Quote Originally Posted by GeorgeD View Post
The thing is....carbide is for hardened steel and HSS should last pretty well for plastics and wood so whats the use in buying a more expensive endmill if thats all its cutting? providing the cut is in stages and not too deep each pass they should be up to the job.

Its the same with normal wood router bits,the more passes you use the less chance of the bit burning out in a short time.

Not quite true George, although they are softer than steel, some materials are very abrasive and will eat HSS is short order, Tufnol is a plastic but believe me a carbide cutter will outlast 7 or 8 HSS ones.

Printed circuit board is another, on a decent sized board you will be lucky if one HSS isn't burnt out at the end and it not all about deep or aggressive cuts.

When cutting softer materials the trick is to get the chips away to stop secondary cutting and clogging, this is where single flute cutters score as they have the most clearance of any cutter and most single flute cutters these days are carbide.