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Amen, amen, amen, brothers and sisters !!! also,..heat treating has some effect,...and ultimate yield strength will depend on the care and characteristic of the thread ROLL ( as opposed to cut) JC On Mon, 13 Dec 1999 08:05:48 -0500 shammar@nsk-corp.com writes: > > That's interesting. Was that a tensile test for ultimate strength? > How about > stiffness or torsional strength? It raises an interesting question > since the > main function of the stud will be to apply the greatest clamp load > possible and > maintain it. The only way to increase the clamp load is by > increasing the > torque on the fastener to further preload it, but a material strong > enough to > handle that torque without yielding throughout the operating > temperature range > is necessary. The only way to appreciably increase the stiffness of > the stud is > to increase it's x-sectional area (diameter), since Young's modulus > is virtually > the same for all steel alloys. The stock studs on the Kaws are > necked down near > the threads to match the thread root diameter. This may not be the > way to go > since multiple threads share the load, but the reduced necked area > must support > it. The aftermarket studs don't have that feature. > > Still, it's not totally clear cut and your friend's data is worth > considering. > It's funny that often we get sucked into replacing parts, assuming > that the > aftermarket parts are going to be better. It's tough to beat the > design, > manufacturing expertise, and quality of material source of a major > manufacturer, > and unless the new part is significantly different AND is done > properly, it is > often a step backwards. Pistons, rods, etc. often fall under this > category. > Ever have poorly machined pin bores or ring grooves on aftermarket > parts? I > have. Ever see it on stock stuff? No. I've taken a look at a few > aftermarket > wrist pins under the microscope and just about shit - they would be > cause for > shutting a plant down if we ground something like that. > > Buyers beware. > > Regards, > Bob > > > > > > > "Lorcan Parnell" <lorcan@mail.globalnet.co.uk> on 12/13/99 07:36:29 > AM > > To: Bob Shammas/EQA/Nsk-Corp@Nsk-Corp > cc: > Fax to: > Subject: Re: [turbobike] head studs > > > > Just as an aside to this a friend of mine who runs a 7-second CBX > funnybike > had some aftermarket studs tested and found that they weren't any > stronger > than the standard Honda ones (which he had never had any trouble > with > anyway). > > Regards > > Lorcan > > > > >