Adding cable stops to a frame without wrecking the paint.
 

I know there are all sorts of cable stops that clamp onto the frame, but I really don't like that look, and if I'm working on a restomod I don't need to stay period correct with bolt on cable stops anyway.

I have a 1968 Raleigh Sprite that I'm slowly picking away at, it has an S5 Sturmey in the back, so it has 2 shift cables, this will be a full restomod build, but I want to leave the original paint.

I will be attaching 2 3 gang cable stops on the underside of the top tube, here is what I made, those are 4-40 stainless screws, the frame will get drilled and tapped for the 2 screws, and I will JB weld this piece to the frame as well, which has, supposedly, 2,800 PSI of adhesion strength, and the force will be in shear, not tension. This fitting will be 2 shift cables with brake cable in the center so the greatest force will be applied totally symmetrically.

I will make some single cable stops to go on the underside of the seat stays as well that will get one screw and JB Weld to hold them on to run each cable for each side of the hub.

I will paint these black with some catalyzed automotive paint I have, I'll use more paint getting the spray gun wet that will end up on these pieces...

Here are some pics of the first piece, I do have the right diameter tubing to match the OD of the seat stays on the Sprite as well. I did just run out of oxygen though, so no more brazing tonight...

https://i.postimg.cc/g2q3YzwB/5C00D6...4C3141AB67.jpg

https://i.postimg.cc/BvSHbrHZ/A7419B...8895D6705F.jpg

https://i.postimg.cc/DzxsXxPr/C7388D...955B7728F0.jpg

https://i.postimg.cc/Ssj97cgw/F921D5...A62E8AE775.jpg

Carry on! :popcorn

Not a criticism in any way, but I find it ironic you want original paint but are going to drill a frame to add avoid using a clamp. To each their own.

+1 the 'Carry On' comment.

use a silicone glue like e6000 it will hold it will put the glue on tape it in place wait overnight. and with a little work it will peel off with no damage. yo ucan get the glue about anywhere now including walmart in the crafts section.

This is a clever work around. I can understand preserving the original paint and therefore creating these new cable stops. I don't see any reason why it would not work. Epoxy should hold and the screws will cinch it down until the epoxy cross links. You may want to use a clamp or near the cable stops too just to make sure that you have a uniform thickness of epoxy across the joint. You probably thought of that already though.

Keep the pictures coming.

I don't know that it will look any better than clamp stops, but...................carry on.

I'd use clamp-on stops, but understand your preference. I would just use epoxy and skip the drilling and tapping. I don't think the tubing will be thick enough. My memory is that those old Raleigh frames had tubing thicknesses between 1.4 and 1.8 mm. If your machine screws are 32 tpi then all you would be able to tap is maybe 2-3 threads and only if your tapping was perfect. I'd guess that hand tapping would result in a very sloppy fit. You'd be better off using self-tapping sheet metal screws. In either case, the epoxy would hold the screws in.

Good luck

Personally, I'd use clamp ons. However, if you're going to go this way I don't think the tubing is thick enough. The obvious (to me) solution is using a threaded insert such as a nutsert or rivnut. This is what is commonly used on aluminum frames to provide threaded holes for attaching water bottle cages and other accessories, though they can be used for steel too.

I would not do that, too big of holes too close to each other. and if you are using for brake cables there is a fair of mount of force, so my conservative self would be skeptical of gluing also.

many frames with cable clamps had thin pieces of metal brazed to the frame as stopper to help with the prevent cable clamps from slipping

I've been following and thinking about this, I'm not sure I'd trust epoxy to hold a cable stop that actuates my brake, especially if the epoxy is on top of some vintage paint of unknown adhesion to base metal.

The force on the cable stops creates a shearing force on the screws, so even though there are only a few threads engaged the screws will add plenty of strength to the setup.

JB Weld states their product has tensile strength of 2800 PSI, the 3 gang cable stops have about an inch of surface area, plus the 2 screws, my right hand has a grip strength of 165 pounds, the mechanical advantage of the brake lever will increase this force by a factor of, 10? So tension on the brake cable could be up to 1650 pounds if I pull the lever with all the force I can muster in my right hand, but I will never do that as the rear tire will be skidding long before I get anywhere to exerting the full grip strength of my right hand. So, assuming the screws do nothing, the JB Weld still has plenty of over head to deal with the expected forces, the screws are "belt and suspenders". The screws are 4-40 size. I will remove the paint under the cable stops with a dremel before I JB Weld them on so the glue will be metal to metal.

There are currently 7 cable guides and clips on my Raleigh Sprite, they are dull kind of gross looking galvanized steel, they will be replaced with 4 satin black cable stops which will look much better IMO.

I also need to add some stops to my Hercules 3 speed as it now has a 5 speed hub in the back and I need cable stops for the new cable on it that shifts the NDS side of the hub, that bike is semigloss black, so these home made flameless cable stops will be right at home there.

I don't see how you can run 3 cables with those though?

I have the rear brake cable and 2 shifter cables that all need to be routed on or under the top tube.

The holes in the frame will be 3/64". They are tiny.

I second the hesitation to drilling holes in the frame.

For one the down tube is under tension just by sitting on the bike. Then it is further under cyclical torsion with every pedal stroke. Then following that, the tapped threads are sharp leading to stress concentration. Considering the actual hole size is the most extreme distance from edge to edge inside the bolt threads inside the bore. That makes the hole quite a bit bigger structurally than it appears by eye or the drill bit you used.

Red flags all over the place on this one.

Good cool wet rags, moderate heat, a bit of silver & a post in the frame builders forum for some advice ftom the real talented builders there are all things I suggest.


Fwiw: Why not a real spot weld instead of JB Weld?

I don't know -- what makes me cringe a little bit is that this is an irreversible change to the frame. Also, you want to preserve original paint, but you need to remove paint under the proposed addition to aid adhesion. I dunno. It's your bike, but if it were me, I would want to experiment on something a little less pristine than a '68 Raleigh with original paint. But, it's your bike.

If you re-invent them as guides instead of stops, you could glue / epoxy / JBWeld them on without worrying about the amount of force applied, esp. if you use good compressionless cable housing. I would still remove the paint in the contact areas.

Or perhaps a hybrid - if it's the force associated with the brake cables you're worried about, keep the ones associated with the shift cables as stops, but convert the brake cable ones to guides.

You are correct, but as mentioned in the first post, I am drilling the holes in the top tube ;-)

It just so happens they recently released a new formula, 5,020 PSI now!!!

https://i.postimg.cc/wM912Dfg/B0FE5E...454323E197.jpg

The bike is not pristine, it sat outside in Arizona sun for who knows how many years. The paint is all intact, but it is notably faded.

Is this irreversible? Hardly, it would be simple to zap the holes full with a MIG welder at a later date and refinish the frame.



Is the belief here that at a later date somebody will want to revert this bike back to a period correct stock build? I suppose that could happen, but this thing is going to be a super sweet gravel bike when I'm done with it, fenders/chainguard and all. How many bikes came with Sturmey S5 hubs? Not many, and most all of them that did have had the hubs removed and placed in other bikes. I am guilty of buying S5 hubs that somebody robbed from a working bike, and placing them in a different bike, so I'm stoked for this hub to have a very good chance of living out the rest of its years in the frame it was born in.

I'm sure there are plenty of people that are opposed to resto mod builds, but I'm not, I like modern wheels and tires! I even have a titanium BB for this bike, and some Campy cranks, and I'll be building some 650b wheels for it. Final build weight will be 25-26 pounds with the original rack on it, the bike will positively fly compared to how it left the factory.

At some point in the future will somebody undo all that I'll have done to this bike? They'll take a super sweet, efficient, all terrain gravel/asphalt smashing touring townie and turn it back into a 38 pound bike with super heavy wheels (no tire selection) and crap brakes? Maybe, but I won't be alive to witness it.

FWIW, I'll take this bike on gravel centuries and I'm sure I'll whip the ass of some "french geared bikes" in the process ;-) If I left the bike stock, I would not ride a dirt century on it.

Building this bike up "properly" will ensure that it lives a glorious life under my ass :-)

What is going to hold the screws? If you don't have some sort of braze on or rivnut for the screw to go into wit likely won't stay tight for long.

I'm going to tap the hole I drill in the frame, not a lot of threads, but should be enough. I tested this set up with scrap tubing (without the JB weld) to see how well the screw tightens down and it did just fine, its a small screw, and the old Raleigh 3 speeds have thick wall tubes, notably thicker than my test piece, so it will work even better in situ than my test.



Painting tiny pieces with an HVLP gun! And not have them blow across the garage...

I put screws through foam board, cut the tips off the screws off and super glued the pieces to the top of the screws, I'll grind the super glue off the back once they are painted for proper jb weld adhesion.

https://i.postimg.cc/kGDBL7mp/A54F29...0804622F9A.jpg

It's a 1968 Raleigh Sprite with a characteristically dull Bronze Green paint job, like a gazillion others. Rip that paint right off and add those braze-ons.

Since you mentioned that you are working with 2K paint, treat the frame to a glorious coat of dignified black. It'll be an improvement and it won't result in holes in the frame. Plus, there are those gazillion others that can exist as representatives of original, unmodified Raleigh Sprites.

-Kurt

Yep.

I did just strip all the parts off the frame and it is a bit more beat up than I'd like form the rack and all the clips that were on the frame, nobody would call it pristine, but it's not a total rat rod either, a full paint job is tempting, but losing the "5 speed" on the downtube is a tough one.


Paint gun is not out yet, no holes drilled yet, I'll think on it...

I am sure it has been mentioned but those housing stops are more for carbon and alloy frames but they usually have some sort of anchor for the screw

This + a bazillion. I like being able to rely on my brakes. While I've trusted epoxy and screws/rivets to keep a head badge in place, I wouldn't do the same with either brake or derailleur fittings that are subjected to some not-insubstantial strains.

DD

Wondering what the spec is for the paint adhesion to the metal frame...that's the weakest link

So, JackBombay, I feel for you, you asked for opinions. Everybody has one. And the feedback is useful. All of it. But it is your bike and your butt that is at risk. Weigh out the advice and do what you think is right.

One line of thinking is that if this does not work out, and let's say the epoxy lets go, then you have the holes in the frame and you still need to get the cable guides on. And you still have the stopping power of your front brake. Your plan B is that you can still braze cable stops right over holes. My local body shop says they can mix a pint of 2K paint if I bring in a part of the bike to color match to. But this is Plan B.

I don't see why Plan A won't work or would be so disastrous.