[Andre' B]

They make necked endmills, where the shank diameter is slightly smaller than the cutting diameter... Bosch makes a 1/2" router bit with 3"+ flutes (I have one). Personally, I'd try and use or find a bit that will cut the full thickness of your work if possible...

The main reason for a necked endmill is that a 1/2" tool with 0.500" of flutes and 2.5" of neck that is 0.495" is a lot more ridged then a 1/2" tool with 3" of flutes.
Used a lot in milling molds, customers always seem to design things so we have to reach deep into small places.

[BanduraMaker]

I broke down and bought the tool in Ger's link - hence my wife's nasty looks in his direction.

I don't think that sanding would have been very dangerous to be honest though. I wouldn't be holding the sandpaper against the bit but rather doing it "shoe shine" fashion. If it got torn away, no big deal. Effectiveness is another matter.

I think that with a 5" OAL, I should be able to clear the stock without too much difficulty.

Thanks guys.