Head Bolts

Post by **500bernie** » Thu Apr 21, 2011 8:55 am

A technical question for all of you mechanical geniuses out there....

If I wanted to replace the head bolts with a stainless steel replacement

, what grade/specification stainless steel would they need to be made of to match/exceed the specification of the standard high tensile steel bolts?

Cheers,

Bernie

SP_BOTT · Post by **SP_BOTT** » Thu Apr 21, 2011 4:12 pm

As far as I know, no stainless is going to be as 'hard' as high tensile, standard 'over the counter' stainless fittings are A2 and the harderr versions is A4 (stamped on the bolt heads) both these are softer than 8.8 high tensile, (ie your head bolts) and Allen bolts are higher still, at 12.9 hardness.

I'm no expert, just what I'm lead to believe.

Bit boring, but shows a few examples
http://autonopedia.org/crafts_and_techn ... kings.html

Post by **500bernie** » Sat Apr 23, 2011 1:38 am

Thanks for the info....
Black high tensile it is then!
Cheers
Bernie

scooble · Post by **scooble** » Sun Apr 24, 2011 8:21 am

my bike is currently down the machine shop, therefore can anyone tell me what the dimensions are for the standard head bolts so I can find alternate replacements

Post by **500bernie** » Sun Apr 24, 2011 8:46 pm

Hi Scooble,
8x40
Cheers,
Bernie

scooble · Post by **scooble** » Tue Apr 26, 2011 5:22 pm

is that M8 1.25 or M8 1.5?

Tel · Post by **Tel** » Tue Apr 26, 2011 5:33 pm

On the subject of thread sizes/pitches, is there a list of bolt thread pitch sizes anywhere?

Tel

JanBros · Post by **JanBros** » Tue Apr 26, 2011 10:55 pm

standard M8 scooble, so it's 1.25