Stainless Steel Fasteners

[Boxadog 2000]

For those of you who are interested and for those that can stay awake to the end of this post.
this information comes from a company called Fabory who are major manufacturers of fasteners in Europe.

Stainless Steel Mechanical Properties.
Property classes 50 70 80
1 System of designation of property classes.
A characteristic property of austenitic stainless stell is that-contrary to the heat treated steels which are used for the property classes 8.8,10.9 and 12.9-this material cannot be hardened and tempered, but can only be strengthened by cold working, increasing the mechanical properties considerably.
the 3 austenitic stainless steel grades A1,A2 and A4 are divided into 3 property classes 50,70 & 80 depending on the method of manufacturing and on sizes. The number of the property class corresponds with 1/10 of the tensile strength in N/mm2, eg class 80 has a minimum tensile strength 80 x 10 = 800N/mm2.

50 = the soft condition of turned and hot pressed fasteners. this is seldom used for current fasteners.

70 = the most universal and applied property class for all cold-formed fasteners this is the standard class and is delivered when no other class is ordered.

80 = the highest property class having obtained mechanical values by extra cold deformation to the level of the 8.8 heat treated steel bolts.

The following information is not from Fabory.

So as I understand it if you can get class 80 st steel this is approximatley equal to 8.8 grade steel which is standard high tensile strength this however is not as strong as standard steel capscrews which are 12.9 grade.

As an example a 12.9 grade 8mm steel capscrew would take 28,000 newtons to break.


A 8.8 grade steel capscrew would take 16,000 newtons to break.
So if you use grade 80 stailess steel it is aproximatley half as strong as 12.9 steel.

Bored yet!
In all of my BMW bikes 3 air heads 3 Ks and the 1100s iI have always used standard A2 on all applications this includes disc bolts pinch bolts clamp bolts in fact every bolt application on all of the bikes and i reckon that I have covered well over 200,000 miles in the 27 years that I have owned Beemers.
So the kit that Rob can get will be just fine for all applications, but remember you use it at your own risk as I do.

You may now wake up and read something usefull.

Bob

[Gromit]

Bob - that's a very informative post.

If a muso like me can understand it anyone can

[minivin]

<raises head from Standard Integrals and second moments of area course work>

Excellent work, cheers for that Bob