Steering Fasteners

[erwinviking]

The rules read that threaded fasteners in the steering must be grade 5 or above. This seems to be a rule regarding bolts with tensile loads. Would a bolt only subjected to shear loading fastening the joints of the steering shaft need to meet this requirement also?

I am looking at using and airframe bolt as is suggestested by Pegasus for an apex joint but I don't see any grade listing for the bolt. Does anyone know what the grade of these bolts would be?

[erwinviking]

The rules read that threaded fasteners in the steering must be grade 5 or above. This seems to be a rule regarding bolts with tensile loads. Would a bolt only subjected to shear loading fastening the joints of the steering shaft need to meet this requirement also?

I am looking at using and airframe bolt as is suggestested by Pegasus for an apex joint but I don't see any grade listing for the bolt. Does anyone know what the grade of these bolts would be?

[Dan B]

What is the Yield and Ultimate tensile strength for an SAE Grade 5 bolt? If you don't know these off the top of your head look them up in one of your text books or online. Then look up the spec's for whatever bolt you want to use and see how they compare. Finding the spec for an airframe bolt should be easy to find. To give you some help because your google-fu seems weak start with a search for "an3-an20".

[Bazanaius]

NB you shouldn't be loading bolts in shear. For a start, often there is clearance in your hole to allow you to assemble it and so there will be associated relative movement between your parts before the bolt even offers any resistance.

Ideally you would prevent sliding movement by another method, but if not your bolt should be rated so that you can clamp the parts together with a large enough force for the friction between them to react the shear force without the bolt yielding in tension.

[fixitmattman]

Rule is indifferent to the type of loading. All fasteners must be minimum grade 5.

[BuckeyeEngines]

For those U joints the proper way to fasten it is with a taper pin. They can be found on aircraft spruce. Dont forget to get a taper reem. It sounds like that may be what you've already got, but in case you don't its what you need to meet the less than 7 degrees of play in the steering wheel rule.

[Adambomb]

AN bolts (guessing that's what they mean by "airframe bolts?") are pretty close to Grade 8. Grade 5 is the lightest "real" bolt class IMO. The only things lesser than that you're likely to encounter is the type of cracker jack box BS that comes in those bulk bolt/screw sets you get from K-Mart or with a coffee table kit.

I think I remember seeing the one Pegasus recommended...thinking it was a standard AN bolt, and came recommended with their little caps to go over round tubing. Personally I'd pick the taper pin over that. We used to use some sort of clamp-down conglomeration that worked OK, but this year we're going with a taper pin.

Also, if you plan on getting serious with FSAE, you're going to need an intimate knowledge of fasteners and other hardware. Carroll Smith had a good book on hardware. I believe his original title for it was "Screw to Win!" http://fsae.com/groupee_common/emoticons/icon_biggrin.gif