Tell what you know about... Fasteners, Grades, and Usages.

If, you are like me , then when it comes to buying nuts bolts, washers and even bearings, we end up paying way over the odds for these items because you buy Genuine parts simply because you don't know or can't interpret the markings on bolts and so we let others charge extra. Paying more and trusting to others.
Perhaps some one can share their knowledge?


Engineering grade nuts and bolts are marked as ?
Bearings fit for use on motorcycles are know by what signs and symbols?

US Bolts
Head Marking Grade and
Material Nominal Size Range
(inches) Mechanical Properties
Proof Load
(psi) Min. Yield Strength
(psi) Min. Tensile Strength
(psi)

No Markings
Grade 2
Low or medium carbon steel 1/4 thru 3/4 55,000 57,000 74,000
Over 3/4 thru 1-1/2 33,000 36,000 60,000

3 Radial Lines
Grade 5
Medium Carbon Steel, Quenched and Tempered 1/4 thru 1 85,000 92,000 120,000
Over 1 thru 1-1/2 74,000 81,000 105,000

6 Radial Lines
Grade 8
Medium Carbon Alloy Steel, Quenched and Tempered 1/4 thru 1-1/2 120,000 130,000 150,000
Stainless markings vary. Most stainless is non-magnetic
18-8 Stainless
Steel alloy with 17-19% Chromium and 8-13% Nickel All Sizes thru 1 20,000 Min. 65,000 Typical 65,000 Min. 100,000 – 150,000 Typical
Metric Bolts
Head Marking Class and
Material Nominal Size Range
(mm) Mechanical Properties
Proof Load
(MPa) Min. Yield Strength
(MPa) Min. Tensile Strength
(MPa)

Class 8.8
Medium Carbon Steel, Quenched and Tempered All Sizes below 16mm 580
640

800

16mm - 72mm 600 660 830

Class 10.9
Alloy Steel, Quenched and Tempered 5mm - 100mm 830
940

1040


Class 12.9
Alloy Steel, Quenched and Tempered 1.6mm - 100mm 970
1100

1220

Stainless markings vary. Most stainless is non-magnetic.
Usually stamped A-2.
A-2 Stainless
Steel alloy with 17- 19% Chromium and 8-13% Nickel All Sizes thru 20mm
210 Min.
450 Typical

500 Min.
700 Typical

Tensile Strength: The maximum load in tension (pulling apart) which a material can withstand before breaking or fracturing.

Yield Strength: The maximum load at which a material exhibits a specific permanent deformation

Proof Load: An axial tensile load which the product must withstand without evidence of any permanent set.

1MPa = 1N/mm2 = 145 pounds/inch2


Thats a good chart. There is no explanation of which strengths and what properties,are used for.

The Reuse of Fasteners

It was stated that the proof load represents the usable strength range of the fastener. By definition, the proof load is an applied tensile load the fastener can support without permanent deformation. The bolt will return to its original shape once the load is removed. The bolt may be reused provided you are absolutely certain the bolt never exceeded this point and began to yield: a simple enough definition, but one that requires an extensive explanation. As the fastened joint is put into use, it will encounter all types of various loads, including tension loads, shear loads, cyclic loads, prying loads and loads which may be a combination of these and other possibilities. Things like pressure changes in a pipeline, vibration from an engine or an impact of a hydraulic ram, may produce these loads. These external loads add to or subtract from the initial load of the fastener and in extreme cases may yield the fastener (refer back to the joint diagrams). Heat will lower the yield value of the fastener. The yield strengths are determined at room temperature. ASTM A193 B7 has a yield strength of 75-105 ksi (75 ksi for sizes over 4 inches in diameter and 105 ksi for material in diameters up to 2-1/2 inches) at 70 degrees, and drops to approximately 53-74 ksi at approximately 800 degrees. So, if we install a B7 fastener at room temperature expecting each fastener to support a tensile load of 85 ksi, which would not yield the fastener of diameters 2-1/2 inches and smaller. 28 Now, if we were to introduce heat into our fastener application, the fastener would begin to yield at much lower load. Was the fastener installed properly? This is one of the most difficult questions to answer (please refer to the section titled Tension Control in a Bolted Joint). This section discussed the difficulty of analyzing proper installation procedures. Extreme caution should always be used when relying on torque from a formula to indicate the tension induced. Torque is only an indirect indication of tension. Improper installation may yield the fastener.
One important factor to remember;
typically you will not know whether or not the fastener has been yielded.
Especially in critical situations, you should never reuse a fastener unless you are certain the fastener has never been yielded.
Re-use of Fasteners and Torque The basic function of the nut is to produce and maintain the clamp load on the assembly. As the fastener elongates, it starts to apply a compressive load to the nut. The first engaged thread of the bolt experiences an enormous amount of tension from the entire body. Some of this load is transferred to the nut causing less tension in the bolt at the second engaged thread. Then, this thread transfers part of this load to the third thread, and so on. The threads of the bolt will stretch. At the same time, the compressive forces acting on the bearing surface of the nut squeeze the bottom threads of the nut together.
Due to this deformation causing an uneven load distribution, the first few threads may plastically deform (yield).
The first few threads of the nut will support the majority of the load.
Research has shown in some cases involving UNC threaded nuts, the first thread will have to support nearly 35% of the load. The second thread will support about 25% of the load, and the third thread about 18%. To best allow the load to distribute to the mating threads, the nut is slightly softer that the bolt to allow its threads to distort a small amount to match the expanding contours of the bolt threads. If a nut were reused, there would no longer be a “perfect” thread match. This will create more friction between the threads during installation, which will significantly alter the installation torque. On a recent demonstration with a ½-13 zinc plated SAE J429 Grade 5 hex cap screw and zinc plated SAE J995 Grade 5 hex nut we used an installation torque of 70 ft-lbs to obtain a clamp load of 9000 lbs (without any added lubrication). On the second installation, this torque had increased to 95 ft-lbs to obtain 9000 lbs. By the fourth installation, we required 145 ft-lbs to reach a clamp load of 9000 lbs. Structural Bolts ASTM A325 & ASTM A490 are the two U.S. standard structural bolts. If you look at the mechanical requirements listed in the appendix, you may notice that an ASTM A325

My clutch casing, bolts are now three Nm's more than specified would replacing bolts help are they typically softer than casing?

So do motorcycle fastenings all fall within one specific grade (are grades that broad)?

Are bearings, colour coded or do they just come in different colours?

 

"Had a quick run through the link, say's it all really. What people forget is that the design engineer spec's a material, whether it's fasteners or anything really on its mechanical properties and suitability for purpose. The problems come when someone decides that the cost will be to high so they 'suggest' that the spec's are lowered to the minimum while maintaining safety standards. The poor unsuspecting punter who probably has no in depth experience of engineering design or mechanical engineering principles decides to replace items such as fasteners and innocently buys the wrong thing because they are easily baffled by the techno bull$#!t, it looks nice and shiny, or simply, they don't know any better, as in the case of my neighbour with the busted bolt who is a high school teacher, (and a bit of a pillock to boot). Forums like this are where the combined experience of many can be shared is such a great benefit to all."

cheers Sceptic still no sure how to "quote" so cut and pasted you .

 

ok I should wright is doon thank you

 

What Can I Do to Prevent Galling?
Slow Down Installation Speed
Because heat generated by friction is a contributing factor in galling, slowing down the installation speed can prevent galling. It is recommended thatpower tools not be used for the installation of stainless steel or other fasteners prone to galling. This is especially important when using nylon insert lock nuts as these nuts significantly increase the chance of galling.

Don't Use Bolts to Pull Joints Together
Bolts are not designed to pull together a joint or force materials into position. Doing so drastically increases the chance of galling. The materials being bolted should already be in place so the nut can be spun down by hand until the final tightening. If necessary, use clamps to hold the joint together during bolting.

Use a Lubricant
Special anti-seizing or anti-galling lubricants can be used to dramatically reduce the chance of galling. Examples include MRO Solutions 1000 Antiseize, Permatex® Anti-Seize Lubricant, Finish Line™ Anti-Seize Assembly Lube and USS Ultra Tef-Gel®.

Even a standard lubricant, such as WD-40®, can help reduce friction and prevent galling. Some nuts are available with a waxed finish to reduce the risk of galling.

Avoid Damaged or Dirty Threads
Check for damage to the threads of each bolt, especially bolts with fine thread. You should be able to put a standard nut on a bolt by hand. If not, it may indicate dented or damaged threads.

Also note that debris in the threads of a fastener can greatly increase the chances of galling. Always use clean parts.

Use Extra Care With Lock Nuts
Nylon insert lock nuts and, especially, prevailing torque nuts generate a large amount of friction and heat during installation. If you are experiencing galling problems, slow down installation speed or consider a different locking mechanism.

If a Fastener Begins to Bind: STOP
If a fastener begins to bind before you are actually tightening it down, stop immediately. Wait a minute or two to allow any heat to dissipate and then back the fastener off. Inspect the threads for damage and try again with a new nut.


An anti-seize lubricant can be very effective in preventing galling.


Do not use fasteners with damaged or dirty threads.


Stainless nylon insert lock nuts are especially prone to galling.


Why Fasteners Gall
Why Are Stainless Bolts Prone to Galling?
Stainless, aluminum, and titanium fasteners form thin protective oxide films on their exposed surfaces that prevent corrosion. In addition, this coating reduces friction and prevents direct metal to metal contact during fastening.

The protective oxide film can be rubbed or scraped off under the pressure and movement of the fastener being tightened. When this happens these relatively soft metals come into direct contact. Friction increases and the chance of galling increases significantly.

What Is Actually Happening?
Thread surfaces have microscopic high points that can rub together during fastening. In most cases this does not present a problem as the points slide over each other without damage.

Under certain conditions however, the surfaces will not slide past each other. The high points will then shear and lock together, greatly increasing friction and heat. As tightening continues the increased pressure results in more material being sheared off the threads. This cycle continues with even more shearing and locking until the threads are destroyed and the fastener will no longer turn in either direction.


Try a 6-point wrench or socket on your seized nut/bolt. Start by rocking the bolt by tightening then loosing, this may be all you need to break through the rust. Try and avoid 12-point wrenches and sockets as they likely to slip and strip the bolt head.

Another great tool I have found that is made by Irwin Tools is there Original Locking Wrench. Found here

http://www.irwin.com/tools/locking-tools/the-origi...

This tool has been a life saver for me! It has removed the worst brake bleeder screws I have seen! It works on rounded fasteners too. This beast can be tightened so much, that it will WARP the nut! These have been in my box now and will not be leaving any time soon! They have a parrot beak shaped jaw allowing 3 sides of contact without marring up the corners of a hex fastener! Neat, Isn't it??


someone on here (I think) said something about mole grips actually forcing the threads to distort with the pressure and you end up with 2 problems!

 

Bearings


The ABEC scale is an industry accepted standard for the tolerances of a ball bearing. It was developed by the Annular Bearing Engineering Committee (ABEC) of the American Bearing Manufacturers Association (ABMA). There are five classes from largest to smallest tolerances: 1, 3, 5, 7, and 9. The higher ABEC classes provide better precision,efficiency,[citation needed] and greater speed capabilities, but do not necessarily make the components spin faster.[1] The ABEC rating does not specify many other critical factors, such as smoothness of the rolling contact surfaces, ball precision or quality/type of steel used.

The bearing material is not specified in the ABEC grades. Bearings not conforming to at least ABEC 1 can not be classified as precision bearings as their tolerances are too loose.

The scale is designed to allow a user to make an informed decision about the type of bearing they are purchasing. High rated bearings are intended for precision applications like aircraft instruments or surgical equipment. Lower grades are intended for the vast majority of applications such as vehicles, mechanical hobbies, skates, skateboards, fishing reels and industrial machinery. High ABEC rated bearings allow optimal performance of critical applications requiring very high RPM and smooth operation.

ISO's equivalent standard is ISO 492.[2][3]


What does ABEC mean?
Bearings rated under the abec system are typically called ''precision bearings'', and they are rated with a number from 1 to 9, with the higher number assigned to bearings manufactured against a higher standard of precision.

Heres another guide


As a biker and seller of motorcycle bearings I may be a little biased in my personal opinion on where is best to buy your bearings and which brand is best with regard to quality and value. This is not without good reason and I will, however, try to give an honest appraisal of the aftermarket selection available and hopefully you'll be better prepared to navigate through the eBay bearing minefield.

I should also mention, I am an ex-RAF propulsion technician, qualified to HND level in Engineering, have spent 3 years in technical sales selling into manufacturing and spent 2 years working for a bearing sales company in junior management, this doesn't mean I'm a bearing expert in any sense but I have enough knowledge to give a rough guide and as there isn't one here on eBay yet I thought why not...

The most important factor when buying bearings for your bike is quality and, like most things, all wheel bearings are not the same. They follow the same rule as everything else, you get what you pay for..

Some brands have a very good reputation in the UK ie. RHP (now made by NSK), SKF, FAG, Koyo, NTN and NSK are all well established good quality brands, NSK, NTN and Koyo are typically used by motorcycle manufacturers and are an obvious choice when looking for replacement parts. It's important to know that these companies manufacture all over the world so whether they are made in England, Japan, South America, China or Poland they are made to the same quality standards. The same machinery is used, the same material standards, heat treatment processes and quality testing is maintained and so on. So the country of origin of the brand is more important than the country of manufacture. Some premium brands have manufacturing facilities in China and maintain their standards (and avoid Chinese steel suppliers!) but because of the reputation China has, and a fear of buyers jumping to conclusions about quality, they keep very quiet about this.

Some brands are made to a high standard but do not have much of a presence in the UK or even in Europe so the route of supply is not controlled in the same way as it is with the premium brands listed above, MTK (Belgian owned but made in China - Industrial Market), PFI (American owned South American made - Automotive Market) and KYK (Japanese owned - Automotive) are examples of brands that maintain good quality standards yet don't have much recognition in the UK. Importers are able to achieve better pricing because of the lack of distribution agreements in the UK, they simply can't buy the established premium brands directly.

The next category is Chinese, the Chinese domestic bearing market is huge, there are dozens of factories in China producing bearings and some of these, by western standards, are poor quality. Companies sprung up that buy and repackage these bearings for export and sell them around the world to distributors, they are of course super cheap. Brands include F&D, Challenge, WM1 & Zen or they come in unbranded. With these brands its always tricky to identify the factory location, Zen for example claims to be 'owned by a German family' on their website when they just have a distribution hub in Germany. UK Manufacturers, often trying to keep costs down, use these bearings in non critical applications. For example, if they are manufacturing conveyor systems then it's such a light duty application and they need so many of them that it makes sense to fit something cheap, if they're manufacturing a CNC programmable lathe, a more high speed application where the bearing is under a load, then they don't want bearing failure ruining their reputation. If they're manufacturing motorcycles then they don't want a wheel bearing to wear prematurely and create wobble, or even worse collapse completely and cause an accident. There's nothing wrong with these bearings being sold into industry and maybe some are better quality than others, the fact that they've worked their way into the motorcycle aftermarket spares industry is another matter.

So what makes them poor quality? the trouble is they are an unknown quantity, the steel grade and heat treatment process is an unknown, without carrying out independent testing its hard to say what levels of reliability and of course safety, can be relied upon in a motorcycle wheel. I wouldn't fit Chinese branded or unbranded bearings to my bike, partly because I know I would worry whilst riding and also the difference in cost is usually negligible, Ironically, no one begrudges putting £20 worth of fuel in their tank but they will fit Chinese bearings to their wheels permanently to save £5.00. It doesn't make much sense to skimp on these components but many hundreds of sets are fitted to bikes every year. The reason must be that there's a lack of awareness on the part of some consumers, if the seller lists an item as 'high quality' or 'made to ISO standards', they tend to believe it. The end result of this seems to be that peoples perception of a fair price has been changed and bearings are changed on motorcycles more regularly, just thank god for our MOT system.

I have to say there are exceptions to the rule, All Balls are a US owned company which has worked hard to achieve an acceptable automotive quality bearing from a Chinese factory through a Hong Kong export company called KML, this means they're cheap in the USA and perfectly safe to use, although widely acknowledged not to be of premium quality. They're expensive in the UK as they have to come through an extended supply chain so they aren't the logical choice unless you have little option, I do sell their swing arm kits though because the OEM manufactured kits are so expensive and the All Balls kits are actually quite good, some use PTFE coated washers which are an improvement over the standard set up. I've not heard of their steering bearings failing either.

I know there are plenty of riders who only fit the best to their pride and joy and research everything they do thoroughly, this is aimed more at people who are confused by the vast selection available out there and I hope this has been of some help,

Ride safe (stolen from ebay and redistributed to the poor)

 

MCN goes as far as to say always replace bearings with the exact same type. only how do I know, is it colour, or what does the writing on the bearing mean,
I can not seem to find a guide at all.

 

so is there a key or index of these numbers any where? (bearings)

Iim cutting and pasting Col C's post on here as I would like to collect and collate a gulde.

Yes, the number tells you the tensile strength of the bolt, for stainless this is nearly always -70 which means it has an ultimate tensile strength of 700MPa (or N/mm²). -80 are not usually stocked, they can be bought but usually to order, you can get even stronger but you'd probably have to order in the hundreds or thousands. Stainless screws are not as strong when compared to most carbon steel screw you'll find on bikes/cars. *1

e.g. 8.8 bolt - the first number relates to UTS (800MPa), the second to percentage of UTS that the screw yields at (80%). So a 12.9 high tensile screw will fail at 1200MPa and will start to yield at 90% of that.


The A number in stainless screws signifies the chemical composition, I've only ever come across A2 and A4. A2 is a 304 type stainless, A4 is 316.
Unless you live on a harbour wall or make a habit of riding on gritted roads I would suggest A4 is perhaps over-kill for bikes (but does no harm as it has nothing to do with the screw strength), A2-70 should be fine for low stressed applications (engine covers, bar clamps, brake levers, etc.)
Next time you're on the ferry look at the fasteners, you'll see A4-70 used everywhere. (sad anorak, pass the time looking at screws when I should be in the bar.)
On items like brake disks and calipers I would stick with the manufacturers fasteners, they're likely to be high tensile and often a special form in any case.
My experience is that fasteners on Hinkley Triumphs are above average for the sector and use stainless quite extensively as standard, so usually no need to change.
I defected to Ducati for a couple of years, their fasteners and fittings (e.g. brake line banjo ends) are definitely inferior.

*1
Ultimate tensile strength (UTS), often shortened to tensile strength (TS) or ultimate strength,[1][2] is the capacity of a material or structure to withstand loads tending to elongate, as opposed to compressive strength, which withstands loads tending to reduce size. In other words, tensile strength resists tension (being pulled apart), whereas compressive strength resists compression (being pushed together). Ultimate tensile strength is measured by the maximum stress that a material can withstand while being stretched or pulled before breaking. In the study of strength of materials, tensile strength, compressive strength, and shear strength can be analyzed independently.

The UTS is a common engineering parameter when designing brittle members, because there is no yield point

Thank you Col C

 

So because the threads are part of the block and although they have been stretched slightly they can-not be changed.
if I replace the casing bolts for new OEM bolts am I doing more good than harm or vice versa.
Is it better to stay with the matching set as it were, or would replacing half the threads with new (if u c what I mean) be a more ideal solution to my stretching threads?

 

tried to find skf site, have now earned a yellow belt in karate.
could you post a link please Col C

 

excellent man, thank you. Im off to the shed to get an old bearing.