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Bottle cage screw/rivnut loose


paul_ct

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I'd hoped to attach a pump below the bottle cage, but the one screw holding the cage won't come out because the rivnut in the frame somehow unwelded itself from the aluminium while I tried to loosen it.

 

Of course it can't be tightened either, so now it rattles too.

 

The cage is in the way, so I can't grip the rivnut to try and turn the screw out. I'm a bit worried about cutting/drilling it off in case it drops inside the frame.

 

Has anybody tried this and have any advice?

 

Thanks. :thumbup:

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Cut the cage off so you can grip it with a vicegrip to get it undone - then you might be able to tighten it with a rivnut tool

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removing a rivnut will always result in the one half falling into the frame. Take out your BB and see if there is a hole into the downtube where you can remove it. Or your headset at the top. some frames have open holes in these places. If not you stuck with half a rivnut in your downtube. I had this problem with an old MTB I was building up, I ended up squirting some gemken glue through a plastic pipe into the bottom of the downtube through the rivnut hole, which glued the broken rivnut to the inside of the frame to stop it rattling around.

 

the you need to find a company that sells rivnuts and someone who has a rivnut gun to replace it.

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Seems like you will probably have to break/damage your bottle cage.

I have had this issue on an Aluminium Cannondale.

Try wedging a screwdriver between the bottle cage and flange of the rivnut. This may give enough grip to unscrew the capscrew.

Then you could just tighten up the rivnut with a rivnut tool, or if it is damaged, drill it out and replace with a new one.

The cost about R1 or so from places like BMG.

 

I made my own tool, piece of flat bar, a cap screw (M5 I think it was), and a normal nut.

Its a piece of cake to install them.

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I made my own tool, piece of flat bar, a cap screw (M5 I think it was), and a normal nut.

Its a piece of cake to install them.

 

Please could you post a pic of your home made tool for installation and or tightening an existing rivet nut? Sure everyone would benefit from it.

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Please could you post a pic of your home made tool for installation and or tightening an existing rivet nut? Sure everyone would benefit from it.

No hassle, I will take a picture tonight and post it.

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Thanks everyone.

 

I'll definitely lose the cage. I tried getting a screwdriver between the cage and the nut, but they're too close together. I'll check for holes in the frame. Hopefully I don't have to glue the leftovers inside.

 

Looking forward to seeing that tool, too.

Edited by notstpaul
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Ok I finally remember to post pics of my home made rivnut tool.

 

Pretty simple. Small aluminium flat bar. Drill appropriately sized hole, rivnut, capscrew and a nut.

post-35520-0-78150700-1382789281_thumb.jpg

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Break down of parts

 

Sorry my phone won't load that picture. Will have to post from my laptop.

Edited by quintonb
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Ok I finally remember to post pics of my home made rivnut tool.

 

Pretty simple. Small aluminium flat bar. Drill appropriately sized hole, rivnut, capscrew and a nut.

Thanks for the picture.

 

I eventually had to cut off the bolt and file off the rivnut. Of course the bottom half dropped into the frame so I took off the headset to remove it.

 

Next will be to get another rivnut and to try the tool in the pic.

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Thanks for the picture.

 

I eventually had to cut off the bolt and file off the rivnut. Of course the bottom half dropped into the frame so I took off the headset to remove it.

 

Next will be to get another rivnut and to try the tool in the pic.

Glad you got it out. I will post better pictures tomorrow when I get to work.

It's dead simple and shouldn't cost more than R5 for the tool and the rivnut.

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The 'proper' rivnut tool has a hardened steel threaded bit to pull/rivet the nut - a normal bolt might break when being tightened up with the DIY tool, esp. the smaller diameters.

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The 'proper' rivnut tool has a hardened steel threaded bit to pull/rivet the nut - a normal bolt might break when being tightened up with the DIY tool, esp. the smaller diameters.

The cap screw I used is a high tensile 12.9 grade. More than adequate for this application.

The rivnut is designed to "collapse". It basically causes a "bulge" when you tighten the nut up. A proper rivnut tool is the answer if you going to use it everyday and all day. But for the once or twice in a few years the diy tool is cheap and very effective.

Edited by quintonb
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The cap screw I used is a high tensile 12.1 grade. More than adequate for this application.

The rivnut is designed to "collapse". It basically causes a "bulge" when you tighten the nut up. A proper rivnut tool is the answer if you going to use it everyday and all day. But for the once or twice in a few years the diy tool is cheap and very effective.

 

Like your thinking there Q, you should mention that in your spec of the tool.

 

I managed to 'screw up' a good few rivnuts and bolts in another project before I went out and bought the proper tool.

Edited by kosmonooit
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