Originally posted by Petricore
<br />Chris, what do you use to hold the blank when you drill it ? I have a nova chuck I was going to use. Do you get it pretty darn straight with a chuck, or what is your method ?
I have a Nova midi chuck (the adjustment uses two rods). I put the blank in the chuck and tighten it most of the way. Next I pull the tailstock up so the drill bit in the Jacob's chuck is within about 1/4 of an inch from the blank, then lock down the tailstock. I rotate the headstock by hand while looking at the very bottom of the bit and blank and adjust the blank (tapping on it with an adjustment rod) until it looks like the blank is centered. I turn on the lathe, set at 500 rpm, and sight down the drill bit, the blank should spin in place without looking lopsided. If the blank looks out of balance, just try to readjust and retest. The first few times it takes some tinkering to get the blank centered, but after a few dozen it gets to be much quicker and easier. Once the blank is centered, tighten the chuck all the way.
Drilling on the lathe will give you great accuracy, though it looks funny watching the spinning wood and the stationary drill bit. I usually advance the bit in for the first couple of inches, until the shavings stop flowing easily. I pull the tailstock away and crank the bit back in (leave the lathe on) then run the tailstock up until the bit is touching the bottom of the hole, lock in place and advance the bit. After that the shavings don't flow as easily and I pull the tailstock out after about 1/4 to 1/2 inch increments, cranking the bit back in and then moving the tailstock up to the bottom of the hole again. Be sure to clear the flutes of shavings before reinserting the drill bit.
A couple of times I have pulled the blank out of the chuck when removing the tailstock. I stop the lathe and leave the blank on the bit and advance the tailstock until the blank fits back into the chuck, that way your hole and bit are still lined up. Tighten the chuck again.
Sorry to be so wordy - it would take just a couple of minutes to show you, but <s>15</s> 30 minutes of typing and thinking to tell you. Let me know if I left something out.
Others may use a different method, I just learned by trying things out. Practice on some junky blanks.
I turn the crank about the speed it feels I can go. Some materials are easy to drill and some are more difficult - just don't try to rush. When you get close to the end, go slowly and withdraw the bit more often. With some materials, antler and some acrylics, I wrap electrical tape around the bottom 1/2 inch of the blank, before placing it in the chuck, to give it added stability. Blowouts are not common, but are very irritating.
Chris