Re: mail Digest for 20 Feb 2005 in hour 0:00
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Re: mail Digest for 20 Feb 2005 in hour 0:00



remove my name from list please


--- "mail@xxxxxxxxxxxx" <List@xxxxxxxxxxxx> wrote:

> Topics covered in this issue include:
> 
>     1: Rolled fillet cranks
>               by "Bruce Hevner"
> <scramblr@xxxxxxxxxxx>
>     2: nitriding by the pound from KustomKemps
>               by lynn peterson
> <kustomkemps@xxxxxxxxx>
> 
> 
>
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> 1                                Message:0001       
>                     1
>
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> 
> Message-Id:
> <3rr0ks$it15k9@xxxxxxxxxxxxxxxxxxxxxxxxxxxx>
> From: "Bruce Hevner" <scramblr@xxxxxxxxxxx>
> To: "AMC AMC" <mail@xxxxxxxxxxxx>
> Subject: Rolled fillet cranks
> Date: Sat, 19 Feb 2005 22:25:55 -0500
> 
> >Another question is of fillet rolling - something
> >done to the Turbo Buick Grand National Crankshafts
> >to ward off cracks forming.   As I understand -
> these
> >filletts are rolled under high pressure during
> manufacturer -
> >is it possible to do this to welded up cranks  and 
> >cast crankshafts alike ?
> Rolling the fillets is not done to prevent cracking
> although it does kinda
> have that effect. It's done to increase the strength
> of the journal by
> effectively increasing and smoothing the radius of
> the area where the
> journal meets the crank itself AND compressing the
> metal at that point to
> make it stronger. We have been told to NEVER grind a
> rolled radius crank
> enough to remove (or even TOUCH) the radius. I
> believe the number given was
> a 20% reduction in strength. This means most of
> these type cranks will only
> grind .010 or .020 at most.
>  There are MANY OE cranks besides the Buick that use
> this. The later model
> Chebby cranks are rolled on the rear main only. I
> race a lot of Toyota 20r
> series motors. The rods are rolled on all these
> motors from the factory.
>  I have not seen this done in person but the
> pictures of the process I have
> seen involve a LARGE hydraulic press with narrow
> steel wheels rolling the
> journals of the crank. Not something the average
> shop could afford much less
> an individual.
>  We looked at having the cranks cryogenically
> treated to increase strength
> but it was pretty costly so we never had it done.
>  That is a REAL good indicator of quality in a crank
> grind. Forget the
> finish (look at it second),,, look at the fillets
> first!! Look at the
> fillets on a custom crank like COLA. They are large
> and smooth,,,
> BEAUTIFUL!! Sometimes it is necessary to trim the
> edge of the bearing to
> clear the radius on these cranks. 
>  If the crank grinder is lazy or they don't own a
> radius dresser for their
> machine, the radius will end up with a square
> corner. Do NOT accept a job
> like this!! It's a stress riser that INVITES
> cracks!!. The radius MUST be
> blended as perfectly as possible into the cheek of
> the crank. I have
> magnafluxed cranks where the crack was on the SIDE
> of the radius. The radius
> withstood the pressure but it was transferred to the
> mating line of the
> radius to the crank. Strange pressures are at work
> here!!
> But hey,,, that's just me!!
> Bruce Hevner
> 
> 
> 
> 
>
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> 2                                Message:0002       
>                     2
>
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> 
> Message-ID:
> <20050220060055.36478.qmail@xxxxxxxxxxxxxxxxxxxxxxx>
> Date: Sat, 19 Feb 2005 22:00:55 -0800 (PST)
> From: lynn peterson <kustomkemps@xxxxxxxxx>
> Subject: nitriding by the pound from KustomKemps
> To: mail@xxxxxxxxxxxx
> 
> Well, I'm glad to see that I have generated some
> chatter accross the ether. Some people think that
> nitriding is super expensive, but it is not. In
> fact,
> we nitride BY THE POUND, with a 100lb. minimum.
> Therefore, the more cranks we have in a run, the
> cheaper it is. Example: if you sent a crank from
> Ohio
> to the shop in Portland, Or, and did not have a UPS
> account, it would run about $170 to ship the crank
> both ways. (We prefer Forward Air) This is more than
> $100 over the cost of the nitriding. Except for one
> engine, all the motors we build run offset ground 2"
> SBC journals with a couple of 1.88" NASCAR size
> thrown
> in. The possibility exists that we could have a
> crank
> that is harder in one area than another. We feel
> that
> any crank that might be cut beyond the factory
> hardness level will be better for the process. (does
> anyone know what depth the AMC cranks were hardened
> to
> from the factory?_
> 
> L. Peterson 
> 
> Kustom Kemps
> 
> 
> 		
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> 
> 
> End of digest for 20 Feb 2005, hour 0:00
> ****************************************
> 
> 
> 
> 
> 



		
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