flywheel bolt hardness / grade

**rob** · 13-06-2007, 06:41 PM

i am getting some flywheel bolts from a supplier through work but dont know the hardness or grade for them as there is nothing stamped on them

does anyone know their specs?

is it worth the bother or should i just go get them from toyota?

**The Real Roadrunner** · 13-06-2007, 07:03 PM

the oem bolts are less likely to let the flywheel try to take your ankles off .
that being the case id spend the $10 a bolt

**mrshin** · 13-06-2007, 07:10 PM

They're a lot less than that for most bolts... I think the last ones I got were $2.something each.

**roadsailing** · 13-06-2007, 07:30 PM

just buy them from toyota, better than frigging around with something not designed for the task (not in terms of strength, but fit etc)

for example they could have a specific thickness shank, and they tend ot be quite short.

**rob** · 13-06-2007, 08:24 PM

yeah i have come to my senses, judgement was clouded by my tightness

ta

**clubagreenie** · 13-06-2007, 08:31 PM

If they're not marked I'd be dubious. I can remember which way it works but one end is higher shear strength and the other higher tensile strength. Of course I'm only talking normal grades 8/8.8 to 12 + (gde 5 = ftl) it could be shear to tensile or the opposite.

Then you need to consider the plain section of the bolt (if its threaded to the head then it's a screw) by both its thickness and length. Some are stamped and these are usually the thickness of the valleys of the thread, turned bolts/screws are usually thicker (thickness of the thread peaks). Length there is no standard ratio for but seems to depend on bolt size vs LOA.

**YelloRolla** · 13-06-2007, 11:53 PM

Originally Posted by clubagreenie

(if its threaded to the head then it's a screw)

For useless piece of information number 236 - a bolt that is threaded all the way is called a set bolt

**clubagreenie** · 14-06-2007, 07:21 AM

So whats a machine screw then?

Anyway you're net privledges only return when Ed's bits are finished

**The Real Roadrunner** · 14-06-2007, 08:23 AM

Originally Posted by clubagreenie

So whats a machine screw then?

Anyway you're net privledges only return when Ed's bits are finished

dude are you for real or what. ask him in a PM if you need lessons on engineering/machinist crap.

**clubagreenie** · 14-06-2007, 09:48 AM

Everything I've read/learnt has alluded to these being called machine screws. I have only heard of refs to bolts not set bolts, but have refs to set screws. Also socket screws in their various head types are referred to with full threads, but socket bolts have a plain section.

As for the last post, when I'm talking to you I will address you. I know when I need lessons, I don't think I'm above anyone until I know what they know, and as for Y/rolla, I know I don't know as much as he does, just I have worked in industry and specialised in procuring fasteners so I feel I have more than just a passing knowledge.

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