Nuts And Bolts

[nelmo]

Continuing my education (I have no formal engineering experience or qualifications), I have a few basic questions, if you don't mind:

 

1. I bought a set of mixed nuts, bolts and washers. The washers are spring washers - are these OK to use where you would use flat washers or are they for a specific purpose only?

 

2. Is a nyloc nut as good as using thread lock on a normal nut? Or are they each for a specific purpose?

 

3. Is there a bolt material that is best to use or is it dependent on application?

 

Thanks for any advice.

[Guest mcramsay]

Normally you would put a flat washer under the spring washer otherwise the spring will scratch the panel when you tighten it, spring washers are used to stop nuts undoing them selfs under vibration.

 

Nyloc nuts are good to use and look professional and just as good as basic thread lock( there are loads of different thread lock types) however nylon nuts should not be reused.

 

Material is down the the application, personally I use stainless as it won't rust,

[Guest 2b cruising]

Another couple of important points to note.

Cheap flat washers are usually so thin they are hardly fit for purpose. Especially on higher torque requirements.

Never use thread lock on direct aluminium components, unless steel thread inserts, "not the helicoil type" have been fitted by the manufacturer. Failure to comply will most likely end up stripping the aluminium thread out of the component, when the bolt or stud is required to be undone.

Ensure spring washers are strong enough to take the required torque without spreading. If they spread out from under the fixing they are doing nothing.

 

Here endeth the lesson. LoL

[nelmo]

Hmm, thank you all - so is there a standard for washers and bolts? Some markings I should be looking for? How thin is too thin?

 

For example, my master brake cylinder arrived without fittings. I'd already decided to put a flat washer behind the spring washer but the bolt from my (probably rubbish) set is black. I'm not sure if that is a coating or just some cruddy material. I'm guessing it might not be an issue for the brake cylinder as it doesn't seem to be a high-stress area, or is that codswallop?

[Guest 2b cruising]

Black is good.

There should be a number on the bolt head. 8 and above is hard so no problems for that job.

Hard bolts can really be used on anything. It's just the expense of them.

Others are marked with a ring system but unfortunately I never took enough interest to study this.

Stainless have different markings again.

No marks usually means standard fixings.

Washer problems never used to occur prior to stores such as screwfix. They have to make them cheaper somehow.

The m/cyl job can be done with soft stuf though as no real pressure is felt at those points.

Even manufacturers of high end cars use standard nuts and bolts for them.

More care should be taken when fixing thins like steering, suspension, seat belt anchors, brake calipers etc.

When the term standard has been used, it only refers to steel fixings.

I think the IVA regs state what hardness of fixings should be on different components.

[nelmo]

Great, thanks.

 

Coincidentally, a new Screwfix is opening this weekend near me with a 10% off everything offer. I was planning on going - would you advise against there stuff?

[Guest 2b cruising]

Nut at all. Cough.

They do good stuff as well as bad stuff.

Study the catalogue before you but.

All details will be given, ie hardness of bolts, thickness of washers etc.

 

On washers of 10mm or over, 1 mm would be ok far washers.

Above 12mm a thicker washer would be better.

As in antiques, quality comes first. Especially with your own pride and joy.

[nelmo]

OK, thank you all - very helpful :-)

[knights_templar]

nothing to do with what is perfectly OK, just what the IVA will look for.

 

8.8 or above on everything.

 

yes there are degrees of strength allowed to fasten non structural parts together, that is a judgement for the tester, if it is 8.8 there is no argument, stainless is A2-7, imperial three lines. there are bolts on a Zero that are imperial.

 

IVA requires "visible locking device", nylock, spring washer but NOT with flat washer, and yes they damage the surface of the part they are used on, best not used at all, snar washer less damage much better device, philidas nut.

 

Lock tight is not visible, so bolts fitted with it should be marked as such, you may be asked to prove it.

 

8.8 on zero master cylinder is vital, as is larger washer due to adjuster slot, lock nut.

[nelmo]

spring washer but NOT with flat washer, and yes they damage the surface of the part they are used on, best not used at all, snar washer less damage much better device, philidas nut

 

Any reason why you shouldn't use a flat washer under a spring?

 

Is 'snar' a typo? Did you mean 'snap' or something else?

[cb750]

Probably means star washer - autocorrect strikes again! If you put a washer under a spring washer it stops the spring washer from digging in to the part and locking the nut to the part. You are then relying on the spring tension pushing against the washer and the back of the nut to stop the nut from turning

[Bob Tucker]

I always Namrick.

this may help....

https://www.namrick.co.uk/acatalog/tech-info.html

[knights_templar]

no not auto correct just the fact I have never seen their name in print so spelt it as verbally told to me

 

quick google

 

they are Schnorr safety lock washers type S. http://www.shop4fasteners.co.uk/washers/schnorr-safety-lock-washers/schnorr-safety-lock-washers-type-s-self-colour/c-24/p-197

 

appear to do minimal damage, look far better when fitted than a normal spring type

[Guest 2b cruising]

It is possible to get flanged nuts and bolts of the same style as the washers.

It saves a lot of messing about and they really are good.

When they have been on tight for a while, they can be very tight to remove, so I always use a six sided socket set.

Never ever had one come loose on me yet. Some manufacturers use them on all important parts. Especially on smaller fixings.

ie, diesel injector electronic connections tightened to only 4nm, and they are fitted under the cam covers. Vibration must be intense, but they don't loosen. They recon around 2nm overnight will pull the terminal out of the injector.

Info only.

[cb750]

Yes, they are good. I usually keep a few m6, 8, and 10 in both 8.8 and stainless A2/A4 grade just in case they are needed