So what's the secret to getting a bowl blank properly centered?

"Mike Rinken" wrote: (clip) this new blank wobbles so much and I'm trying to find the best way to center it between the centers. (clip) I am rounding out the blank initially on the bandsaw, but man does this thing make the lathe wobble. I'm using a Jet mini lathe. (clip) ^^^^^^^^^^^^^^ The Jet mini is not a heavyweight, so you have to run slow, and try to get the blank in pretty good balance from the start. Assuming you are mainly trying to find a centerline that minimizes vibration, here is something to try: slip the drive belt off, so the spindle is free to rotate. The heavy side will go to the bottom. Shift the spur drive and/or live center until the blank does not have a heavy side. Then put the belt back on and proceed.

First off, I usually use a faceplate and live center for that operation, not two centers. It's easier to get the blank positioned properly, but takes a little more time. Build yourself a giganto-spur by sharpening three or four machine bolts to a point, and bolting them to your faceplate to form a three- or four-prong spur. As they'd be further apart, they'd just naturally force the flat parallel to the faceplate.

Second, I think it's expected that you'd turn the blank by hand and see if it's doing what you want before turning on the lathe. Some adjustment might be needed. As you turn it, see where the edge of the flat part (drive center side) pass by the toolrest; if they all pass at the same spot it will be close to parallel.

Third, I often use a Dewalt powered plane to carve the blank a bit after it's mounted, to get it more balanced. This is after the rough carving-to-shape with a chainsaw. FYI: for reeves drive, it's easier to hand-balance the blank if you set the lathe to the FASTEST speed. That gives the spur a mechanical advantage over the motor, and thus reduces "friction". Remember to slow it down again before spinning up the blank for real. If you have step pulleys, just take the belt off or de-tension it.

=========================== Mike, If you're using pre-cut square blanks, draw a diagnonal line line from corner to corner on both sides. Where the lines intersect will be the center for each side. Place your drive spur on one center and the live center on the other side. You can draw a circle using the center point to use for a guide for cutting with the band saw.

If the pieces aren't square, cut some circles out of plastic, cardboard, or hardboard (Masonite or equavilant). Make these with increasing diameters in the range you expect to be turning (i.e., 3-10 inches, 1/2 in. increments are good). Use these as templates for your bandsaw cuts. These blanks should be close enough in balance to start at the slowest speed on your lathe for rounding into better balance.

If you have varying densities inside the wood, or voids, you may have to manually balance before your 1st cut. Suspend the piece loosely between centers; allow it to rotate to its natural balance, the low side will be heaviest. Raise slightly and repeat until you no longer have a "low" side. That should be near you balance point for turning.

Ken Moon Webberville, TX.

Thanks for all the great advice. I've gotten better at finding the "center" on both sides and improved my method this weekend. The blanks I got we're from Rockler and all 6 turned out well once I started getting them in shape on the lathe. I actually clamped the lathe to my workbench and that took a lot of the vibration out. I also cut the tenon on the bottom for the chuck and then decided to cut a tenon on the top to flatten it out now that I had turned a center and that obviously dampened it down.

Now I just gotta get a chuck!