In my view, more flutes will not reduce tearout nor do much for efficiency. All wings on the slotter should be on the same circle. Oddly, many cutters, when viewed in high speed strobe photos, show that only one flute is doing the cutting no matter how many there are! More on tearout at
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************************************************************************> While cutting some 1/4 dados in 9 ply 1/2" birch plywood for drawers,I experienced excessive splintering of many of the pieces. Especially
> on the bottom support of the dado.
>
> I ended up feeding backwards on the router table and this helped quite
> a large amount. Making smaller passes in opposite rotation direction
> did not make a difference.
>
> My cutter only has 2 flutes, do the 3 and 4 flute cutters stagger
> their distance from the center or just come by more often causing a
> less tramatic impact on the wood.
>
> Thanks
>
> Alan