Re: Porting and relieving

[fly4scout@domain.elided (mike d ryan)]

>>- - Purchase of grinding bits to port heads and intake                
>     
>>             $45 ish
>
>Mike,
>John L. and I were talking the other night about porting and 
>relieving, and I used to do a fair amount of this years back, but I
haven't done 
>any in years. 
>
>We were wondering if a person could use carbide cutters in a die 
>grinder to speed up the process, rather than just use a variety of
grinding 
>wheels and points?
>
>John H.

John, 
	Carbide cutters in a die grinder was ALL I used for my porting.  They
cut fast at first, but it took two days to finish.  I used up 3 different
size cutters on these incredibly hard cast heads.  If I had purchased
replacement cutters and switched half way through the process, the time
would have been cut down considerably.  The cutters cut painfully slow
towards the end of the job.

	As for polishing, I used the carbide cutters for that to.  It takes a
steady hand, VERY light touch, and constant motion to give the metal a
smooth finish.  It's not as smooth as using grinding stones or pads, but
smooth enough for the RPM,s an IH will run.  The single cut bits gave a
smoother finish than the double cut bits.  The bit I used the most was a
6" shaft 1/2" cylindrical shape ball nose.  For the corners, a bit of
5/16" or 1/4" is best.  I couldn't find any flame shaped bits around, but
I think they would have been handy to have.  The bits with a sharp edge
at the top or bottom caused me problems.  The sharp edge digs into the
metal and leaves a ledge that would cause airflow turbulence.  If you
aren't perfect with bits that have all rounded edges, it's not a big
deal.  You might have a little dip in the metal, but the air will still
flow smoothly.

Take care,
Mike Ryan
1977 Scout II, 304 (soon ported 345), automatic, Dana 300, 3.54 gears,
4" superlift springs, 1.25" body lift, 33 X 12.5 Swamper TSL Radials

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