Step 4: Preparing the blank
Get ready to cut!
Yes, seriously. It's not impossible.
Now, look at your log. Now back at my bowl. Now back at your log.
Now visualize the bowl in the log. You need to cut a chunk of your log that you will be able to turn your bowl from.
One note: it may seem natural to turn a bowl with the endgrain parallel to the axis of rotation. The log is circular, so you just crosscut a piece that is tall enough or the bowl, right? wrong. The grain is not oriented the same way as with spindle turning. You can, but it's much harder to make an endgrain bowl.
Instead, we are going to rip cut down the middle of the log to make a...semicircular prism. The flat face is what you put on the faceplate.
When the bowl is done, the grain will be running through it sideways.
You want to end up with a bowl blank that can fit on your lathe and can fit the size of the bowl you want. Cutting a perfect square will waste the smallest amount of wood. You want to cut down along the grain of the wood a length that's about the same as the diameter of your log.
Once you've cut down far enough, crosscut to release the piece.
I like to use a bright red sharpie to mark the line to cut, and i actually put my log on the lathe and use the tailstock to hold it on place while I'm cutting. Make sure you tie the log to the bed in case it slips.
Use your entire body while cutting, (like hand planing) not just your arm. You'll cut faster and you'll be less sore. If you feel like you need to push too hard to get a decent cut, sharpen the saw. I use an abrasive dremel wheel and lightly touch each tooth.
Once I'm finally done cutting the rough blank, I lay out the biggest circle that will fit on the face. Draw lines corner to corner to find the approximate center, then use a compass and move the center around to find the center of the largest circle.
Now temporarily mount the log on the lathe. Just use a spur center to hold the log on its centerpoint. Spin the log and see if the corners hit the bed of the lathe. If any of them do, mark the corner and cut it off. Once you're done, screw on the faceplate in the center. Make sure you use wood screws and not drywall screws. Drywall screws are brittle and can easily shear off. Also, it might be a good idea to drill pilot holes because the screws can get suck if the wood moves too much. This happened to me once and i had to drill out the screw. It's a good way to ruin a good day.
Now you get to start turning!