Class of Hardware ? ( 8 or 10 )

[theiceman]

Hello All

During my Build I have bought a fair bit of hardware to renew. I see nuts and bolts etc are easy to get at my local supplier. I often see the exact same hardware in yellow zinc in Class 8 and Class 10 hardware.

I can not find any markings on the old stuff as to the property class . I have been going with Class 10 , well , coz I figure its a higher number so it has to be better

Got me wondering though does anyone know ?

Thanks

[prschmn]

metric 10 is fairly equivilant to and american grade 8--probably overkill for most needs.
Things like flywheel bolts etc. though-another matter.

[chris_seven]

All very much a muddle.

High Strength Metric Bolts have Grade 8.8, 10.9 and 12.9 and at least for Hexagon Bolts normally have marks on the heads.

I have never seen them specified as 8, 10 or 12 anywhere in Europe.

The lower strength grades such as 4.6, 4.8 and 5.8 are commonly sold without head markings.

Grade 8.8 Bolts are made from a material with a Tensile Strength of around 820MPa (125ksi) which would be equivalent to a Grade 5 UNF fastener.

Grade 10.9 is not very common (apart from Unbrako Durabolts) now and are made from materials with a Tensile Strength of around 1020 MPa (150ksi) which, as has been said is equivalent to a UNF Grade 8.

All of the trailing arm and torsion bar cover bolts used by Porsche were specified as Grade 10.9 although they are commonly replaced by Grade 8.8 but I am not keen to do this and buy bolts form Porsche.

Socket Cap Heads are typically Grade 12.9 and are a material with a Tensile Strength of 1220 MPa (180ksi) which is around the same as UNF Socket Cap Screws.


Flywheel bolts used to be made from a Grade 14.9 material but these are now very hard to find and often substituted for a Grade 12.9.

[theiceman]

Chris the nuts I was looking at were a metric grade 8 or 10 link below. I new you were the right guy to chime in . The bolts I saw were mostly 8.8

this is just a small example of the nuts .

Spaenaur Catalog 13 v1.4

http://www.spaenaur.com/catalog/#C33/z

http://www.spaenaur.com/catalog/#C34/z

[chris_seven]

I would agree that Metric Nuts are classified and Grade 8 or 10 - hardly ever 12.

I had overlooked this and just considered the bolts - should have thought more about this

I always tend to over specify fasteners and would tend to buy the Grade 10.

[theiceman]

ok thanks

Class 10 it is