Corroded chainring bolts

[531colin]

Not on my bike, my son in law bought a secondhand mass=produced bike and of course the bolts weren't greased on assembly so now they are stuck, although the bike has hardly been ridden.
I have one of the tiny tools which are supposed to hold the other end, but I find it hopeless.
I was going to grind a bit of sheet metal so it has a "peg" which will locate in the hollow bolt, hold my homemade tool in the bench vise so I can bear down on the chainset while undoing the Allen key end.
A cone spanner should be thin enough, and hard enough?
The chainset is currently warming itself by the log-burner with a drop of oil on each bolt.
Anybody got a way of doing this job?

[fastpedaller]

I have found that an old hacksaw blade (or 2 together) will fit nicely in the slot of such nuts. ETA to stop them turning!

[reohn2]

If they're proving that difficult I'd WD40,GT85 or Plus Gas them liberally for a few days with repeated applications,then try the hacksaw blade trick.
Failing that,drill 'em out and fit new ones.

[Brucey]

the kind of blade that is used in reciprocating saws is made of thicker steel which is equally strong and makes a good starting point for a ground-up tool to fit the back of the bolts. Also a help is direct heating, eg using a miniature blowtorch on the bolts. The bolts don't come free easily when they are hot, but the bonds of corrosion are weakened by repeated heating/cooling cycles.

I quite like using stainless steel bolts to replace the standard ones.

cheers

[slowster]

If when you say stuck you mean the two parts of the bolt are stuck together and rotating in the chainring, then this method might be worth trying:

https://www.youtube.com/watch?v=E6SCwijgdyQ

[rjb]

I would use a mineral oil release spray to soak the bolts. (I use freeway - this was used when I was working but you may find something equivelant) Tightening the bolt is recommended to release the corrosion joint before unscrewing. Tapping the Allen bolt with a hammer while the nut is supported may also break the joint. In situations like this I support the Allen key in a bench vise and rotate the crank to get things moving.

[Eyebrox]

This will do the job. Extra purchase. And handy ...every five or so years.

[alexnharvey]

Can you clamp the little tool and chainring together and then get medieval on the Allen key? I.e. clamping the flat of the tool so that it's pressed into the slot but you can still access the Allen socket.

[Des49]

VAR make a nice looking tool for this task, never used one myself but they seem reasonably priced. Not sure how strong it is for really stuck bolts though. (edited:- maybe not so cheap, on ebay from USA at $60 without p&p)

https://www.vartools.com/en/combined-to ... r-p828.php

[Greystoke]

Personally I'd resort to the 'blue tipped screwdriver' it clearly needs some heat

[Norman H]

In the absence of a suitable blowtorch I've used an electric soldering iron.

[Patrickpioneer]

would a ground down old putty knife old the bolts?
Pat

[531colin]

Got it!
I was fairly gentle with it yesterday, of the inner ring bolts all but one came out with normal force on the Allen key....its always one, isn't it?
This morning that one yielded to the "Allen key in the vise and turn the chainset" trick.
On to the next set of bolts.....all but one came out when I clamped a cone spanner in the vise to hold the slotted bit, and turned the other bit with the Allen key.
So for that last one bolt I ground a bit of a flat on the cone spanner with a central "peg" to fit the hollow bolt, and it worked a treat. Much better purchase on the slotted bolt with a newly-ground, sharp flat edge than with the random edge of a 30 year old spanner!
….no cone spanners or knuckles were harmed, and no extreme violence was necessary!
Thanks for the input!

[Brucey]

yay!

[NetworkMan]

..... or knuckles were harmed ........

On my last bicycle rebuild job I made myself put on the leather gardening gloves before any job with the slightest risk of knuckle damage, for that one big heave that's needed. For what must be the first time I completed the whole job with knuckles intact. Gardening gloves are highly recommended for pedals, crank bolts, cassette lockrings etc., even when you know (or think you know) that things will be OK for this one simple little job!