I do use incremental sizes up to 1 1/2" of both spade and forstner bits
along with a stout extender to open the hole and set the depth before
using arm rest and an inserted _cutting_ bit.

Most bit shaft extenders are flimsy and the more robust spindle
extenders extend the chuck which if the hole is big enough for it to
enter you _may_ not need the extender. Or as Yogi said, "If you don't
have it, that's why you need it!".

I would think in a home shop set up, the torque on 5 to 6 in. and larger
augers, saw tooths. spades and Forstners that cut the entire radius as
they progress into dry end grain would likely overstress the bit and its
shaft, the chuck and its Jarno & Morse tapers and generate excessive
heat. I may be wrong, but I wonder if anyone here drills out deep 5+"
holes in hard dry end grain without the tedium of going thru the sizes.

I think the size of the vase's orifice would limit the useful size of a
drill bit, while a boring bar bit could be extended or swivelled to make
the blank's internal diameter greater than the entry.

Eh Leo, does my 9" Sheldon qualify?


Turn to Safety, Arch
Fortiter


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