Removing bottlecage mounts
- Thread starter Misplaced
- Start date
Grip
Yeah, yeah... blah, blah.
There's basically 2 types... "nutserts" that are fitted like a pop rivet and "braze-ons" that are brazed into the (steel) frame. both are fitted into a 7mm (approx) hole so if you remove them that's what you're going to be left with.
The braze-ons can obviously be removed with the aid of an oxy torch. Be careful not to over heat the tube locally as the centre of the major tubes are fairly well stressed already AND they have a couple of 7mm holes in them. It's a fairly common place for frames to develop cracks and stuffing the heat treatment of the tubing by over zealous heating is not going to help.
The nutserts can only be removed by drilling them out... which will leave you with that 7mm hole AND the underside of the nutsert rattling round in your frame. OK if it's the seat tube, but often very difficult to remove if it's the downtube.
If you're wanting to clean up the look of the frame for painting etc. I'd suggest leaving the threads as is and simply filling them with a couple of nice small M5 dome head cap screws.
The braze-ons can obviously be removed with the aid of an oxy torch. Be careful not to over heat the tube locally as the centre of the major tubes are fairly well stressed already AND they have a couple of 7mm holes in them. It's a fairly common place for frames to develop cracks and stuffing the heat treatment of the tubing by over zealous heating is not going to help.
The nutserts can only be removed by drilling them out... which will leave you with that 7mm hole AND the underside of the nutsert rattling round in your frame. OK if it's the seat tube, but often very difficult to remove if it's the downtube.
If you're wanting to clean up the look of the frame for painting etc. I'd suggest leaving the threads as is and simply filling them with a couple of nice small M5 dome head cap screws.
Spanky_Ham
Porcinus Slappius
is that because their not aluminium and would affect the outcome?
or two different metals?
spanky is just interested in anodising and the pretty shiny results
sorry for the thread jacking.
s
Misplaced
Formerly Unfit
Correct, stuffs up the chemical reaction process
NCR600
Likes Dirt
Pretty high. Last time I bought some they were 47 bucks per bag of 100. (RS components stock number 623-5527)
If you can find someone who's already using them for something else, I'd reckon a 6 pack would have you sorted.
Grip
Yeah, yeah... blah, blah.
No problem replacing them at all, but make sure of a few things....
A/ don't drill the old nutserts out with anything bigger than a 6mm.
B/ it can be tricky (depending on position of the nutserts) to get a "normal" pistol drill into position to drill them straight. You DO need to drill them straight so as to ensure you don't damage the existing holes (i.e. the frame) so you may well need to find someone with a right angle drill to get into the tight spots and allow you to drill straight.
C/ as I said before... this tends to be a high stress area WITH HOLES, so it's important that when refitting the nutserts you don't "crush" the frame tubing. Many tube manufactures provide a lbs-per-sq-inch rating that should be exceeded when fitting nutserts to their particular tubing. Unfortunately even the "cheap" nutsert tools are expensive and they don't come with any sort of pressure/torque indicator... so it's a matter of doing it by feel and not going ape on it.
D/ You don't need to buy nutserts in bulk. Most good fastener/bolt shops will have them in stock and sell as many as you need. They are simply called M5 Nutserts. But as I said the tool is expensive. You're better off getting them put in for you. Try your LBS or sheet metal shops (nutserts are often used in sheet metal work).