a forging error as I described. In a non essential place. Here it is, 35 years after being built.
Yes, flux is the answer of course, working with clean materials also helps. When doing minor braze on parts at home I degrease all parts.
100_1415.JPG
jo' bo
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Re: Cracked head tube

Post by jo' bo »

tatanab wrote: 17 May 2021, 11:35am
jo' bo wrote: 17 May 2021, 11:07am So this " dirty" repair you undertook in the 1980s was sufficient to hold the tubes in place ?
Well flux is the actual answer
No tubes involved, it was a forging error as I described. In a non essential place. Here it is, 35 years after being built.
Yes, flux is the answer of course, working with clean materials also helps. When doing minor braze on parts at home I degrease all parts. 100_1415.JPG
Ii commended you for an effective home repair

I'm not sure if it a generational thing or just a,21 century thing, but the number of people who can do basic mechanical engineering with out an over priced expert are few

I could braze/ weld to a good standard when I was 14, they took the trouble to teach that as a life skill at school.
As I could undoubtedly have repaired that as a child, I find the whole you need an exspert to do child level engineering difficult to understand
fastpedaller
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Re: Cracked head tube

Post by fastpedaller »

There's 'repairs' and real repair though. Yes, some braze could be run in the crack but it wouldn't last due to insufficient surface area. The tubing wouldn't last if it was welded (would break at edge of weld probably). The only way would be a new tube, or as has been suggested above a sleeve. I frequently watched a master frame builder (over 40 years experience at the time) in my youth. It's not just a case of blobbing a bit of brass on (especially with thin, fragile metals) , and it could be the subject frame has failed due to inexperience ....... Joint too hot, cooled too quickly?
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531colin
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Re: Cracked head tube

Post by 531colin »

They taught us Latin grammar at school.....any practical skills I have are "picked up" ie self-taught.
If I owned that frame and enjoyed riding it, I would attempt a silver solder repair with an internal sleeve ....the purpose of the sleeve being to hold the fractured tube in place while brazing and to give surface area for a strong repair.
I can soft solder OK and silver solder OK....my welding would embarrass birdshit.
I think you need to be fussier about cleanliness soft soldering than silver soldering; get the work red hot run the flux in and it carries all before it. But for brazing/silver soldering its imperative to work out how to jig up the work to hold it in alignment to run the spelter in.....you can't hold it when its red hot!
With that repaired dropout, is what we see a hiccup in the surface picked out by dirt? I think you could make that repair invisible (under paint) by over-filling the crack and grinding back to smooth.
jo' bo
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Re: Cracked head tube

Post by jo' bo »

fastpedaller wrote: 17 May 2021, 2:14pm There's 'repairs' and real repair though. Yes, some braze could be run in the crack but it wouldn't last due to insufficient surface area. The tubing wouldn't last if it was welded (would break at edge of weld probably). The only way would be a new tube, or as has been suggested above a sleeve. I frequently watched a master frame builder (over 40 years experience at the time) in my youth. It's not just a case of blobbing a bit of brass on (especially with thin, fragile metals) , and it could be the subject frame has failed due to inexperience ....... Joint too hot, cooled too quickly?
You seem to be making a false distinctions between repairs you approve of and those that you dont
.when the only actual qualifications is does it last or not



It would I suggest it would have exaxtly the same surface area it had when new, now clearly it has failed probebly through fatigue, that would likely mean that any subsequent failure would most likely happen on the unrepaired section
mattheus
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Re: Cracked head tube

Post by mattheus »

jo' bo wrote: 17 May 2021, 12:05pm I'm not sure if it a generational thing or just a,21 century thing, but the number of people who can do basic mechanical engineering with out an over priced expert are few

I could braze/ weld to a good standard when I was 14, they took the trouble to teach that as a life skill at school.
As I could undoubtedly have repaired that as a child, I find the whole you need an exspert to do child level engineering difficult to understand
:lol:
jo' bo
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Re: Cracked head tube

Post by jo' bo »

mattheus wrote: 17 May 2021, 4:28pm
jo' bo wrote: 17 May 2021, 12:05pm I'm not sure if it a generational thing or just a,21 century thing, but the number of people who can do basic mechanical engineering with out an over priced expert are few

I could braze/ weld to a good standard when I was 14, they took the trouble to teach that as a life skill at school.
As I could undoubtedly have repaired that as a child, I find the whole you need an exspert to do child level engineering difficult to understand
:lol:
I made a living that exceeded my paper round brazing up the broken chain stays on Raleigh choppers, admittedly, I didnt pass on my secret of slugging the tube together and running a line of braze round it, as any one could do that, rather than give me 2 pounds
fastpedaller
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Re: Cracked head tube

Post by fastpedaller »

jo' bo wrote: 17 May 2021, 3:55pm
fastpedaller wrote: 17 May 2021, 2:14pm There's 'repairs' and real repair though. Yes, some braze could be run in the crack but it wouldn't last due to insufficient surface area. The tubing wouldn't last if it was welded (would break at edge of weld probably). The only way would be a new tube, or as has been suggested above a sleeve. I frequently watched a master frame builder (over 40 years experience at the time) in my youth. It's not just a case of blobbing a bit of brass on (especially with thin, fragile metals) , and it could be the subject frame has failed due to inexperience ....... Joint too hot, cooled too quickly?
You seem to be making a false distinctions between repairs you approve of and those that you dont
.when the only actual qualifications is does it last or not



It would I suggest it would have exaxtly the same surface area it had when new, now clearly it has failed probebly through fatigue, that would likely mean that any subsequent failure would most likely happen on the unrepaired section
Eh? The crack is a crack in the headtube - the crack itself was never previously brazed!
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