Copperslip

[Profpointy]

[QUOTE 4037814, member: 9609"]I would have thought copaslip on push bikes was a bit OTT, i would have thought any grease would do the job adequately. The only place I ever use it is on stuff that gets hot like drum and disc brakes on cars and trucks.

and I don't mean on moving parts, just things you may need to loosen off at some point in the future[/QUOTE]

whilst any grease probably will do, coppaslip is the proper stuff - and a lifetime's supply costs what? a fiver maybe. Also things do corrode together and coppaslip is supposed to prevent that.

That said, i couldn't find my coppaslip last time so confess I might have used grease. But siezed pedals etc are a pain, so I'd rather use the pukka stuff.


Don't think the "bolts should be dry" point upthread is actually right - I thought the idea was they should turn freely and the torque measured (or felt) is that which is stretching the bolt rather than not turning in the hole so to speak. I'm sure I read that on the internet so it must be true - it seems logical anyway

 

[raleighnut]

[QUOTE 4037814, member: 9609"]I would have thought copaslip on push bikes was a bit OTT, i would have thought any grease would do the job adequately. The only place I ever use it is on stuff that gets hot like drum and disc brakes on cars and trucks.

and I don't mean on moving parts, just things you may need to loosen off at some point in the future[/QUOTE]
Grease doesn't stop seizing though, in fact certain grease promotes corrosion (soap in the formulation)

 

[simon.r]

Copper grease is great.

I put a smear on all threaded components on a bike when I'm building or maintaining one and I've had nothing but good results.

 

[raleighnut]

[QUOTE 4037910, member: 9609"]can't say I have ever come across anything smeared in grease that has went rusty.[/QUOTE]
I should have put Galvanic corrosion, that's why Vaseline is better on seatposts (inert)

 

[DaveReading]

I seem to recall, some time around 1960, getting a lecture from my late grandfather, the gist of which was "never put a thread up dry".

Mind you, he was a marine engineer, so he was used to bolts a tad bigger than those on the average bike.

 

[steveindenmark]

I understand why some people lubricate threads, but it's not actually correct to do so.
Threads are designed to be employed "dry", and associated calculations (e.g. tightening torque) are based on this condition.
Just sayin'

I think you are correct. But with experience, you learn that a dab of copperslip makes life easier if you need to remove parts.

 

[RichardB]

I'm pretty sure that there is a difference between wet and dry torque values. In the automotive world, there is a presumption that torque settings apply to clean, dry threads, and there are sets of tables specifying how much to adjust torque values for various conditions of lubrication (grease, thread locker etc). The rule of thumb is that torque should be reduced by 20-25% if the thread is oiled. I have in the past stripped threads on a car or motorbike by using the 'correct' torque (using a calibrated torque wrench) on an oiled thread before I realised this.

I don't have links to back this up, by the way - it's just from memory, but it's stuck with me.

 

[Pat "5mph"]

Very interesting @RichardB.
So, what should we do about torquing greased bolts? Are there manufacturer's instructions?
I have recently acquired a torque wrench, just experimenting with it at the moment

 

[Smurfy]

I understand why some people lubricate threads, but it's not actually correct to do so.
Threads are designed to be employed "dry", and associated calculations (e.g. tightening torque) are based on this condition.
Just sayin'

Define "dry". Pretty much all fasteners will probably have oil residues on the threads left over from manufacturing processes, and I've yet to see an engineering fitting shop degreasing fasteners prior to assembly with torque wrenches.

And if you've noticed the number of threads pleading for help on seized pedals, seized freewheels, seized rack bolts etc etc, then lubricating threads is usually the correct thing to do, even if the lubricant is thread lock (which seals the threads and prevents moisture and corrosion).

 

[RichardB]

Very interesting @RichardB.
So, what should we do about torquing greased bolts? Are there manufacturer's instructions?
I have recently acquired a torque wrench, just experimenting with it at the moment

Well, as above, I would reduce the setting by about 20% - IF I were using a torque wrench on a bike. I have never done this - all my bike fasteners are tightened by hand to 'just right' and everything seems to stay put. I have no experience of carbon, but I understand that some torque settings are fairly critical. In that case, I would probably lube the thread (a general habit anyway) and under-torque it, and then keep an eye on it for any loosening. A regular check should prevent any disasters. Better that than over-torqueing and destroying something expensive I use a torque wrench (actually two, a small 'un and a big 'un) when I am working on cars or motorbikes, but it's usually only on critical components like engines or wheel nuts. Everything else is 'tight enough'.

Define "dry". Pretty much all fasteners will probably have oil residues on the threads left over from manufacturing processes, and I've yet to see an engineering fitting shop degreasing fasteners prior to assembly with torque wrenches.

And if you've noticed the number of threads pleading for help on seized pedals, seized freewheels, seized rack bolts etc etc, then lubricating threads is usually the correct thing to do, even if the lubricant is thread lock (which seals the threads and prevents moisture and corrosion).

To be honest, I lube (or threadlock) almost everything for this reason - although not car wheelnuts, where a bit of corrosion to keep them in place is not a bad thing. When I do use a torque wrench - which is only when it's required - I tend to go to the recommended settings and only under-torque where the risk is obvious (steel bolts into alloy engine cases being an obvious example).

 

[Pale Rider]

I seem to recall, some time around 1960, getting a lecture from my late grandfather, the gist of which was "never put a thread up dry".

Mind you, he was a marine engineer, so he was used to bolts a tad bigger than those on the average bike.

That's what a couple of former shipyard workers on Wearside told me - it was drummed into them, grease every thread.

Pedals will seize without grease, as will seatposts.

Applying 'engineering principles' to a bicycle doesn't always work.

My local bike manager shop told me he's had several customers over the years say: "I'm an engineer, so I know."

The usual reply is: "Fine mate, you get on with it."

 

[Oldfentiger]

I suppose if advice of a general nature is posted then an army of Internet experts will rock up and blow holes in it. Answer - carry on and do what you think is right.
@RichardB makes a good fist of explaining the effects of lubricant on torquing of threads.
I'm in total agreement that all engineering rules aren't the most appropriate for every single application, so those on a mission to prove my wrong can now breathe easy.

I recently rebuilt a BSA B40 engine, where I had to helicoil a dozen stripped engine casing threads. Aluminium housing threads, steel screws with fine thread, lubricant, and ham-fisted spannering led to inevitable conclusion.

 

[mickle]

Copaslip is evil sh!t. Keep it away from living things at all cost. Ideally by not using it at all.

Grease all threads with a high quality biodegradable grease such as White Lightening, wipe off the excess and sleep soundly in your bed.

 

[woohoo]

I recently rebuilt a BSA B40 engine, where I had to helicoil a dozen stripped engine casing threads. Aluminium housing threads, steel screws with fine thread, lubricant, and ham-fisted spannering led to inevitable conclusion.

Sounds a bit like the old Hillman Imp engine. When taking the cylinder head off that, I had my first experience of using the badly named "Easy Out" tool.

Anyway here are a couple of general links about greasing and its impact on torque settings
http://jthomaseng.com/the-effects-of-lubrication-on-fastener-torque
http://home.jtan.com/~joe/KIAT/kiat_2.htm

Personally, I do use anti-seize on some threads (and usually back off the torque a bit) but never on car wheel bolts which I always torque up dry.

(and "by feel", I find 5Nm for seat bolts to feel about right, 12Nm for chainring bolts feels OTT, 45Nm for cassette lock ring feels too high but 120Nm for car wheel bolts seems OK, so I guess, my own calibration is a bit suspect.)

 

[Julia9054]

Makes my fingers all glittery.
Everything's better with glitter.