Well, I'm finding that any of my bits (stubbies from Ruth, brad-point or "regular") are wandering when the divot for the start isn't centered.
Before you jump on this, please read the rest. Here are the steps I'm going through for these items that need to be chucked and drilled:
- Round a 6" long piece between centers, make a tenon on one end (usually the tailstock end) with a good shoulder and what seems long enough. Example: current piece on lathe is oak that's at least 100 years old, very tight grained and dry. Tenon is .6" long, well-shaped tenon ~.7" diameter.
- Place tenon in Talon chuck with spigot jaws, not tightened yet. Bring up tailstock and insert nose of live center in the existing divot from original turning
- Use tailstock to position stock snuggly against jaws, tighten chuck
- Remove tailstock and get ready to drill
Problem is, the stock moves at Step #4 -- I back off the tailstock, and the end drops. How far? Mmmmm, 1mm or so. I've tried using a skew point to get a better centered divot, but the divot is still off center. If I were simply going to turn the stock without drilling it, it might not matter, but trying to get a good hole drilled when the stock isn't straight is frustrating. Any of the aforementioned bits flex enough to follow that deviation from straight out the Jacob's chuck, I can see them move as they enter the hole. I have had a similar problem on my Jet lathe, so the problem seems to lie either in my chuck, or in some mental lapse on my part.