DBR Apex ti bottle boss woes

Thanks for all your advice thus far, sadly the Stanley blade, screwdriver blade method is not working as the riv nut is quite loose so it's not looking possible to wedge something in to stop everything spinning. Add to that that the riv nut is so brittle it is also starting to crumble, I'm now stuck a bit and hoping you all have some other methods that can be tried.

Has anyone had any experience in sending their frame off to get this issue resolved, as at least then I have that as as last resort if nothing else works.

The riv nut is Alu, so would some sort of treatment melt it away but leave the ti? I know it isn't pure ti, but some form of ti alloy, so maybe not such a good idea, just trying to think of other possibilities.

bottle boss

would caustic soda melt it out? but am unsure of effects on the ti,either melting and staining to the metal?

Re: bottle boss

matthew71":5nrtfggv said:

would caustic soda melt it out? but am unsure of effects on the ti,either melting and staining to the metal?

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Not sure, and not willing to try unless it's tried and tested. Hopefully others will have tried and can report back. Cheers for the idea though!

As the rivnut is alu and seemingly age hardened, my method of resetting it has gone out of the window.

Andy R's method sounds a winner and the expanding foam part is a great permanent solution to rattling debris.

Andy R's idea of the foam is just the thing for the little rattly thing I have in one of my chainstays. Will be trying this when I can get a can

Ian,

I had a similar problem with my B4.

I'd go with Andy B's suggestion...combination of angle grinder (very carefully), Dremel and hand file as much as possible of the flange, followed by punching the stump into the tube.
Great if you can rattle the stump out of one of the holes. The pulled rivnut's not huge, but you'll need a hole at least 12mm dia to get it out. Might be worth tyring to enlarge the BB hole, it's the thickest, least stressed hole.

Otherwise, position the frame on its side, injected a little epoxy through the BB hole to hold the remnant quietly at the BB end of the downtube.
Cleaned up the hole and fitted a new rivnut.
Happy to lend an M5 rivnut kit if you get that far...

All the best,

Thanks for the offer Dan, I may take you up on it. I've just heard back from De Ver cycles and they think they can sort it all out for £50, though a lot of that is the postage to and from whoever they use, so I need to decide whether this is money well spent, or to have a stab myself. So far I'm thinking that I'll need to grind the bolt heads down, then drill through the remainder of the bolt. The bits that fall into the frame from this should be small I assume and I can get these through the holes in the tubes. After that my plan would be to try and drill the riv nut at the sides or filing them down, trying to remove a section so that I can try and fold the remaining riv nut and pull it through the hole, leaving nothing in the frame.

Any thoughts on whether this approach will work? In theory it should, but in practice I'm sure it will be more tricky than the simplicity suggests.

ishaw":1gussjgl said:

So far I'm thinking that I'll need to grind the bolt heads down, then drill through the remainder of the bolt. The bits that fall into the frame from this should be small I assume and I can get these through the holes in the tubes. After that my plan would be to try and drill the riv nut at the sides or filing them down, trying to remove a section so that I can try and fold the remaining riv nut and pull it through the hole, leaving nothing in the frame.

Any thoughts on whether this approach will work? In theory it should, but in practice I'm sure it will be more tricky than the simplicity suggests.

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You'll have a job drilling the bolt out, as how will you stop it rotating in the frame? The same goes for drilling out the rivnut as it will rotate in the frame too.
I still reckon that grinding or filing off both the bolt head and the head of the rivnut, punching the remainder through into the frame and, if it can't be removed, sticking it in place to stop it rattling is the best and maybe only way.
It's worked for me, anyway.

Or, if you have access to oxy-acetylene or oxy-propane, assuming the rivnut is aluminium, you could always melt it out.