Re: [ihc]knurling pistons was: David's "diesel" 258

["Jim or Ginger Aos" <jaos@xxxxxxxxxxxxxxxxx>]

----- Original Message ----- 
From: "Ryan Moore" <baradium@domain.elided>
To: "Jim or Ginger Aos" <jaos@domain.elided>; "John Hofstetter"
<hofs@domain.elided>; "ken.dunnington" <ken.dunnington@domain.elided>
Cc: "David Bongo" <dbongo@domain.elided>; <ihc@domain.elided>
Sent: Thursday, August 19, 2004 6:13 AM
Subject: Re: [ihc] Re: David's "diesel" 258


>
> ----- Original Message ----- 
> From: "Jim or Ginger Aos" <jaos@domain.elided>
> To: "John Hofstetter" <hofs@domain.elided>; "ken.dunnington"
> <ken.dunnington@domain.elided>
> Cc: "David Bongo" <dbongo@domain.elided>; <ihc@domain.elided>
> Sent: Thursday, August 19, 2004 00:43
> Subject: Re: [ihc] Re: David's "diesel" 258
>
>
> > ----- Original Message ----- 
> > From: "John Hofstetter" <hofs@domain.elided>
> > To
> > <Snip>
> > Anyone else on the digest old enough to have pulled out pistons and
> > > knurled them, put new rings on them and stuck them back in ?
> >
> >  Yup
> > Jim A.
> >
>
> I thought one of you "more experienced" types would realize this, but
> still... no one has explained what it means to "knurl" a piston.  Thus,
> those of us who are not as experienced may have no clue what you people
are
> talking abotu.

Think about the action of a chisel or a punch impressing a piece of metal.
Part of the chisel point penetrates, and part swells up along the edge.
That results in a larger o.d. in a very small area.
O a piston this was done on the skirts ( that part that helps keep the
piston aligned and resist wear from the fore and aft forces from the
crankshaft).  In stead of using chisels, a roller with sharp teeth was used
with a back and forth motion.  An internal system is / was used for loose
valve guides.  Another form of knurling is the bolts that have rolled
threads.  They also compress the thread area making it denser and stronger
than cut threads, eg. some head bolts, and some steering parts, like tie rod
ends.   Files are made with the impressing precess also, that's why the are
thicker on the cutting area than the rest.    Hope tht helps.
Jim A.
>
> -Ryan
>
>
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