Messages

The "acid" test of a drill bit is in the chips (actually shavings) that come out while drilling.
1. Are there 2 of them (1 from each cutting edge)?
2. Are they equal (the same size ie thickness, width, not length)
If there are not 2 or are of different sizes, you do NOT have an ideal symmetrical drill bit. However, you can purposefully offset the center to increase the size of the hole. The above videos that I listed, cover this well.
This assumes all the other factors (angles, clearances, etc.) are correct which with the DBS they should be.
If one chip is smaller or not there, then that tells you that cutting edge has been ground off a little bit more than the other.

Elden

Ken in regard to your question, I believe your assumption of a pilot hole is correct as long as it of sufficient size to contain the chisel point or chisel edge. Of course, the said bit needs to be properly sharpened.
Some excellent reference material about drill bits are found at:

http://www.youtube.com/watch?v=rUMTJ9GZIC8&feature=endscreen
http://www.youtube.com/watch?v=hJItj_ISurY
http://www.youtube.com/watch?v=cqn2VPGYA9c
All 3 are by tubalcain

and:

http://www.youtube.com/watch?v=5n0PgLuSISE
by machiningmoments.

Elden

Anyone have experience sharpening knives while being seated? I have been making some progress on the learning curve, but would appreciate any advice. I am positioned on the opposite side of the Tormek than the operators in the  pictures that I see sharpening knives.
Thanks,
Elden