use of flat head bolts ?

[kris29]

Hey guys...

in our design the bolts we are using for sprocket mount are clashing with differential mount , so we are thinking of using flat head bolts in sprocket mount . so please
guide if we can use flat head bolts here or not ?

[Z]

Hey guys...
.. so we are thinking of using flat head bolts in sprocket mount...

Kris29,

I have just had a look in my Great-Big-Box-Of-Miscellaneous-Bolts, and ...
... they ALL have flat heads!!!

Well, most have some embossed numbers or symbols on them, but otherwise the heads are FLAT.

If you want a better answer, then you had better ask the question more clearly.

Or maybe post a picture of the bolts you want to use.

Z

[Unhealthy_FSAE_Addiction]

Z, these are flat head bolts

http://www.genright.com/images/products/FlatHeadBolt_sm.jpg

Didn't your uni teach you about fasteners?

[Unhealthy_FSAE_Addiction]

T11.1 Fastener Grade Requirements
T11.1.1 All threaded fasteners utilized in the driver’s cell structure, and the steering, braking, driver’s harness and suspension systems must meet or exceed, SAE Grade 5, Metric Grade 8.8 and/or AN/MS specifications.

T11.1.2 The use of button head cap, pan head, flat head or round head screws or bolts in critical locations is prohibited. These locations include the driver’s cell structure, and driver’s harness attachment

See this discussion:

http://forums.sae.org/access/dispatch.cgi/fsae_pf/docProfile/100178/d20081029213418/No/B.14.2.1%20Redundant%20Fasteners

I don't see driveline explicitly mentioned as a location in any of these discussions, so perhaps you could technically use flat head bolts. You should probably clarify with SAE though. I don't often see flat head bolts used in shear.

Edit: Similar discussion of flat head bolts used on a brake rotor. The rules committee found the location to be 'critical'

http://www.fsae.com/forums/showthread.php?6638-Countersunk-Cap-Screw-Critical-Fasteners&

[Z]

Z,
...
Didn't your uni teach you about fasteners?

Unhealthy,

In all of the drawing offices I have worked in, all around the world, any draughtsman specifying a "Countersunk Socket Screw" as a "flat head bolt" would very quickly be out on the street.

But nowadays I guess it is all about, "Err..., ummm..., whatever... (they'll know what I mean...)........"

Z

(Edit: It seems that the US is leading the way in calling a COUNTERSUNK SS a "flat head bolt", even though its "flat-headedness" is its LEAST distinguishing feature!)

[Drew Price]

Unhealthy, I think Z was trying to get the original poster to be more specific, as his question was extremely vague and didn't express why he thought his solution was or was not ok.


***************

Z,

It's possibly a US thing - they are sometimes called that in fastener catalogs, but we are usually taught that they are countersunk socket screws.

My first thought was that the original poster meant these (we call that a flathead screwdriver, rather than a blade or flat-blade screwdriver):

http://ecx.images-amazon.com/images/I/41cPtsYuUWL._SL500_AA300_.jpg

[Big Bird]

Flathead bolt? That is one with a fillets head, right?

Kris, I hope you are herring where we are coming from, and no-one’s baiting you on porpoise. But sometimes, we just feel like we just keep re-inventing the whale. There are many who surf through this plaice angling for a free ride, and we are full to the bream. Sorry to carp on about this, but we hope that one day, buoys and gills, that you might tackle your problem and mullet over before chasing us for a batter answer.

Remember, cod helps those who kelp themselves.

And for cod’s hake Z, stop being so shellfish, get back on your perch and give salmon else a go. You just bait people for the halibut. Its giving me a screaming haddock. ;)

Anyway, if I can help at all, plaice let minnow.

Sea y’all later,

[kris29]

I wanted to ask you all if you guys consider sprocket in a critical location or not because using flat head fasteners in critical locations is strictly prohibited. Rules do not provide a clarification for the same.

[Drew Price]

Do you think the fasteners holding the sprocket on have to meet rule T11.1.1 and T11.1.2?

That is what we are trying to get you to figure out on your own, it's pretty clearly spelled out in those two rules.

[Big Bird]

Hi Kris,

As soon as I see a rule outlawing something like a certain kind of bolt in "critical locations", I avoid that kind of bolt everywhere. You don't want to be arguing interpretations with scrutineers at comp, or rebuilding your car on comp Friday/Saturday.

Only the rules committee can answer your question absolutely. This is just a forum full of opinions. My opinion is to avoid them, and thus the risk of rejection at comp.

Cheers,

Geoff

[jd74914]

As soon as I see a rule outlawing something like a certain kind of bolt in "critical locations", I avoid that kind of bolt everywhere. You don't want to be arguing interpretations with scrutineers at comp, or rebuilding your car on comp Friday/Saturday.


This is our general rule. Why push something so inconsequential, especially if you might need some "goodwill" for other grievances.

[Michael Royce]

Unhealthy,
Glad to see someone is still using those "old" FAQ's! Most are still applicable.