# Gotcha's for riveting cable stops on carbon



## rockyuphill (Nov 28, 2004)

I'm looking at riveting on some cable stops on a carbon frame to change the cable routing to the downtube. I'm looking at using the Nova rivet-on stops and some aluminium body/aluminum mandrel blind rivets and epoxy. The frame sounds considerably thicker on the bottom surface of the downtube in a tap test. Aside from the more obvious thing of staying out of high stress areas near the edge of the downtube, are there any gotcha's to watch out for?

The rationale for using the alu body/mandrel rivets is that I want to use them to positively locate the stops so the epoxy can hold them, but I want the mandrel to snap before it starts to exert a lot of force on the edge of the hole that might initiate cracking. I assume that the hole in carbon needs to be very precise to make sure the rivet doesn't try to pull through the hole. I assume it helps to have extra grip length to get some deformation and curl on the rivet on the inside since there's no way to get a washer on the inside of the tubes to back the rivet. I assume it would help to get a bit of epoxy in the hole so that the expanded rivet is embedded in epoxy to help reduce the potential of crack propagation from the hole. 

I assume that you also want a very snug fit for the rivet in the cable stop holes so there is no slop. Does anyone have the dimension for the holes in the Nova aluminium cable stops, are they a 3/32" or 1/8" rivet size? (Nova doesn't give the hole dia. spec)

Any of those assumptions completely off base?

Thanks for the advice.


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## findhan (Jun 8, 2010)

Hey man,

You're wright in your thinking but its always optimal to not machine carbon (i.e. drilling it) Drilling carbon is always a balls (especially with a hand drill) and although it is highly likely to be ok, especially if glueing around the rivet as you say, its probably best to try another method first: 

Couple of questions, 
What bike are you thinking on modifying; even thought it definately will be thicker on the lower side of the downtube, if its a light xc build, I would stay away from rivets cause in my opinion, they could cause a bit of delamination when the clamping force is very high.

Im assuming these are cable stops for shifters as opposed to brake lines? If it was just break lines, I would remove a bit of paint and bond them on with epoxy as there would be no/minimal peeling force acting on the adhesive. If its shifters, there could be a reasonable force so you might want to avoid just bonding them on as the adhesive would be loaded in peel which is usually a 'no-no'. However and I do stress this, it might be worth trying this method first as at least you arent putting a hole in your frame. The other thing is, that although loading in that manner is usually frowned upon, I would guess the strength of the epoxy could outweigh the force in the cable so I would definately give that a go first.


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## Adam_M (Aug 8, 2008)

Alternative solution would be to go to full length outer and hose guides - much lower firces involved so could be glued on anywhere.


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## damnitman (Jan 30, 2008)

Shoe Goo use #943...(use #942 was to secure the headlamp wires from my gen hub to the fork leg)


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