Extra long end mills for milling foam

[FatFreddie]

Probably easier to make an extender - with 20mm dia you've plenty of room to hold a 1/4 inch shank 20mm router bit in a 19mm shaft.

[Jonathan]

Probably easier to make an extender - with 20mm dia you've plenty of room to hold a 1/4 inch shank 20mm router bit in a 19mm shaft.

That's a good way to do it, depending on how deep he needs to cut. If this cutter needs to cut the surface of a tall face perpendicular to the bed, then a cutter with long flutes will get a better finish.

[John McNamara]

Hi Gav

Be careful if you extend the shaft that you do not reach the "critical speed" at which point there will be greatly increased vibration. Particularly if you are using a Chinese high frequency spindle. that can push 20,000 RPM.

The shaft can bend to and suffer catastrophic failure. If it flies off and hits a person you can imagine the damage it could do.

Regards
John

[Bazzer]

Try searching for "frog tools " if I remember right, they do long foam bits. Not cheap tho !