Adding Cable Stops to Steel Frame

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531colin
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Re: Adding Cable Stops to Steel Frame

Post by 531colin »

I find that generally the only "problem" I get with brazing/silver soldering is getting the parts to be joined jigged up adequately.

Say you are adding a cable stop to a frame tube. The cable stop weighs next to nothing, so the blowtorch flame will blow it out of position, unless you create some sort of jig to hold it in place. But the jig will usually be metal, so that adds a heat sink which can easily be bigger than the cable stop itself. Then, even with it jigged up, you need to operate blowtorch, flux and solder; its pretty easy to run out of hands.

My solution was to "tin" both the bit of frame tube and the stop. (in this context, "tin" means to coat the bonding surfaces with solder.)
Then, I can hold the stop in place with (eg) a bit of mudguard stay wire with one hand and operate the blowtorch with the other hand.
There is generally enough flux left on the parts from the tinning, unless you overheat the flux.
Jupestar
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Re: Adding Cable Stops to Steel Frame

Post by Jupestar »

531colin wrote: 25 Oct 2021, 4:02pm I find that generally the only "problem" I get with brazing/silver soldering is getting the parts to be joined jigged up adequately.

Say you are adding a cable stop to a frame tube. The cable stop weighs next to nothing, so the blowtorch flame will blow it out of position, unless you create some sort of jig to hold it in place. But the jig will usually be metal, so that adds a heat sink which can easily be bigger than the cable stop itself. Then, even with it jigged up, you need to operate blowtorch, flux and solder; its pretty easy to run out of hands.

My solution was to "tin" both the bit of frame tube and the stop. (in this context, "tin" means to coat the bonding surfaces with solder.)
Then, I can hold the stop in place with (eg) a bit of mudguard stay wire with one hand and operate the blowtorch with the other hand.
There is generally enough flux left on the parts from the tinning, unless you overheat the flux.
I'm still considering this - although i've now ordered the solder, so i'm commited to try. A heat resistant jubille clip would seem to be ideal. but in the real world, I'm eyeing up a steel clamp with a plumbers mat between it and the tube/cable stop. It will block 360degree access. but i should one hand for the solder, and one on the torch. Flux already layed.

EDIT: - This set up seems more suited to the double ones, which sit on the tube rather than the single ones, where is like trying to clamp two snooker balls together. Hence why you method of sitting in on a filed nut first is sensible.

I've spec'd this and i'm optimistic. I'm currently using a plumbers wrench for the clamp. I'd prefer it to be a lighter.

The biggest issue i see if that i'll only be able to do one at the time. Ideally once set up, you would just move along and do them all.
Last edited by Jupestar on 25 Oct 2021, 4:30pm, edited 1 time in total.
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531colin
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Re: Adding Cable Stops to Steel Frame

Post by 531colin »

Ideal would be a strap wrench, with the strap made of something which doesn't conduct heat, and will resist red heat
.......answers on a postcard......
Jupestar
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Re: Adding Cable Stops to Steel Frame

Post by Jupestar »

What do frame builders use?

An apprentice with Kevlar gloves?
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531colin
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Re: Adding Cable Stops to Steel Frame

Post by 531colin »

Jupestar wrote: 25 Oct 2021, 4:34pm What do frame builders use?

An apprentice with Kevlar gloves?
Experience? :wink:
Jupestar
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Re: Adding Cable Stops to Steel Frame

Post by Jupestar »

531colin wrote: 25 Oct 2021, 4:02pm My solution was to "tin" both the bit of frame tube and the stop. (in this context, "tin" means to coat the bonding surfaces with solder.)
Then, I can hold the stop in place with (eg) a bit of mudguard stay wire with one hand and operate the blowtorch with the other hand.
There is generally enough flux left on the parts from the tinning, unless you overheat the flux.
This seems like a very good idea. Once its in place presumably you could increase the solder. Also what is stopping you from adding more flux with a brush before you start the torch.

Getting the position just right is obviously vital, no point having a wonky cable stop. Overall i'm still working on this. Ideally, i'd clamp them, run a cable through them to ensure alignment, remove cable and solder them to the frame. This requires fashioning at least 2 heat resistant clamps. The only thing i can thing is protecting the jaws of a clamp with a fireproof mat. Easier said them done, and i don't really have any suitable clamps either.
Jupestar
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Re: Adding Cable Stops to Steel Frame

Post by Jupestar »

Other issue is just making sure you don't solder the clamp to the tube. I have a feeling the solder i've ordered will be sitting around a while.
fastpedaller
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Re: Adding Cable Stops to Steel Frame

Post by fastpedaller »

A good conundrum. I also wonder how frame builders do it. Clamping the stop isn't without its issues - The stop could collapse whilst being heated, due to the combination of clamping force and heat, alternatively, it could just all fall off due to expansion. I like 531 Colin's tinning method....... could it be that if the frame is held in the correct position such that during the heating process the guides are on the top of the tube, gravity helps, along with a 'metal spike' held in the left hand to assist in keeping the stop from moving when the flame is brought into play? As soon as the silver solder melts and solidifies the 'spike' can be removed. I could anticipate putting a stop on might take more time than brazing a lug :lol:
fastpedaller
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Re: Adding Cable Stops to Steel Frame

Post by fastpedaller »

A google search came up with this...... It's easy in hindsight, because the clamping is done at a distance from the cable stop or guide.

https://villaveloframes.wordpress.com/2 ... de-holder/

The downtube boss brazing jig is good as well!
Jupestar
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Re: Adding Cable Stops to Steel Frame

Post by Jupestar »

1min youtube video. Showing clamps.

https://m.youtube.com/watch?v=KjC2XbGPBQM

There is also a longer video of him fixing the braze-ons.

The clamps are $99 for 3. With the additional issue they are in the USA.
Jupestar
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Re: Adding Cable Stops to Steel Frame

Post by Jupestar »

fastpedaller wrote: 25 Oct 2021, 6:27pm A google search came up with this...... It's easy in hindsight, because the clamping is done at a distance from the cable stop or guide.

https://villaveloframes.wordpress.com/2 ... de-holder/

The downtube boss brazing jig is good as well!
Genius.
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531colin
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Re: Adding Cable Stops to Steel Frame

Post by 531colin »

I have just remembered what could be another piece of this jigsaw; Brucey recommended "Tipp-Ex" to coat bits of metal you don't want to silver solder together.....viewtopic.php?f=5&t=138869&p=1503749&hi ... x#p1503749

I'm sure you could modify carpenters' G cramps to make those brazing clamps. He is right to put the clamp screw on the cable stop, its the smaller heat sink. Modify the other end to sit on a round tube, maybe drill them to take say 10mm threaded stud & nuts to keep them spaced and lined up?

Re the problem of clamping 2 round things together (cable stop on frame tube) .....I think I would file a small flat on the cable stop, opposite the slot?
KM2
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Re: Adding Cable Stops to Steel Frame

Post by KM2 »

You can wire the stop to the frame , as it has a hole . Use two wires so the pull equally on the stop and twist the wires using pliers.

Heat the stop, not the tube, it will conduct. Just dab the silver rod, it’ll flow if warm enough and the stop and tube are in good contact.
Jupestar
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Re: Adding Cable Stops to Steel Frame

Post by Jupestar »

531colin wrote: 26 Oct 2021, 9:21am

Re the problem of clamping 2 round things together (cable stop on frame tube) .....I think I would file a small flat on the cable stop, opposite the slot?
Right wow! only 2 years since i intended to do this, and finally! I limped the bike along without any gears for most of this time, then spent a while dealing with a stuck seat post, worked out a solution for rear mech hanger, took the paint off, and today i did the cables stops.

2 doubles on the top tube (FD and RD),
2 singles on the right seat stay (RD).
1 Single on the seat tube (FD top pull)
1 single on the down tube (FD bottom pull, or RD)

Why two options of the FD/RD, i had a spare cable stop so i used it between the existing cable guides on the down tube. where not enough space to run two.

Clamping etc. I used a £6.99 camera clamp from Amazon, put plumbers mat in the jaws to reduce the heat sink.
Solder - i used flat strips of silver solder and put them between the cable stop and the frame before i clamped. then just added a bit around the edges as needed. i used too much initially so need to work out how to get the exesss off the top tube! It was I bit fiddly setting it all up, but it worked well. Lots and lots and lots of flux helps.
Cable stops - round on round problem, i brought the double ones which are joined and tube shaped, then where i wanted a single i hacksawed it in half (hence the spare). so i had a nice tube shaped rounded bottom on single to help with the clamping.
Torch - just a basic butane torch did it easy enough.

Job done - woudl rather the ones on the seat stay actually lined up - but you live and learn :o)

Now just to get rid of the excess solder, and then repaint the bike.. couple more years i'm not in a hurry!
Brucey
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Re: Adding Cable Stops to Steel Frame

Post by Brucey »

Jupestar wrote: 9 Oct 2023, 3:03pm .....i used too much initially so need to work out how to get the exesss off the top tube.......
Now just to get rid of the excess solder, and then repaint the bike.. couple more years i'm not in a hurry!
good work fella! Dremel tool required for clean-up

cheers
Brucey
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