Originally Posted by Mike Kuttschrutter
oh, I got my info from here.....

http://www.dsmtuners.com/forums/articles-engine-fuel/303225-engine-machine-work-explained.html


"Another machine is the surface grinder, not a bad machine, it keeps the head leveled and indexed, it uses segmented stones. The surface finish is not smooth enough most of the time for MLS gaskets, The finish is dependent on what stones, how well dressed they are, spindle speed and table speed. Still very common in shops

The new boy on the block is a High speed Milling machine, these use a .500 (1/2) inch insert, CBN for cast Iron and CBN for alum. for the most part, as far I as know, have been around about 10 years. smaller shops are slow on getting them due to there cost, But without a doubt give the best surface finish. Some machines, Like the comec I use, have variable rate spindle speed and variable rate table feed rates. This will alow for diffrent surface finishes for diffrent gaskets"


No automotive machine shop is going to have a high speed machining CNC to use for surface finishing. Take internet info for a grain a salt. That info above isn't the greatest.

CBN is the next hardest material to diamond. There doing something right if there at least using that. But it all comes down to care and preperation for the finish out come. Just let them know that your concerned about the surface quality and will be checking upon pick up. Usually thats enough to get the guy to put extra care into the quality.

I have an ANSI surface panel sample to compare to judge the surface quality.

I wrote a huge paper in university on surface finish so its a bit of my expertise smile Ra isn't all it cracked up to be.


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