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Removing Cable guides on BB

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Removing Cable guides on BB

Old 12-06-21, 01:29 PM
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Wet Coast Rider
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Removing Cable guides on BB

This is more of a frame restoration question rather than a frame building question so apologies if this is the wrong place. I do enjoy lurking on this subforum and I figure you all are the experts on manipulating steel frames so I came here first.
I recently acquired an unknown full Reynolds 531 frame that was in rough condition but with no dents or major rust issues. The historians over on the Classic and Vintage forum helped me identify it as a Ď73 Peugeot PX10.
At some point someone brazed on brake cable guides on the top tube and gear cable guides on top of the BB.
I find the BB mounted guides really ugly and as I plan on building the frame as a 1x10 I really have no need for the front derailleur cable guide.
I have files, a dremel, an angle grinder and a plumberís propane torch. What would be the best/safest approach to removing these? Or am I crazy to try?
My initial thoughts were to use a cut off disc and then grind until I reach the braze (probably with the dremel, the 5Ē grinder is a bit scary to have that close to all those tubes and stays). Following that I could use my file to clean up the braze.
There are framebuilders in my city that I could try and contact but like a lot of us these days I am trying to keep costs down.
Thanks!
Ugly left over braze.


This one I especially want to get rid of as I donít plan on running a front derailleur.
SPIli

Last edited by Wet Coast Rider; 12-06-21 at 01:32 PM. Reason: Spelling/clarity
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Old 12-06-21, 02:44 PM
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I would take them off carefully with the angle grinder (cutoff wheel followed by flap disk) until the last bit, where a narrow belt sander (I think sometimes called a "dynafile") is better. A grinder will always slightly gouge a round tube. It doesn't matter if you do structurally because the BB shell is very thick, but obviously and quite rightly it will cause you to weep for many weeks.

Also remove that bubbly brass schmoo on the edge of the BB shell while you're at it... whatever that is
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Old 12-06-21, 03:31 PM
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79pmooney
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Not a frame builder but I have spent a few hours with those 5" grinders. I'd shield the frame tubes with appropriately cut up and bent tin cans. (I used to build and repair boats. Used them for early fairing because they did real work. Bought my current to grind down concrete on my porch from cracking and shifting. First thing I did was remove and toss the guard. I treat it like a rifle. Very effective and rather dangerous.
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Old 12-06-21, 04:07 PM
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Framebuilder and painter here so adding and removing braze-ons is standard procedure. Man is that some ugly and incompetently brazed on BB bosses. Whoever was using the torch dribbled brass on down the shell while trying to attach the guide. Ugh. Those type of bosses became unpopular with builders because a certain percentage were sure to come loose. A hard pull on the cable trying to shift gears can start their demise. They start to crack at the point towards the front and eventually keep cracking. And it is hard to get paint behind the bosses.

My suggestion is to use long handled vise grips or the kind of large pliers that have an angled nose. I've ripped them off with those. They come off easier than you think under your own power if you can leverage part of the pliers somehow. I wouldn't use power tools because of the risk of real damage with the slightest slip. Then I would file the brazing material away. Square files that aren't wide can do that job. You have a lot of awful looking dripping brass that has to go anyway so you just have to get at it with a file.
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Old 12-06-21, 09:10 PM
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Removing them with heat will destroy a lot of the paint, so be prepared for a repaint. But you're going to need to repaint anyway, to get rid of all the nasty brass splatter whoever brazed those on left for you. I've probably removed hundreds of those, when Trek's marketing department decided to switch from over-the-shell to under-the-shell cable routing. Air-propane heat won't cut it; you'll need oxypropane or oxyacetylene to get things hot enough. Keep the heat on the shell until the braze melts, knock the piece off, then brush with a wire brush to get rid of the excess brazing material. If you do it well, a little sandpaper is all that is needed to smooth things out for paint.
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Old 12-06-21, 11:57 PM
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unterhausen
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I'm curious about that blob, the brazing holding the cable guides on looks okay. I'm curious if it's there for some other reason, like covering up a serial number or something
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Old 12-07-21, 05:56 AM
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Originally Posted by unterhausen View Post
I'm curious about that blob, the brazing holding the cable guides on looks okay. I'm curious if it's there for some other reason, like covering up a serial number or something
That was my thought, as well. It looks too far away from the guide to have dripped off while brazing on the guides. Someone tried to cover a serial number or fill a crack or gouge in the shell.
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Old 12-07-21, 06:54 AM
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Doug Fattic 
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In Picture # 2 some of the BB threads look golden like they might have needed to have added some brass to damaged threads. I haven't changed my opinion that those blobs on the outside were the result of really sloppy brazing. If the repairer was trying to add brass on the outside for any reason besides adding those bosses, he should have been able to smooth the brass out with his torch. If there is any brass on the threads then mechanically removing the boss is the best option. However it comes off, some filing is in order.
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Old 12-07-21, 08:01 AM
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No doubt it's horrible brazing. It looks like they burned the bb shell itself up by the guide, which is a good trick.
Would be interesting to know if they got penetration under the guides. If the shell is any indication, the answer would be no. But I wonder if it was different people, one of whom should never have lit a torch.

I see what Doug is saying about inside, there is a fairly sharp line around the golden glob. Probably got filler in there by mistake.

that would be a good name for an award for bad brazing, "The golden glob award"
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