3-flute versus 2-flute trim bit

[newood2]

Is one better than the other?
I'm looking to buy 1.5" cutting length trim bit from MLCS and they're pushing the 3-flute as a better bit.

[DaveW]

In theory, three cutting surfaces would spread the wear and tear and the bit would last longer (I think that's Dewalt's claim with their three-blade planer too).

Whether it's true or not, I don't know though.

[Russianwolf]

Not only does it cut down wear and tear, but it multiplies the number of cuts your getting. This results in each cut being smaller and finer which should equal a smoother surface.

[LCHIEN]

They're both right.

[Stytooner]

Not sure about three, but I know four is more desireable for an edge cut and two on a dado when talking about end mills. Not sure how that works, but its possibly due to the heat and vibration effects on the tool when buried. I use that priciple in woodworking too and it serves me well. Two flute for dados. More flutes if possible for edge cutting.

[drumpriest]

If this is for flush trim, then the best is the spiral, but I'd pick the 3 flute over the 2 for the reasons already stated. Higher cuts per minute mean smaller cuts being made, which should result in less tearout issues.